arch/mips/kvm/emulate.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * KVM/MIPS: Instruction/Exception emulation
   7  *
   8  * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
   9  * Authors: Sanjay Lal <sanjayl@kymasys.com>
  10  */
  11
  12 #include <linux/errno.h>
  13 #include <linux/err.h>
  14 #include <linux/ktime.h>
  15 #include <linux/kvm_host.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/fs.h>
  18 #include <linux/memblock.h>
  19 #include <linux/random.h>
  20 #include <asm/page.h>
  21 #include <asm/cacheflush.h>
  22 #include <asm/cacheops.h>
  23 #include <asm/cpu-info.h>
  24 #include <asm/mmu_context.h>
  25 #include <asm/tlbflush.h>
  26 #include <asm/inst.h>
  27
  28 #undef CONFIG_MIPS_MT
  29 #include <asm/r4kcache.h>
  30 #define CONFIG_MIPS_MT
  31
  32 #include "interrupt.h"
  33 #include "commpage.h"
  34
  35 #include "trace.h"
  36
  37 /*
  38  * Compute the return address and do emulate branch simulation, if required.
  39  * This function should be called only in branch delay slot active.
  40  */
  41 static int kvm_compute_return_epc(struct kvm_vcpu *vcpu, unsigned long instpc,
  42                                   unsigned long *out)
  43 {
  44         unsigned int dspcontrol;
  45         union mips_instruction insn;
  46         struct kvm_vcpu_arch *arch = &vcpu->arch;
  47         long epc = instpc;
  48         long nextpc;
  49         int err;
  50
  51         if (epc & 3) {
  52                 kvm_err("%s: unaligned epc\n", __func__);
  53                 return -EINVAL;
  54         }
  55
  56         /* Read the instruction */
  57         err = kvm_get_badinstrp((u32 *)epc, vcpu, &insn.word);
  58         if (err)
  59                 return err;
  60
  61         switch (insn.i_format.opcode) {
  62                 /* jr and jalr are in r_format format. */
  63         case spec_op:
  64                 switch (insn.r_format.func) {
  65                 case jalr_op:
  66                         arch->gprs[insn.r_format.rd] = epc + 8;
  67                         /* Fall through */
  68                 case jr_op:
  69                         nextpc = arch->gprs[insn.r_format.rs];
  70                         break;
  71                 default:
  72                         return -EINVAL;
  73                 }
  74                 break;
  75
  76                 /*
  77                  * This group contains:
  78                  * bltz_op, bgez_op, bltzl_op, bgezl_op,
  79                  * bltzal_op, bgezal_op, bltzall_op, bgezall_op.
  80                  */
  81         case bcond_op:
  82                 switch (insn.i_format.rt) {
  83                 case bltz_op:
  84                 case bltzl_op:
  85                         if ((long)arch->gprs[insn.i_format.rs] < 0)
  86                                 epc = epc + 4 + (insn.i_format.simmediate << 2);
  87                         else
  88                                 epc += 8;
  89                         nextpc = epc;
  90                         break;
  91
  92                 case bgez_op:
  93                 case bgezl_op:
  94                         if ((long)arch->gprs[insn.i_format.rs] >= 0)
  95                                 epc = epc + 4 + (insn.i_format.simmediate << 2);
  96                         else
  97                                 epc += 8;
  98                         nextpc = epc;
  99                         break;
 100
 101                 case bltzal_op:
 102                 case bltzall_op:
 103                         arch->gprs[31] = epc + 8;
 104                         if ((long)arch->gprs[insn.i_format.rs] < 0)
 105                                 epc = epc + 4 + (insn.i_format.simmediate << 2);
 106                         else
 107                                 epc += 8;
 108                         nextpc = epc;
 109                         break;
 110
 111                 case bgezal_op:
 112                 case bgezall_op:
 113                         arch->gprs[31] = epc + 8;
 114                         if ((long)arch->gprs[insn.i_format.rs] >= 0)
 115                                 epc = epc + 4 + (insn.i_format.simmediate << 2);
 116                         else
 117                                 epc += 8;
 118                         nextpc = epc;
 119                         break;
 120                 case bposge32_op:
 121                         if (!cpu_has_dsp) {
 122                                 kvm_err("%s: DSP branch but not DSP ASE\n",
 123                                         __func__);
 124                                 return -EINVAL;
 125                         }
 126
 127                         dspcontrol = rddsp(0x01);
 128
 129                         if (dspcontrol >= 32)
 130                                 epc = epc + 4 + (insn.i_format.simmediate << 2);
 131                         else
 132                                 epc += 8;
 133                         nextpc = epc;
 134                         break;
 135                 default:
 136                         return -EINVAL;
 137                 }
 138                 break;
 139
 140                 /* These are unconditional and in j_format. */
 141         case jal_op:
 142                 arch->gprs[31] = instpc + 8;
 143                 /* fall through */
 144         case j_op:
 145                 epc += 4;
 146                 epc >>= 28;
 147                 epc <<= 28;
 148                 epc |= (insn.j_format.target << 2);
 149                 nextpc = epc;
 150                 break;
 151
 152                 /* These are conditional and in i_format. */
 153         case beq_op:
 154         case beql_op:
 155                 if (arch->gprs[insn.i_format.rs] ==
 156                     arch->gprs[insn.i_format.rt])
 157                         epc = epc + 4 + (insn.i_format.simmediate << 2);
 158                 else
 159                         epc += 8;
 160                 nextpc = epc;
 161                 break;
 162
 163         case bne_op:
 164         case bnel_op:
 165                 if (arch->gprs[insn.i_format.rs] !=
 166                     arch->gprs[insn.i_format.rt])
 167                         epc = epc + 4 + (insn.i_format.simmediate << 2);
 168                 else
 169                         epc += 8;
 170                 nextpc = epc;
 171                 break;
 172
 173         case blez_op:   /* POP06 */
 174 #ifndef CONFIG_CPU_MIPSR6
 175         case blezl_op:  /* removed in R6 */
 176 #endif
 177                 if (insn.i_format.rt != 0)
 178                         goto compact_branch;
 179                 if ((long)arch->gprs[insn.i_format.rs] <= 0)
 180                         epc = epc + 4 + (insn.i_format.simmediate << 2);
 181                 else
 182                         epc += 8;
 183                 nextpc = epc;
 184                 break;
 185
 186         case bgtz_op:   /* POP07 */
 187 #ifndef CONFIG_CPU_MIPSR6
 188         case bgtzl_op:  /* removed in R6 */
 189 #endif
 190                 if (insn.i_format.rt != 0)
 191                         goto compact_branch;
 192                 if ((long)arch->gprs[insn.i_format.rs] > 0)
 193                         epc = epc + 4 + (insn.i_format.simmediate << 2);
 194                 else
 195                         epc += 8;
 196                 nextpc = epc;
 197                 break;
 198
 199                 /* And now the FPA/cp1 branch instructions. */
 200         case cop1_op:
 201                 kvm_err("%s: unsupported cop1_op\n", __func__);
 202                 return -EINVAL;
 203
 204 #ifdef CONFIG_CPU_MIPSR6
 205         /* R6 added the following compact branches with forbidden slots */
 206         case blezl_op:  /* POP26 */
 207         case bgtzl_op:  /* POP27 */
 208                 /* only rt == 0 isn't compact branch */
 209                 if (insn.i_format.rt != 0)
 210                         goto compact_branch;
 211                 return -EINVAL;
 212         case pop10_op:
 213         case pop30_op:
 214                 /* only rs == rt == 0 is reserved, rest are compact branches */
 215                 if (insn.i_format.rs != 0 || insn.i_format.rt != 0)
 216                         goto compact_branch;
 217                 return -EINVAL;
 218         case pop66_op:
 219         case pop76_op:
 220                 /* only rs == 0 isn't compact branch */
 221                 if (insn.i_format.rs != 0)
 222                         goto compact_branch;
 223                 return -EINVAL;
 224 compact_branch:
 225                 /*
 226                  * If we've hit an exception on the forbidden slot, then
 227                  * the branch must not have been taken.
 228                  */
 229                 epc += 8;
 230                 nextpc = epc;
 231                 break;
 232 #else
 233 compact_branch:
 234                 /* Fall through - Compact branches not supported before R6 */
 235 #endif
 236         default:
 237                 return -EINVAL;
 238         }
 239
 240         *out = nextpc;
 241         return 0;
 242 }
 243
 244 enum emulation_result update_pc(struct kvm_vcpu *vcpu, u32 cause)
 245 {
 246         int err;
 247
 248         if (cause & CAUSEF_BD) {
 249                 err = kvm_compute_return_epc(vcpu, vcpu->arch.pc,
 250                                              &vcpu->arch.pc);
 251                 if (err)
 252                         return EMULATE_FAIL;
 253         } else {
 254                 vcpu->arch.pc += 4;
 255         }
 256
 257         kvm_debug("update_pc(): New PC: %#lx\n", vcpu->arch.pc);
 258
 259         return EMULATE_DONE;
 260 }
 261
 262 /**
 263  * kvm_get_badinstr() - Get bad instruction encoding.
 264  * @opc:        Guest pointer to faulting instruction.
 265  * @vcpu:       KVM VCPU information.
 266  *
 267  * Gets the instruction encoding of the faulting instruction, using the saved
 268  * BadInstr register value if it exists, otherwise falling back to reading guest
 269  * memory at @opc.
 270  *
 271  * Returns:     The instruction encoding of the faulting instruction.
 272  */
 273 int kvm_get_badinstr(u32 *opc, struct kvm_vcpu *vcpu, u32 *out)
 274 {
 275         if (cpu_has_badinstr) {
 276                 *out = vcpu->arch.host_cp0_badinstr;
 277                 return 0;
 278         } else {
 279                 return kvm_get_inst(opc, vcpu, out);
 280         }
 281 }
 282
 283 /**
 284  * kvm_get_badinstrp() - Get bad prior instruction encoding.
 285  * @opc:        Guest pointer to prior faulting instruction.
 286  * @vcpu:       KVM VCPU information.
 287  *
 288  * Gets the instruction encoding of the prior faulting instruction (the branch
 289  * containing the delay slot which faulted), using the saved BadInstrP register
 290  * value if it exists, otherwise falling back to reading guest memory at @opc.
 291  *
 292  * Returns:     The instruction encoding of the prior faulting instruction.
 293  */
 294 int kvm_get_badinstrp(u32 *opc, struct kvm_vcpu *vcpu, u32 *out)
 295 {
 296         if (cpu_has_badinstrp) {
 297                 *out = vcpu->arch.host_cp0_badinstrp;
 298                 return 0;
 299         } else {
 300                 return kvm_get_inst(opc, vcpu, out);
 301         }
 302 }
 303
 304 /**
 305  * kvm_mips_count_disabled() - Find whether the CP0_Count timer is disabled.
 306  * @vcpu:       Virtual CPU.
 307  *
 308  * Returns:     1 if the CP0_Count timer is disabled by either the guest
 309  *              CP0_Cause.DC bit or the count_ctl.DC bit.
 310  *              0 otherwise (in which case CP0_Count timer is running).
 311  */
 312 int kvm_mips_count_disabled(struct kvm_vcpu *vcpu)
 313 {
 314         struct mips_coproc *cop0 = vcpu->arch.cop0;
 315
 316         return  (vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC) ||
 317                 (kvm_read_c0_guest_cause(cop0) & CAUSEF_DC);
 318 }
 319
 320 /**
 321  * kvm_mips_ktime_to_count() - Scale ktime_t to a 32-bit count.
 322  *
 323  * Caches the dynamic nanosecond bias in vcpu->arch.count_dyn_bias.
 324  *
 325  * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
 326  */
 327 static u32 kvm_mips_ktime_to_count(struct kvm_vcpu *vcpu, ktime_t now)
 328 {
 329         s64 now_ns, periods;
 330         u64 delta;
 331
 332         now_ns = ktime_to_ns(now);
 333         delta = now_ns + vcpu->arch.count_dyn_bias;
 334
 335         if (delta >= vcpu->arch.count_period) {
 336                 /* If delta is out of safe range the bias needs adjusting */
 337                 periods = div64_s64(now_ns, vcpu->arch.count_period);
 338                 vcpu->arch.count_dyn_bias = -periods * vcpu->arch.count_period;
 339                 /* Recalculate delta with new bias */
 340                 delta = now_ns + vcpu->arch.count_dyn_bias;
 341         }
 342
 343         /*
 344          * We've ensured that:
 345          *   delta < count_period
 346          *
 347          * Therefore the intermediate delta*count_hz will never overflow since
 348          * at the boundary condition:
 349          *   delta = count_period
 350          *   delta = NSEC_PER_SEC * 2^32 / count_hz
 351          *   delta * count_hz = NSEC_PER_SEC * 2^32
 352          */
 353         return div_u64(delta * vcpu->arch.count_hz, NSEC_PER_SEC);
 354 }
 355
 356 /**
 357  * kvm_mips_count_time() - Get effective current time.
 358  * @vcpu:       Virtual CPU.
 359  *
 360  * Get effective monotonic ktime. This is usually a straightforward ktime_get(),
 361  * except when the master disable bit is set in count_ctl, in which case it is
 362  * count_resume, i.e. the time that the count was disabled.
 363  *
 364  * Returns:     Effective monotonic ktime for CP0_Count.
 365  */
 366 static inline ktime_t kvm_mips_count_time(struct kvm_vcpu *vcpu)
 367 {
 368         if (unlikely(vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC))
 369                 return vcpu->arch.count_resume;
 370
 371         return ktime_get();
 372 }
 373
 374 /**
 375  * kvm_mips_read_count_running() - Read the current count value as if running.
 376  * @vcpu:       Virtual CPU.
 377  * @now:        Kernel time to read CP0_Count at.
 378  *
 379  * Returns the current guest CP0_Count register at time @now and handles if the
 380  * timer interrupt is pending and hasn't been handled yet.
 381  *
 382  * Returns:     The current value of the guest CP0_Count register.
 383  */
 384 static u32 kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now)
 385 {
 386         struct mips_coproc *cop0 = vcpu->arch.cop0;
 387         ktime_t expires, threshold;
 388         u32 count, compare;
 389         int running;
 390
 391         /* Calculate the biased and scaled guest CP0_Count */
 392         count = vcpu->arch.count_bias + kvm_mips_ktime_to_count(vcpu, now);
 393         compare = kvm_read_c0_guest_compare(cop0);
 394
 395         /*
 396          * Find whether CP0_Count has reached the closest timer interrupt. If
 397          * not, we shouldn't inject it.
 398          */
 399         if ((s32)(count - compare) < 0)
 400                 return count;
 401
 402         /*
 403          * The CP0_Count we're going to return has already reached the closest
 404          * timer interrupt. Quickly check if it really is a new interrupt by
 405          * looking at whether the interval until the hrtimer expiry time is
 406          * less than 1/4 of the timer period.
 407          */
 408         expires = hrtimer_get_expires(&vcpu->arch.comparecount_timer);
 409         threshold = ktime_add_ns(now, vcpu->arch.count_period / 4);
 410         if (ktime_before(expires, threshold)) {
 411                 /*
 412                  * Cancel it while we handle it so there's no chance of
 413                  * interference with the timeout handler.
 414                  */
 415                 running = hrtimer_cancel(&vcpu->arch.comparecount_timer);
 416
 417                 /* Nothing should be waiting on the timeout */
 418                 kvm_mips_callbacks->queue_timer_int(vcpu);
 419
 420                 /*
 421                  * Restart the timer if it was running based on the expiry time
 422                  * we read, so that we don't push it back 2 periods.
 423                  */
 424                 if (running) {
 425                         expires = ktime_add_ns(expires,
 426                                                vcpu->arch.count_period);
 427                         hrtimer_start(&vcpu->arch.comparecount_timer, expires,
 428                                       HRTIMER_MODE_ABS);
 429                 }
 430         }
 431
 432         return count;
 433 }
 434
 435 /**
 436  * kvm_mips_read_count() - Read the current count value.
 437  * @vcpu:       Virtual CPU.
 438  *
 439  * Read the current guest CP0_Count value, taking into account whether the timer
 440  * is stopped.
 441  *
 442  * Returns:     The current guest CP0_Count value.
 443  */
 444 u32 kvm_mips_read_count(struct kvm_vcpu *vcpu)
 445 {
 446         struct mips_coproc *cop0 = vcpu->arch.cop0;
 447
 448         /* If count disabled just read static copy of count */
 449         if (kvm_mips_count_disabled(vcpu))
 450                 return kvm_read_c0_guest_count(cop0);
 451
 452         return kvm_mips_read_count_running(vcpu, ktime_get());
 453 }
 454
 455 /**
 456  * kvm_mips_freeze_hrtimer() - Safely stop the hrtimer.
 457  * @vcpu:       Virtual CPU.
 458  * @count:      Output pointer for CP0_Count value at point of freeze.
 459  *
 460  * Freeze the hrtimer safely and return both the ktime and the CP0_Count value
 461  * at the point it was frozen. It is guaranteed that any pending interrupts at
 462  * the point it was frozen are handled, and none after that point.
 463  *
 464  * This is useful where the time/CP0_Count is needed in the calculation of the
 465  * new parameters.
 466  *
 467  * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
 468  *
 469  * Returns:     The ktime at the point of freeze.
 470  */
 471 ktime_t kvm_mips_freeze_hrtimer(struct kvm_vcpu *vcpu, u32 *count)
 472 {
 473         ktime_t now;
 474
 475         /* stop hrtimer before finding time */
 476         hrtimer_cancel(&vcpu->arch.comparecount_timer);
 477         now = ktime_get();
 478
 479         /* find count at this point and handle pending hrtimer */
 480         *count = kvm_mips_read_count_running(vcpu, now);
 481
 482         return now;
 483 }
 484
 485 /**
 486  * kvm_mips_resume_hrtimer() - Resume hrtimer, updating expiry.
 487  * @vcpu:       Virtual CPU.
 488  * @now:        ktime at point of resume.
 489  * @count:      CP0_Count at point of resume.
 490  *
 491  * Resumes the timer and updates the timer expiry based on @now and @count.
 492  * This can be used in conjunction with kvm_mips_freeze_timer() when timer
 493  * parameters need to be changed.
 494  *
 495  * It is guaranteed that a timer interrupt immediately after resume will be
 496  * handled, but not if CP_Compare is exactly at @count. That case is already
 497  * handled by kvm_mips_freeze_timer().
 498  *
 499  * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
 500  */
 501 static void kvm_mips_resume_hrtimer(struct kvm_vcpu *vcpu,
 502                                     ktime_t now, u32 count)
 503 {
 504         struct mips_coproc *cop0 = vcpu->arch.cop0;
 505         u32 compare;
 506         u64 delta;
 507         ktime_t expire;
 508
 509         /* Calculate timeout (wrap 0 to 2^32) */
 510         compare = kvm_read_c0_guest_compare(cop0);
 511         delta = (u64)(u32)(compare - count - 1) + 1;
 512         delta = div_u64(delta * NSEC_PER_SEC, vcpu->arch.count_hz);
 513         expire = ktime_add_ns(now, delta);
 514
 515         /* Update hrtimer to use new timeout */
 516         hrtimer_cancel(&vcpu->arch.comparecount_timer);
 517         hrtimer_start(&vcpu->arch.comparecount_timer, expire, HRTIMER_MODE_ABS);
 518 }
 519
 520 /**
 521  * kvm_mips_restore_hrtimer() - Restore hrtimer after a gap, updating expiry.
 522  * @vcpu:       Virtual CPU.
 523  * @before:     Time before Count was saved, lower bound of drift calculation.
 524  * @count:      CP0_Count at point of restore.
 525  * @min_drift:  Minimum amount of drift permitted before correction.
 526  *              Must be <= 0.
 527  *
 528  * Restores the timer from a particular @count, accounting for drift. This can
 529  * be used in conjunction with kvm_mips_freeze_timer() when a hardware timer is
 530  * to be used for a period of time, but the exact ktime corresponding to the
 531  * final Count that must be restored is not known.
 532  *
 533  * It is gauranteed that a timer interrupt immediately after restore will be
 534  * handled, but not if CP0_Compare is exactly at @count. That case should
 535  * already be handled when the hardware timer state is saved.
 536  *
 537  * Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is not
 538  * stopped).
 539  *
 540  * Returns:     Amount of correction to count_bias due to drift.
 541  */
 542 int kvm_mips_restore_hrtimer(struct kvm_vcpu *vcpu, ktime_t before,
 543                              u32 count, int min_drift)
 544 {
 545         ktime_t now, count_time;
 546         u32 now_count, before_count;
 547         u64 delta;
 548         int drift, ret = 0;
 549
 550         /* Calculate expected count at before */
 551         before_count = vcpu->arch.count_bias +
 552                         kvm_mips_ktime_to_count(vcpu, before);
 553
 554         /*
 555          * Detect significantly negative drift, where count is lower than
 556          * expected. Some negative drift is expected when hardware counter is
 557          * set after kvm_mips_freeze_timer(), and it is harmless to allow the
 558          * time to jump forwards a little, within reason. If the drift is too
 559          * significant, adjust the bias to avoid a big Guest.CP0_Count jump.
 560          */
 561         drift = count - before_count;
 562         if (drift < min_drift) {
 563                 count_time = before;
 564                 vcpu->arch.count_bias += drift;
 565                 ret = drift;
 566                 goto resume;
 567         }
 568
 569         /* Calculate expected count right now */
 570         now = ktime_get();
 571         now_count = vcpu->arch.count_bias + kvm_mips_ktime_to_count(vcpu, now);
 572
 573         /*
 574          * Detect positive drift, where count is higher than expected, and
 575          * adjust the bias to avoid guest time going backwards.
 576          */
 577         drift = count - now_count;
 578         if (drift > 0) {
 579                 count_time = now;
 580                 vcpu->arch.count_bias += drift;
 581                 ret = drift;
 582                 goto resume;
 583         }
 584
 585         /* Subtract nanosecond delta to find ktime when count was read */
 586         delta = (u64)(u32)(now_count - count);
 587         delta = div_u64(delta * NSEC_PER_SEC, vcpu->arch.count_hz);
 588         count_time = ktime_sub_ns(now, delta);
 589
 590 resume:
 591         /* Resume using the calculated ktime */
 592         kvm_mips_resume_hrtimer(vcpu, count_time, count);
 593         return ret;
 594 }
 595
 596 /**
 597  * kvm_mips_write_count() - Modify the count and update timer.
 598  * @vcpu:       Virtual CPU.
 599  * @count:      Guest CP0_Count value to set.
 600  *
 601  * Sets the CP0_Count value and updates the timer accordingly.
 602  */
 603 void kvm_mips_write_count(struct kvm_vcpu *vcpu, u32 count)
 604 {
 605         struct mips_coproc *cop0 = vcpu->arch.cop0;
 606         ktime_t now;
 607
 608         /* Calculate bias */
 609         now = kvm_mips_count_time(vcpu);
 610         vcpu->arch.count_bias = count - kvm_mips_ktime_to_count(vcpu, now);
 611
 612         if (kvm_mips_count_disabled(vcpu))
 613                 /* The timer's disabled, adjust the static count */
 614                 kvm_write_c0_guest_count(cop0, count);
 615         else
 616                 /* Update timeout */
 617                 kvm_mips_resume_hrtimer(vcpu, now, count);
 618 }
 619
 620 /**
 621  * kvm_mips_init_count() - Initialise timer.
 622  * @vcpu:       Virtual CPU.
 623  * @count_hz:   Frequency of timer.
 624  *
 625  * Initialise the timer to the specified frequency, zero it, and set it going if
 626  * it's enabled.
 627  */
 628 void kvm_mips_init_count(struct kvm_vcpu *vcpu, unsigned long count_hz)
 629 {
 630         vcpu->arch.count_hz = count_hz;
 631         vcpu->arch.count_period = div_u64((u64)NSEC_PER_SEC << 32, count_hz);
 632         vcpu->arch.count_dyn_bias = 0;
 633
 634         /* Starting at 0 */
 635         kvm_mips_write_count(vcpu, 0);
 636 }
 637
 638 /**
 639  * kvm_mips_set_count_hz() - Update the frequency of the timer.
 640  * @vcpu:       Virtual CPU.
 641  * @count_hz:   Frequency of CP0_Count timer in Hz.
 642  *
 643  * Change the frequency of the CP0_Count timer. This is done atomically so that
 644  * CP0_Count is continuous and no timer interrupt is lost.
 645  *
 646  * Returns:     -EINVAL if @count_hz is out of range.
 647  *              0 on success.
 648  */
 649 int kvm_mips_set_count_hz(struct kvm_vcpu *vcpu, s64 count_hz)
 650 {
 651         struct mips_coproc *cop0 = vcpu->arch.cop0;
 652         int dc;
 653         ktime_t now;
 654         u32 count;
 655
 656         /* ensure the frequency is in a sensible range... */
 657         if (count_hz <= 0 || count_hz > NSEC_PER_SEC)
 658                 return -EINVAL;
 659         /* ... and has actually changed */
 660         if (vcpu->arch.count_hz == count_hz)
 661                 return 0;
 662
 663         /* Safely freeze timer so we can keep it continuous */
 664         dc = kvm_mips_count_disabled(vcpu);
 665         if (dc) {
 666                 now = kvm_mips_count_time(vcpu);
 667                 count = kvm_read_c0_guest_count(cop0);
 668         } else {
 669                 now = kvm_mips_freeze_hrtimer(vcpu, &count);
 670         }
 671
 672         /* Update the frequency */
 673         vcpu->arch.count_hz = count_hz;
 674         vcpu->arch.count_period = div_u64((u64)NSEC_PER_SEC << 32, count_hz);
 675         vcpu->arch.count_dyn_bias = 0;
 676
 677         /* Calculate adjusted bias so dynamic count is unchanged */
 678         vcpu->arch.count_bias = count - kvm_mips_ktime_to_count(vcpu, now);
 679
 680         /* Update and resume hrtimer */
 681         if (!dc)
 682                 kvm_mips_resume_hrtimer(vcpu, now, count);
 683         return 0;
 684 }
 685
 686 /**
 687  * kvm_mips_write_compare() - Modify compare and update timer.
 688  * @vcpu:       Virtual CPU.
 689  * @compare:    New CP0_Compare value.
 690  * @ack:        Whether to acknowledge timer interrupt.
 691  *
 692  * Update CP0_Compare to a new value and update the timeout.
 693  * If @ack, atomically acknowledge any pending timer interrupt, otherwise ensure
 694  * any pending timer interrupt is preserved.
 695  */
 696 void kvm_mips_write_compare(struct kvm_vcpu *vcpu, u32 compare, bool ack)
 697 {
 698         struct mips_coproc *cop0 = vcpu->arch.cop0;
 699         int dc;
 700         u32 old_compare = kvm_read_c0_guest_compare(cop0);
 701         s32 delta = compare - old_compare;
 702         u32 cause;
 703         ktime_t now = ktime_set(0, 0); /* silence bogus GCC warning */
 704         u32 count;
 705
 706         /* if unchanged, must just be an ack */
 707         if (old_compare == compare) {
 708                 if (!ack)
 709                         return;
 710                 kvm_mips_callbacks->dequeue_timer_int(vcpu);
 711                 kvm_write_c0_guest_compare(cop0, compare);
 712                 return;
 713         }
 714
 715         /*
 716          * If guest CP0_Compare moves forward, CP0_GTOffset should be adjusted
 717          * too to prevent guest CP0_Count hitting guest CP0_Compare.
 718          *
 719          * The new GTOffset corresponds to the new value of CP0_Compare, and is
 720          * set prior to it being written into the guest context. We disable
 721          * preemption until the new value is written to prevent restore of a
 722          * GTOffset corresponding to the old CP0_Compare value.
 723          */
 724         if (IS_ENABLED(CONFIG_KVM_MIPS_VZ) && delta > 0) {
 725                 preempt_disable();
 726                 write_c0_gtoffset(compare - read_c0_count());
 727                 back_to_back_c0_hazard();
 728         }
 729
 730         /* freeze_hrtimer() takes care of timer interrupts <= count */
 731         dc = kvm_mips_count_disabled(vcpu);
 732         if (!dc)
 733                 now = kvm_mips_freeze_hrtimer(vcpu, &count);
 734
 735         if (ack)
 736                 kvm_mips_callbacks->dequeue_timer_int(vcpu);
 737         else if (IS_ENABLED(CONFIG_KVM_MIPS_VZ))
 738                 /*
 739                  * With VZ, writing CP0_Compare acks (clears) CP0_Cause.TI, so
 740                  * preserve guest CP0_Cause.TI if we don't want to ack it.
 741                  */
 742                 cause = kvm_read_c0_guest_cause(cop0);
 743
 744         kvm_write_c0_guest_compare(cop0, compare);
 745
 746         if (IS_ENABLED(CONFIG_KVM_MIPS_VZ)) {
 747                 if (delta > 0)
 748                         preempt_enable();
 749
 750                 back_to_back_c0_hazard();
 751
 752                 if (!ack && cause & CAUSEF_TI)
 753                         kvm_write_c0_guest_cause(cop0, cause);
 754         }
 755
 756         /* resume_hrtimer() takes care of timer interrupts > count */
 757         if (!dc)
 758                 kvm_mips_resume_hrtimer(vcpu, now, count);
 759
 760         /*
 761          * If guest CP0_Compare is moving backward, we delay CP0_GTOffset change
 762          * until after the new CP0_Compare is written, otherwise new guest
 763          * CP0_Count could hit new guest CP0_Compare.
 764          */
 765         if (IS_ENABLED(CONFIG_KVM_MIPS_VZ) && delta <= 0)
 766                 write_c0_gtoffset(compare - read_c0_count());
 767 }
 768
 769 /**
 770  * kvm_mips_count_disable() - Disable count.
 771  * @vcpu:       Virtual CPU.
 772  *
 773  * Disable the CP0_Count timer. A timer interrupt on or before the final stop
 774  * time will be handled but not after.
 775  *
 776  * Assumes CP0_Count was previously enabled but now Guest.CP0_Cause.DC or
 777  * count_ctl.DC has been set (count disabled).
 778  *
 779  * Returns:     The time that the timer was stopped.
 780  */
 781 static ktime_t kvm_mips_count_disable(struct kvm_vcpu *vcpu)
 782 {
 783         struct mips_coproc *cop0 = vcpu->arch.cop0;
 784         u32 count;
 785         ktime_t now;
 786
 787         /* Stop hrtimer */
 788         hrtimer_cancel(&vcpu->arch.comparecount_timer);
 789
 790         /* Set the static count from the dynamic count, handling pending TI */
 791         now = ktime_get();
 792         count = kvm_mips_read_count_running(vcpu, now);
 793         kvm_write_c0_guest_count(cop0, count);
 794
 795         return now;
 796 }
 797
 798 /**
 799  * kvm_mips_count_disable_cause() - Disable count using CP0_Cause.DC.
 800  * @vcpu:       Virtual CPU.
 801  *
 802  * Disable the CP0_Count timer and set CP0_Cause.DC. A timer interrupt on or
 803  * before the final stop time will be handled if the timer isn't disabled by
 804  * count_ctl.DC, but not after.
 805  *
 806  * Assumes CP0_Cause.DC is clear (count enabled).
 807  */
 808 void kvm_mips_count_disable_cause(struct kvm_vcpu *vcpu)
 809 {
 810         struct mips_coproc *cop0 = vcpu->arch.cop0;
 811
 812         kvm_set_c0_guest_cause(cop0, CAUSEF_DC);
 813         if (!(vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC))
 814                 kvm_mips_count_disable(vcpu);
 815 }
 816
 817 /**
 818  * kvm_mips_count_enable_cause() - Enable count using CP0_Cause.DC.
 819  * @vcpu:       Virtual CPU.
 820  *
 821  * Enable the CP0_Count timer and clear CP0_Cause.DC. A timer interrupt after
 822  * the start time will be handled if the timer isn't disabled by count_ctl.DC,
 823  * potentially before even returning, so the caller should be careful with
 824  * ordering of CP0_Cause modifications so as not to lose it.
 825  *
 826  * Assumes CP0_Cause.DC is set (count disabled).
 827  */
 828 void kvm_mips_count_enable_cause(struct kvm_vcpu *vcpu)
 829 {
 830         struct mips_coproc *cop0 = vcpu->arch.cop0;
 831         u32 count;
 832
 833         kvm_clear_c0_guest_cause(cop0, CAUSEF_DC);
 834
 835         /*
 836          * Set the dynamic count to match the static count.
 837          * This starts the hrtimer if count_ctl.DC allows it.
 838          * Otherwise it conveniently updates the biases.
 839          */
 840         count = kvm_read_c0_guest_count(cop0);
 841         kvm_mips_write_count(vcpu, count);
 842 }
 843
 844 /**
 845  * kvm_mips_set_count_ctl() - Update the count control KVM register.
 846  * @vcpu:       Virtual CPU.
 847  * @count_ctl:  Count control register new value.
 848  *
 849  * Set the count control KVM register. The timer is updated accordingly.
 850  *
 851  * Returns:     -EINVAL if reserved bits are set.
 852  *              0 on success.
 853  */
 854 int kvm_mips_set_count_ctl(struct kvm_vcpu *vcpu, s64 count_ctl)
 855 {
 856         struct mips_coproc *cop0 = vcpu->arch.cop0;
 857         s64 changed = count_ctl ^ vcpu->arch.count_ctl;
 858         s64 delta;
 859         ktime_t expire, now;
 860         u32 count, compare;
 861
 862         /* Only allow defined bits to be changed */
 863         if (changed & ~(s64)(KVM_REG_MIPS_COUNT_CTL_DC))
 864                 return -EINVAL;
 865
 866         /* Apply new value */
 867         vcpu->arch.count_ctl = count_ctl;
 868
 869         /* Master CP0_Count disable */
 870         if (changed & KVM_REG_MIPS_COUNT_CTL_DC) {
 871                 /* Is CP0_Cause.DC already disabling CP0_Count? */
 872                 if (kvm_read_c0_guest_cause(cop0) & CAUSEF_DC) {
 873                         if (count_ctl & KVM_REG_MIPS_COUNT_CTL_DC)
 874                                 /* Just record the current time */
 875                                 vcpu->arch.count_resume = ktime_get();
 876                 } else if (count_ctl & KVM_REG_MIPS_COUNT_CTL_DC) {
 877                         /* disable timer and record current time */
 878                         vcpu->arch.count_resume = kvm_mips_count_disable(vcpu);
 879                 } else {
 880                         /*
 881                          * Calculate timeout relative to static count at resume
 882                          * time (wrap 0 to 2^32).
 883                          */
 884                         count = kvm_read_c0_guest_count(cop0);
 885                         compare = kvm_read_c0_guest_compare(cop0);
 886                         delta = (u64)(u32)(compare - count - 1) + 1;
 887                         delta = div_u64(delta * NSEC_PER_SEC,
 888                                         vcpu->arch.count_hz);
 889                         expire = ktime_add_ns(vcpu->arch.count_resume, delta);
 890
 891                         /* Handle pending interrupt */
 892                         now = ktime_get();
 893                         if (ktime_compare(now, expire) >= 0)
 894                                 /* Nothing should be waiting on the timeout */
 895                                 kvm_mips_callbacks->queue_timer_int(vcpu);
 896
 897                         /* Resume hrtimer without changing bias */
 898                         count = kvm_mips_read_count_running(vcpu, now);
 899                         kvm_mips_resume_hrtimer(vcpu, now, count);
 900                 }
 901         }
 902
 903         return 0;
 904 }
 905
 906 /**
 907  * kvm_mips_set_count_resume() - Update the count resume KVM register.
 908  * @vcpu:               Virtual CPU.
 909  * @count_resume:       Count resume register new value.
 910  *
 911  * Set the count resume KVM register.
 912  *
 913  * Returns:     -EINVAL if out of valid range (0..now).
 914  *              0 on success.
 915  */
 916 int kvm_mips_set_count_resume(struct kvm_vcpu *vcpu, s64 count_resume)
 917 {
 918         /*
 919          * It doesn't make sense for the resume time to be in the future, as it
 920          * would be possible for the next interrupt to be more than a full
 921          * period in the future.
 922          */
 923         if (count_resume < 0 || count_resume > ktime_to_ns(ktime_get()))
 924                 return -EINVAL;
 925
 926         vcpu->arch.count_resume = ns_to_ktime(count_resume);
 927         return 0;
 928 }
 929
 930 /**
 931  * kvm_mips_count_timeout() - Push timer forward on timeout.
 932  * @vcpu:       Virtual CPU.
 933  *
 934  * Handle an hrtimer event by push the hrtimer forward a period.
 935  *
 936  * Returns:     The hrtimer_restart value to return to the hrtimer subsystem.
 937  */
 938 enum hrtimer_restart kvm_mips_count_timeout(struct kvm_vcpu *vcpu)
 939 {
 940         /* Add the Count period to the current expiry time */
 941         hrtimer_add_expires_ns(&vcpu->arch.comparecount_timer,
 942                                vcpu->arch.count_period);
 943         return HRTIMER_RESTART;
 944 }
 945
 946 enum emulation_result kvm_mips_emul_eret(struct kvm_vcpu *vcpu)
 947 {
 948         struct mips_coproc *cop0 = vcpu->arch.cop0;
 949         enum emulation_result er = EMULATE_DONE;
 950
 951         if (kvm_read_c0_guest_status(cop0) & ST0_ERL) {
 952                 kvm_clear_c0_guest_status(cop0, ST0_ERL);
 953                 vcpu->arch.pc = kvm_read_c0_guest_errorepc(cop0);
 954         } else if (kvm_read_c0_guest_status(cop0) & ST0_EXL) {
 955                 kvm_debug("[%#lx] ERET to %#lx\n", vcpu->arch.pc,
 956                           kvm_read_c0_guest_epc(cop0));
 957                 kvm_clear_c0_guest_status(cop0, ST0_EXL);
 958                 vcpu->arch.pc = kvm_read_c0_guest_epc(cop0);
 959
 960         } else {
 961                 kvm_err("[%#lx] ERET when MIPS_SR_EXL|MIPS_SR_ERL == 0\n",
 962                         vcpu->arch.pc);
 963                 er = EMULATE_FAIL;
 964         }
 965
 966         return er;
 967 }
 968
 969 enum emulation_result kvm_mips_emul_wait(struct kvm_vcpu *vcpu)
 970 {
 971         kvm_debug("[%#lx] !!!WAIT!!! (%#lx)\n", vcpu->arch.pc,
 972                   vcpu->arch.pending_exceptions);
 973
 974         ++vcpu->stat.wait_exits;
 975         trace_kvm_exit(vcpu, KVM_TRACE_EXIT_WAIT);
 976         if (!vcpu->arch.pending_exceptions) {
 977                 kvm_vz_lose_htimer(vcpu);
 978                 vcpu->arch.wait = 1;
 979                 kvm_vcpu_block(vcpu);
 980
 981                 /*
 982                  * We we are runnable, then definitely go off to user space to
 983                  * check if any I/O interrupts are pending.
 984                  */
 985                 if (kvm_check_request(KVM_REQ_UNHALT, vcpu)) {
 986                         kvm_clear_request(KVM_REQ_UNHALT, vcpu);
 987                         vcpu->run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
 988                 }
 989         }
 990
 991         return EMULATE_DONE;
 992 }
 993
 994 static void kvm_mips_change_entryhi(struct kvm_vcpu *vcpu,
 995                                     unsigned long entryhi)
 996 {
 997         struct mips_coproc *cop0 = vcpu->arch.cop0;
 998         struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
 999         int cpu, i;
1000         u32 nasid = entryhi & KVM_ENTRYHI_ASID;
1001
1002         if (((kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID) != nasid)) {
1003                 trace_kvm_asid_change(vcpu, kvm_read_c0_guest_entryhi(cop0) &
1004                                       KVM_ENTRYHI_ASID, nasid);
1005
1006                 /*
1007                  * Flush entries from the GVA page tables.
1008                  * Guest user page table will get flushed lazily on re-entry to
1009                  * guest user if the guest ASID actually changes.
1010                  */
1011                 kvm_mips_flush_gva_pt(kern_mm->pgd, KMF_KERN);
1012
1013                 /*
1014                  * Regenerate/invalidate kernel MMU context.
1015                  * The user MMU context will be regenerated lazily on re-entry
1016                  * to guest user if the guest ASID actually changes.
1017                  */
1018                 preempt_disable();
1019                 cpu = smp_processor_id();
1020                 get_new_mmu_context(kern_mm);
1021                 for_each_possible_cpu(i)
1022                         if (i != cpu)
1023                                 set_cpu_context(i, kern_mm, 0);
1024                 preempt_enable();
1025         }
1026         kvm_write_c0_guest_entryhi(cop0, entryhi);
1027 }
1028
1029 enum emulation_result kvm_mips_emul_tlbr(struct kvm_vcpu *vcpu)
1030 {
1031         struct mips_coproc *cop0 = vcpu->arch.cop0;
1032         struct kvm_mips_tlb *tlb;
1033         unsigned long pc = vcpu->arch.pc;
1034         int index;
1035
1036         index = kvm_read_c0_guest_index(cop0);
1037         if (index < 0 || index >= KVM_MIPS_GUEST_TLB_SIZE) {
1038                 /* UNDEFINED */
1039                 kvm_debug("[%#lx] TLBR Index %#x out of range\n", pc, index);
1040                 index &= KVM_MIPS_GUEST_TLB_SIZE - 1;
1041         }
1042
1043         tlb = &vcpu->arch.guest_tlb[index];
1044         kvm_write_c0_guest_pagemask(cop0, tlb->tlb_mask);
1045         kvm_write_c0_guest_entrylo0(cop0, tlb->tlb_lo[0]);
1046         kvm_write_c0_guest_entrylo1(cop0, tlb->tlb_lo[1]);
1047         kvm_mips_change_entryhi(vcpu, tlb->tlb_hi);
1048
1049         return EMULATE_DONE;
1050 }
1051
1052 /**
1053  * kvm_mips_invalidate_guest_tlb() - Indicates a change in guest MMU map.
1054  * @vcpu:       VCPU with changed mappings.
1055  * @tlb:        TLB entry being removed.
1056  *
1057  * This is called to indicate a single change in guest MMU mappings, so that we
1058  * can arrange TLB flushes on this and other CPUs.
1059  */
1060 static void kvm_mips_invalidate_guest_tlb(struct kvm_vcpu *vcpu,
1061                                           struct kvm_mips_tlb *tlb)
1062 {
1063         struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
1064         struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;
1065         int cpu, i;
1066         bool user;
1067
1068         /* No need to flush for entries which are already invalid */
1069         if (!((tlb->tlb_lo[0] | tlb->tlb_lo[1]) & ENTRYLO_V))
1070                 return;
1071         /* Don't touch host kernel page tables or TLB mappings */
1072         if ((unsigned long)tlb->tlb_hi > 0x7fffffff)
1073                 return;
1074         /* User address space doesn't need flushing for KSeg2/3 changes */
1075         user = tlb->tlb_hi < KVM_GUEST_KSEG0;
1076
1077         preempt_disable();
1078
1079         /* Invalidate page table entries */
1080         kvm_trap_emul_invalidate_gva(vcpu, tlb->tlb_hi & VPN2_MASK, user);
1081
1082         /*
1083          * Probe the shadow host TLB for the entry being overwritten, if one
1084          * matches, invalidate it
1085          */
1086         kvm_mips_host_tlb_inv(vcpu, tlb->tlb_hi, user, true);
1087
1088         /* Invalidate the whole ASID on other CPUs */
1089         cpu = smp_processor_id();
1090         for_each_possible_cpu(i) {
1091                 if (i == cpu)
1092                         continue;
1093                 if (user)
1094                         set_cpu_context(i, user_mm, 0);
1095                 set_cpu_context(i, kern_mm, 0);
1096         }
1097
1098         preempt_enable();
1099 }
1100
1101 /* Write Guest TLB Entry @ Index */
1102 enum emulation_result kvm_mips_emul_tlbwi(struct kvm_vcpu *vcpu)
1103 {
1104         struct mips_coproc *cop0 = vcpu->arch.cop0;
1105         int index = kvm_read_c0_guest_index(cop0);
1106         struct kvm_mips_tlb *tlb = NULL;
1107         unsigned long pc = vcpu->arch.pc;
1108
1109         if (index < 0 || index >= KVM_MIPS_GUEST_TLB_SIZE) {
1110                 kvm_debug("%s: illegal index: %d\n", __func__, index);
1111                 kvm_debug("[%#lx] COP0_TLBWI [%d] (entryhi: %#lx, entrylo0: %#lx entrylo1: %#lx, mask: %#lx)\n",
1112                           pc, index, kvm_read_c0_guest_entryhi(cop0),
1113                           kvm_read_c0_guest_entrylo0(cop0),
1114                           kvm_read_c0_guest_entrylo1(cop0),
1115                           kvm_read_c0_guest_pagemask(cop0));
1116                 index = (index & ~0x80000000) % KVM_MIPS_GUEST_TLB_SIZE;
1117         }
1118
1119         tlb = &vcpu->arch.guest_tlb[index];
1120
1121         kvm_mips_invalidate_guest_tlb(vcpu, tlb);
1122
1123         tlb->tlb_mask = kvm_read_c0_guest_pagemask(cop0);
1124         tlb->tlb_hi = kvm_read_c0_guest_entryhi(cop0);
1125         tlb->tlb_lo[0] = kvm_read_c0_guest_entrylo0(cop0);
1126         tlb->tlb_lo[1] = kvm_read_c0_guest_entrylo1(cop0);
1127
1128         kvm_debug("[%#lx] COP0_TLBWI [%d] (entryhi: %#lx, entrylo0: %#lx entrylo1: %#lx, mask: %#lx)\n",
1129                   pc, index, kvm_read_c0_guest_entryhi(cop0),
1130                   kvm_read_c0_guest_entrylo0(cop0),
1131                   kvm_read_c0_guest_entrylo1(cop0),
1132                   kvm_read_c0_guest_pagemask(cop0));
1133
1134         return EMULATE_DONE;
1135 }
1136
1137 /* Write Guest TLB Entry @ Random Index */
1138 enum emulation_result kvm_mips_emul_tlbwr(struct kvm_vcpu *vcpu)
1139 {
1140         struct mips_coproc *cop0 = vcpu->arch.cop0;
1141         struct kvm_mips_tlb *tlb = NULL;
1142         unsigned long pc = vcpu->arch.pc;
1143         int index;
1144
1145         index = prandom_u32_max(KVM_MIPS_GUEST_TLB_SIZE);
1146         tlb = &vcpu->arch.guest_tlb[index];
1147
1148         kvm_mips_invalidate_guest_tlb(vcpu, tlb);
1149
1150         tlb->tlb_mask = kvm_read_c0_guest_pagemask(cop0);
1151         tlb->tlb_hi = kvm_read_c0_guest_entryhi(cop0);
1152         tlb->tlb_lo[0] = kvm_read_c0_guest_entrylo0(cop0);
1153         tlb->tlb_lo[1] = kvm_read_c0_guest_entrylo1(cop0);
1154
1155         kvm_debug("[%#lx] COP0_TLBWR[%d] (entryhi: %#lx, entrylo0: %#lx entrylo1: %#lx)\n",
1156                   pc, index, kvm_read_c0_guest_entryhi(cop0),
1157                   kvm_read_c0_guest_entrylo0(cop0),
1158                   kvm_read_c0_guest_entrylo1(cop0));
1159
1160         return EMULATE_DONE;
1161 }
1162
1163 enum emulation_result kvm_mips_emul_tlbp(struct kvm_vcpu *vcpu)
1164 {
1165         struct mips_coproc *cop0 = vcpu->arch.cop0;
1166         long entryhi = kvm_read_c0_guest_entryhi(cop0);
1167         unsigned long pc = vcpu->arch.pc;
1168         int index = -1;
1169
1170         index = kvm_mips_guest_tlb_lookup(vcpu, entryhi);
1171
1172         kvm_write_c0_guest_index(cop0, index);
1173
1174         kvm_debug("[%#lx] COP0_TLBP (entryhi: %#lx), index: %d\n", pc, entryhi,
1175                   index);
1176
1177         return EMULATE_DONE;
1178 }
1179
1180 /**
1181  * kvm_mips_config1_wrmask() - Find mask of writable bits in guest Config1
1182  * @vcpu:       Virtual CPU.
1183  *
1184  * Finds the mask of bits which are writable in the guest's Config1 CP0
1185  * register, by userland (currently read-only to the guest).
1186  */
1187 unsigned int kvm_mips_config1_wrmask(struct kvm_vcpu *vcpu)
1188 {
1189         unsigned int mask = 0;
1190
1191         /* Permit FPU to be present if FPU is supported */
1192         if (kvm_mips_guest_can_have_fpu(&vcpu->arch))
1193                 mask |= MIPS_CONF1_FP;
1194
1195         return mask;
1196 }
1197
1198 /**
1199  * kvm_mips_config3_wrmask() - Find mask of writable bits in guest Config3
1200  * @vcpu:       Virtual CPU.
1201  *
1202  * Finds the mask of bits which are writable in the guest's Config3 CP0
1203  * register, by userland (currently read-only to the guest).
1204  */
1205 unsigned int kvm_mips_config3_wrmask(struct kvm_vcpu *vcpu)
1206 {
1207         /* Config4 and ULRI are optional */
1208         unsigned int mask = MIPS_CONF_M | MIPS_CONF3_ULRI;
1209
1210         /* Permit MSA to be present if MSA is supported */
1211         if (kvm_mips_guest_can_have_msa(&vcpu->arch))
1212                 mask |= MIPS_CONF3_MSA;
1213
1214         return mask;
1215 }
1216
1217 /**
1218  * kvm_mips_config4_wrmask() - Find mask of writable bits in guest Config4
1219  * @vcpu:       Virtual CPU.
1220  *
1221  * Finds the mask of bits which are writable in the guest's Config4 CP0
1222  * register, by userland (currently read-only to the guest).
1223  */
1224 unsigned int kvm_mips_config4_wrmask(struct kvm_vcpu *vcpu)
1225 {
1226         /* Config5 is optional */
1227         unsigned int mask = MIPS_CONF_M;
1228
1229         /* KScrExist */
1230         mask |= 0xfc << MIPS_CONF4_KSCREXIST_SHIFT;
1231
1232         return mask;
1233 }
1234
1235 /**
1236  * kvm_mips_config5_wrmask() - Find mask of writable bits in guest Config5
1237  * @vcpu:       Virtual CPU.
1238  *
1239  * Finds the mask of bits which are writable in the guest's Config5 CP0
1240  * register, by the guest itself.
1241  */
1242 unsigned int kvm_mips_config5_wrmask(struct kvm_vcpu *vcpu)
1243 {
1244         unsigned int mask = 0;
1245
1246         /* Permit MSAEn changes if MSA supported and enabled */
1247         if (kvm_mips_guest_has_msa(&vcpu->arch))
1248                 mask |= MIPS_CONF5_MSAEN;
1249
1250         /*
1251          * Permit guest FPU mode changes if FPU is enabled and the relevant
1252          * feature exists according to FIR register.
1253          */
1254         if (kvm_mips_guest_has_fpu(&vcpu->arch)) {
1255                 if (cpu_has_fre)
1256                         mask |= MIPS_CONF5_FRE;
1257                 /* We don't support UFR or UFE */
1258         }
1259
1260         return mask;
1261 }
1262
1263 enum emulation_result kvm_mips_emulate_CP0(union mips_instruction inst,
1264                                            u32 *opc, u32 cause,
1265                                            struct kvm_run *run,
1266                                            struct kvm_vcpu *vcpu)
1267 {
1268         struct mips_coproc *cop0 = vcpu->arch.cop0;
1269         enum emulation_result er = EMULATE_DONE;
1270         u32 rt, rd, sel;
1271         unsigned long curr_pc;
1272
1273         /*
1274          * Update PC and hold onto current PC in case there is
1275          * an error and we want to rollback the PC
1276          */
1277         curr_pc = vcpu->arch.pc;
1278         er = update_pc(vcpu, cause);
1279         if (er == EMULATE_FAIL)
1280                 return er;
1281
1282         if (inst.co_format.co) {
1283                 switch (inst.co_format.func) {
1284                 case tlbr_op:   /*  Read indexed TLB entry  */
1285                         er = kvm_mips_emul_tlbr(vcpu);
1286                         break;
1287                 case tlbwi_op:  /*  Write indexed  */
1288                         er = kvm_mips_emul_tlbwi(vcpu);
1289                         break;
1290                 case tlbwr_op:  /*  Write random  */
1291                         er = kvm_mips_emul_tlbwr(vcpu);
1292                         break;
1293                 case tlbp_op:   /* TLB Probe */
1294                         er = kvm_mips_emul_tlbp(vcpu);
1295                         break;
1296                 case rfe_op:
1297                         kvm_err("!!!COP0_RFE!!!\n");
1298                         break;
1299                 case eret_op:
1300                         er = kvm_mips_emul_eret(vcpu);
1301                         goto dont_update_pc;
1302                 case wait_op:
1303                         er = kvm_mips_emul_wait(vcpu);
1304                         break;
1305                 case hypcall_op:
1306                         er = kvm_mips_emul_hypcall(vcpu, inst);
1307                         break;
1308                 }
1309         } else {
1310                 rt = inst.c0r_format.rt;
1311                 rd = inst.c0r_format.rd;
1312                 sel = inst.c0r_format.sel;
1313
1314                 switch (inst.c0r_format.rs) {
1315                 case mfc_op:
1316 #ifdef CONFIG_KVM_MIPS_DEBUG_COP0_COUNTERS
1317                         cop0->stat[rd][sel]++;
1318 #endif
1319                         /* Get reg */
1320                         if ((rd == MIPS_CP0_COUNT) && (sel == 0)) {
1321                                 vcpu->arch.gprs[rt] =
1322                                     (s32)kvm_mips_read_count(vcpu);
1323                         } else if ((rd == MIPS_CP0_ERRCTL) && (sel == 0)) {
1324                                 vcpu->arch.gprs[rt] = 0x0;
1325 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
1326                                 kvm_mips_trans_mfc0(inst, opc, vcpu);
1327 #endif
1328                         } else {
1329                                 vcpu->arch.gprs[rt] = (s32)cop0->reg[rd][sel];
1330
1331 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
1332                                 kvm_mips_trans_mfc0(inst, opc, vcpu);
1333 #endif
1334                         }
1335
1336                         trace_kvm_hwr(vcpu, KVM_TRACE_MFC0,
1337                                       KVM_TRACE_COP0(rd, sel),
1338                                       vcpu->arch.gprs[rt]);
1339                         break;
1340
1341                 case dmfc_op:
1342                         vcpu->arch.gprs[rt] = cop0->reg[rd][sel];
1343
1344                         trace_kvm_hwr(vcpu, KVM_TRACE_DMFC0,
1345                                       KVM_TRACE_COP0(rd, sel),
1346                                       vcpu->arch.gprs[rt]);
1347                         break;
1348
1349                 case mtc_op:
1350 #ifdef CONFIG_KVM_MIPS_DEBUG_COP0_COUNTERS
1351                         cop0->stat[rd][sel]++;
1352 #endif
1353                         trace_kvm_hwr(vcpu, KVM_TRACE_MTC0,
1354                                       KVM_TRACE_COP0(rd, sel),
1355                                       vcpu->arch.gprs[rt]);
1356
1357                         if ((rd == MIPS_CP0_TLB_INDEX)
1358                             && (vcpu->arch.gprs[rt] >=
1359                                 KVM_MIPS_GUEST_TLB_SIZE)) {
1360                                 kvm_err("Invalid TLB Index: %ld",
1361                                         vcpu->arch.gprs[rt]);
1362                                 er = EMULATE_FAIL;
1363                                 break;
1364                         }
1365                         if ((rd == MIPS_CP0_PRID) && (sel == 1)) {
1366                                 /*
1367                                  * Preserve core number, and keep the exception
1368                                  * base in guest KSeg0.
1369                                  */
1370                                 kvm_change_c0_guest_ebase(cop0, 0x1ffff000,
1371                                                           vcpu->arch.gprs[rt]);
1372                         } else if (rd == MIPS_CP0_TLB_HI && sel == 0) {
1373                                 kvm_mips_change_entryhi(vcpu,
1374                                                         vcpu->arch.gprs[rt]);
1375                         }
1376                         /* Are we writing to COUNT */
1377                         else if ((rd == MIPS_CP0_COUNT) && (sel == 0)) {
1378                                 kvm_mips_write_count(vcpu, vcpu->arch.gprs[rt]);
1379                                 goto done;
1380                         } else if ((rd == MIPS_CP0_COMPARE) && (sel == 0)) {
1381                                 /* If we are writing to COMPARE */
1382                                 /* Clear pending timer interrupt, if any */
1383                                 kvm_mips_write_compare(vcpu,
1384                                                        vcpu->arch.gprs[rt],
1385                                                        true);
1386                         } else if ((rd == MIPS_CP0_STATUS) && (sel == 0)) {
1387                                 unsigned int old_val, val, change;
1388
1389                                 old_val = kvm_read_c0_guest_status(cop0);
1390                                 val = vcpu->arch.gprs[rt];
1391                                 change = val ^ old_val;
1392
1393                                 /* Make sure that the NMI bit is never set */
1394                                 val &= ~ST0_NMI;
1395
1396                                 /*
1397                                  * Don't allow CU1 or FR to be set unless FPU
1398                                  * capability enabled and exists in guest
1399                                  * configuration.
1400                                  */
1401                                 if (!kvm_mips_guest_has_fpu(&vcpu->arch))
1402                                         val &= ~(ST0_CU1 | ST0_FR);
1403
1404                                 /*
1405                                  * Also don't allow FR to be set if host doesn't
1406                                  * support it.
1407                                  */
1408                                 if (!(current_cpu_data.fpu_id & MIPS_FPIR_F64))
1409                                         val &= ~ST0_FR;
1410
1411
1412                                 /* Handle changes in FPU mode */
1413                                 preempt_disable();
1414
1415                                 /*
1416                                  * FPU and Vector register state is made
1417                                  * UNPREDICTABLE by a change of FR, so don't
1418                                  * even bother saving it.
1419                                  */
1420                                 if (change & ST0_FR)
1421                                         kvm_drop_fpu(vcpu);
1422
1423                                 /*
1424                                  * If MSA state is already live, it is undefined
1425                                  * how it interacts with FR=0 FPU state, and we
1426                                  * don't want to hit reserved instruction
1427                                  * exceptions trying to save the MSA state later
1428                                  * when CU=1 && FR=1, so play it safe and save
1429                                  * it first.
1430                                  */
1431                                 if (change & ST0_CU1 && !(val & ST0_FR) &&
1432                                     vcpu->arch.aux_inuse & KVM_MIPS_AUX_MSA)
1433                                         kvm_lose_fpu(vcpu);
1434
1435                                 /*
1436                                  * Propagate CU1 (FPU enable) changes
1437                                  * immediately if the FPU context is already
1438                                  * loaded. When disabling we leave the context
1439                                  * loaded so it can be quickly enabled again in
1440                                  * the near future.
1441                                  */
1442                                 if (change & ST0_CU1 &&
1443                                     vcpu->arch.aux_inuse & KVM_MIPS_AUX_FPU)
1444                                         change_c0_status(ST0_CU1, val);
1445
1446                                 preempt_enable();
1447
1448                                 kvm_write_c0_guest_status(cop0, val);
1449
1450 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
1451                                 /*
1452                                  * If FPU present, we need CU1/FR bits to take
1453                                  * effect fairly soon.
1454                                  */
1455                                 if (!kvm_mips_guest_has_fpu(&vcpu->arch))
1456                                         kvm_mips_trans_mtc0(inst, opc, vcpu);
1457 #endif
1458                         } else if ((rd == MIPS_CP0_CONFIG) && (sel == 5)) {
1459                                 unsigned int old_val, val, change, wrmask;
1460
1461                                 old_val = kvm_read_c0_guest_config5(cop0);
1462                                 val = vcpu->arch.gprs[rt];
1463
1464                                 /* Only a few bits are writable in Config5 */
1465                                 wrmask = kvm_mips_config5_wrmask(vcpu);
1466                                 change = (val ^ old_val) & wrmask;
1467                                 val = old_val ^ change;
1468
1469
1470                                 /* Handle changes in FPU/MSA modes */
1471                                 preempt_disable();
1472
1473                                 /*
1474                                  * Propagate FRE changes immediately if the FPU
1475                                  * context is already loaded.
1476                                  */
1477                                 if (change & MIPS_CONF5_FRE &&
1478                                     vcpu->arch.aux_inuse & KVM_MIPS_AUX_FPU)
1479                                         change_c0_config5(MIPS_CONF5_FRE, val);
1480
1481                                 /*
1482                                  * Propagate MSAEn changes immediately if the
1483                                  * MSA context is already loaded. When disabling
1484                                  * we leave the context loaded so it can be
1485                                  * quickly enabled again in the near future.
1486                                  */
1487                                 if (change & MIPS_CONF5_MSAEN &&
1488                                     vcpu->arch.aux_inuse & KVM_MIPS_AUX_MSA)
1489                                         change_c0_config5(MIPS_CONF5_MSAEN,
1490                                                           val);
1491
1492                                 preempt_enable();
1493
1494                                 kvm_write_c0_guest_config5(cop0, val);
1495                         } else if ((rd == MIPS_CP0_CAUSE) && (sel == 0)) {
1496                                 u32 old_cause, new_cause;
1497
1498                                 old_cause = kvm_read_c0_guest_cause(cop0);
1499                                 new_cause = vcpu->arch.gprs[rt];
1500                                 /* Update R/W bits */
1501                                 kvm_change_c0_guest_cause(cop0, 0x08800300,
1502                                                           new_cause);
1503                                 /* DC bit enabling/disabling timer? */
1504                                 if ((old_cause ^ new_cause) & CAUSEF_DC) {
1505                                         if (new_cause & CAUSEF_DC)
1506                                                 kvm_mips_count_disable_cause(vcpu);
1507                                         else
1508                                                 kvm_mips_count_enable_cause(vcpu);
1509                                 }
1510                         } else if ((rd == MIPS_CP0_HWRENA) && (sel == 0)) {
1511                                 u32 mask = MIPS_HWRENA_CPUNUM |
1512                                            MIPS_HWRENA_SYNCISTEP |
1513                                            MIPS_HWRENA_CC |
1514                                            MIPS_HWRENA_CCRES;
1515
1516                                 if (kvm_read_c0_guest_config3(cop0) &
1517                                     MIPS_CONF3_ULRI)
1518                                         mask |= MIPS_HWRENA_ULR;
1519                                 cop0->reg[rd][sel] = vcpu->arch.gprs[rt] & mask;
1520                         } else {
1521                                 cop0->reg[rd][sel] = vcpu->arch.gprs[rt];
1522 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
1523                                 kvm_mips_trans_mtc0(inst, opc, vcpu);
1524 #endif
1525                         }
1526                         break;
1527
1528                 case dmtc_op:
1529                         kvm_err("!!!!!!![%#lx]dmtc_op: rt: %d, rd: %d, sel: %d!!!!!!\n",
1530                                 vcpu->arch.pc, rt, rd, sel);
1531                         trace_kvm_hwr(vcpu, KVM_TRACE_DMTC0,
1532                                       KVM_TRACE_COP0(rd, sel),
1533                                       vcpu->arch.gprs[rt]);
1534                         er = EMULATE_FAIL;
1535                         break;
1536
1537                 case mfmc0_op:
1538 #ifdef KVM_MIPS_DEBUG_COP0_COUNTERS
1539                         cop0->stat[MIPS_CP0_STATUS][0]++;
1540 #endif
1541                         if (rt != 0)
1542                                 vcpu->arch.gprs[rt] =
1543                                     kvm_read_c0_guest_status(cop0);
1544                         /* EI */
1545                         if (inst.mfmc0_format.sc) {
1546                                 kvm_debug("[%#lx] mfmc0_op: EI\n",
1547                                           vcpu->arch.pc);
1548                                 kvm_set_c0_guest_status(cop0, ST0_IE);
1549                         } else {
1550                                 kvm_debug("[%#lx] mfmc0_op: DI\n",
1551                                           vcpu->arch.pc);
1552                                 kvm_clear_c0_guest_status(cop0, ST0_IE);
1553                         }
1554
1555                         break;
1556
1557                 case wrpgpr_op:
1558                         {
1559                                 u32 css = cop0->reg[MIPS_CP0_STATUS][2] & 0xf;
1560                                 u32 pss =
1561                                     (cop0->reg[MIPS_CP0_STATUS][2] >> 6) & 0xf;
1562                                 /*
1563                                  * We don't support any shadow register sets, so
1564                                  * SRSCtl[PSS] == SRSCtl[CSS] = 0
1565                                  */
1566                                 if (css || pss) {
1567                                         er = EMULATE_FAIL;
1568                                         break;
1569                                 }
1570                                 kvm_debug("WRPGPR[%d][%d] = %#lx\n", pss, rd,
1571                                           vcpu->arch.gprs[rt]);
1572                                 vcpu->arch.gprs[rd] = vcpu->arch.gprs[rt];
1573                         }
1574                         break;
1575                 default:
1576                         kvm_err("[%#lx]MachEmulateCP0: unsupported COP0, copz: 0x%x\n",
1577                                 vcpu->arch.pc, inst.c0r_format.rs);
1578                         er = EMULATE_FAIL;
1579                         break;
1580                 }
1581         }
1582
1583 done:
1584         /* Rollback PC only if emulation was unsuccessful */
1585         if (er == EMULATE_FAIL)
1586                 vcpu->arch.pc = curr_pc;
1587
1588 dont_update_pc:
1589         /*
1590          * This is for special instructions whose emulation
1591          * updates the PC, so do not overwrite the PC under
1592          * any circumstances
1593          */
1594
1595         return er;
1596 }
1597
1598 enum emulation_result kvm_mips_emulate_store(union mips_instruction inst,
1599                                              u32 cause,
1600                                              struct kvm_run *run,
1601                                              struct kvm_vcpu *vcpu)
1602 {
1603         enum emulation_result er;
1604         u32 rt;
1605         void *data = run->mmio.data;
1606         unsigned long curr_pc;
1607
1608         /*
1609          * Update PC and hold onto current PC in case there is
1610          * an error and we want to rollback the PC
1611          */
1612         curr_pc = vcpu->arch.pc;
1613         er = update_pc(vcpu, cause);
1614         if (er == EMULATE_FAIL)
1615                 return er;
1616
1617         rt = inst.i_format.rt;
1618
1619         run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
1620                                                 vcpu->arch.host_cp0_badvaddr);
1621         if (run->mmio.phys_addr == KVM_INVALID_ADDR)
1622                 goto out_fail;
1623
1624         switch (inst.i_format.opcode) {
1625 #if defined(CONFIG_64BIT) && defined(CONFIG_KVM_MIPS_VZ)
1626         case sd_op:
1627                 run->mmio.len = 8;
1628                 *(u64 *)data = vcpu->arch.gprs[rt];
1629
1630                 kvm_debug("[%#lx] OP_SD: eaddr: %#lx, gpr: %#lx, data: %#llx\n",
1631                           vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
1632                           vcpu->arch.gprs[rt], *(u64 *)data);
1633                 break;
1634 #endif
1635
1636         case sw_op:
1637                 run->mmio.len = 4;
1638                 *(u32 *)data = vcpu->arch.gprs[rt];
1639
1640                 kvm_debug("[%#lx] OP_SW: eaddr: %#lx, gpr: %#lx, data: %#x\n",
1641                           vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
1642                           vcpu->arch.gprs[rt], *(u32 *)data);
1643                 break;
1644
1645         case sh_op:
1646                 run->mmio.len = 2;
1647                 *(u16 *)data = vcpu->arch.gprs[rt];
1648
1649                 kvm_debug("[%#lx] OP_SH: eaddr: %#lx, gpr: %#lx, data: %#x\n",
1650                           vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
1651                           vcpu->arch.gprs[rt], *(u16 *)data);
1652                 break;
1653
1654         case sb_op:
1655                 run->mmio.len = 1;
1656                 *(u8 *)data = vcpu->arch.gprs[rt];
1657
1658                 kvm_debug("[%#lx] OP_SB: eaddr: %#lx, gpr: %#lx, data: %#x\n",
1659                           vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
1660                           vcpu->arch.gprs[rt], *(u8 *)data);
1661                 break;
1662
1663         default:
1664                 kvm_err("Store not yet supported (inst=0x%08x)\n",
1665                         inst.word);
1666                 goto out_fail;
1667         }
1668
1669         run->mmio.is_write = 1;
1670         vcpu->mmio_needed = 1;
1671         vcpu->mmio_is_write = 1;
1672         return EMULATE_DO_MMIO;
1673
1674 out_fail:
1675         /* Rollback PC if emulation was unsuccessful */
1676         vcpu->arch.pc = curr_pc;
1677         return EMULATE_FAIL;
1678 }
1679
1680 enum emulation_result kvm_mips_emulate_load(union mips_instruction inst,
1681                                             u32 cause, struct kvm_run *run,
1682                                             struct kvm_vcpu *vcpu)
1683 {
1684         enum emulation_result er;
1685         unsigned long curr_pc;
1686         u32 op, rt;
1687
1688         rt = inst.i_format.rt;
1689         op = inst.i_format.opcode;
1690
1691         /*
1692          * Find the resume PC now while we have safe and easy access to the
1693          * prior branch instruction, and save it for
1694          * kvm_mips_complete_mmio_load() to restore later.
1695          */
1696         curr_pc = vcpu->arch.pc;
1697         er = update_pc(vcpu, cause);
1698         if (er == EMULATE_FAIL)
1699                 return er;
1700         vcpu->arch.io_pc = vcpu->arch.pc;
1701         vcpu->arch.pc = curr_pc;
1702
1703         vcpu->arch.io_gpr = rt;
1704
1705         run->mmio.phys_addr = kvm_mips_callbacks->gva_to_gpa(
1706                                                 vcpu->arch.host_cp0_badvaddr);
1707         if (run->mmio.phys_addr == KVM_INVALID_ADDR)
1708                 return EMULATE_FAIL;
1709
1710         vcpu->mmio_needed = 2;  /* signed */
1711         switch (op) {
1712 #if defined(CONFIG_64BIT) && defined(CONFIG_KVM_MIPS_VZ)
1713         case ld_op:
1714                 run->mmio.len = 8;
1715                 break;
1716
1717         case lwu_op:
1718                 vcpu->mmio_needed = 1;  /* unsigned */
1719                 /* fall through */
1720 #endif
1721         case lw_op:
1722                 run->mmio.len = 4;
1723                 break;
1724
1725         case lhu_op:
1726                 vcpu->mmio_needed = 1;  /* unsigned */
1727                 /* fall through */
1728         case lh_op:
1729                 run->mmio.len = 2;
1730                 break;
1731
1732         case lbu_op:
1733                 vcpu->mmio_needed = 1;  /* unsigned */
1734                 /* fall through */
1735         case lb_op:
1736                 run->mmio.len = 1;
1737                 break;
1738
1739         default:
1740                 kvm_err("Load not yet supported (inst=0x%08x)\n",
1741                         inst.word);
1742                 vcpu->mmio_needed = 0;
1743                 return EMULATE_FAIL;
1744         }
1745
1746         run->mmio.is_write = 0;
1747         vcpu->mmio_is_write = 0;
1748         return EMULATE_DO_MMIO;
1749 }
1750
1751 #ifndef CONFIG_KVM_MIPS_VZ
1752 static enum emulation_result kvm_mips_guest_cache_op(int (*fn)(unsigned long),
1753                                                      unsigned long curr_pc,
1754                                                      unsigned long addr,
1755                                                      struct kvm_run *run,
1756                                                      struct kvm_vcpu *vcpu,
1757                                                      u32 cause)
1758 {
1759         int err;
1760
1761         for (;;) {
1762                 /* Carefully attempt the cache operation */
1763                 kvm_trap_emul_gva_lockless_begin(vcpu);
1764                 err = fn(addr);
1765                 kvm_trap_emul_gva_lockless_end(vcpu);
1766
1767                 if (likely(!err))
1768                         return EMULATE_DONE;
1769
1770                 /*
1771                  * Try to handle the fault and retry, maybe we just raced with a
1772                  * GVA invalidation.
1773                  */
1774                 switch (kvm_trap_emul_gva_fault(vcpu, addr, false)) {
1775                 case KVM_MIPS_GVA:
1776                 case KVM_MIPS_GPA:
1777                         /* bad virtual or physical address */
1778                         return EMULATE_FAIL;
1779                 case KVM_MIPS_TLB:
1780                         /* no matching guest TLB */
1781                         vcpu->arch.host_cp0_badvaddr = addr;
1782                         vcpu->arch.pc = curr_pc;
1783                         kvm_mips_emulate_tlbmiss_ld(cause, NULL, run, vcpu);
1784                         return EMULATE_EXCEPT;
1785                 case KVM_MIPS_TLBINV:
1786                         /* invalid matching guest TLB */
1787                         vcpu->arch.host_cp0_badvaddr = addr;
1788                         vcpu->arch.pc = curr_pc;
1789                         kvm_mips_emulate_tlbinv_ld(cause, NULL, run, vcpu);
1790                         return EMULATE_EXCEPT;
1791                 default:
1792                         break;
1793                 };
1794         }
1795 }
1796
1797 enum emulation_result kvm_mips_emulate_cache(union mips_instruction inst,
1798                                              u32 *opc, u32 cause,
1799                                              struct kvm_run *run,
1800                                              struct kvm_vcpu *vcpu)
1801 {
1802         enum emulation_result er = EMULATE_DONE;
1803         u32 cache, op_inst, op, base;
1804         s16 offset;
1805         struct kvm_vcpu_arch *arch = &vcpu->arch;
1806         unsigned long va;
1807         unsigned long curr_pc;
1808
1809         /*
1810          * Update PC and hold onto current PC in case there is
1811          * an error and we want to rollback the PC
1812          */
1813         curr_pc = vcpu->arch.pc;
1814         er = update_pc(vcpu, cause);
1815         if (er == EMULATE_FAIL)
1816                 return er;
1817
1818         base = inst.i_format.rs;
1819         op_inst = inst.i_format.rt;
1820         if (cpu_has_mips_r6)
1821                 offset = inst.spec3_format.simmediate;
1822         else
1823                 offset = inst.i_format.simmediate;
1824         cache = op_inst & CacheOp_Cache;
1825         op = op_inst & CacheOp_Op;
1826
1827         va = arch->gprs[base] + offset;
1828
1829         kvm_debug("CACHE (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
1830                   cache, op, base, arch->gprs[base], offset);
1831
1832         /*
1833          * Treat INDEX_INV as a nop, basically issued by Linux on startup to
1834          * invalidate the caches entirely by stepping through all the
1835          * ways/indexes
1836          */
1837         if (op == Index_Writeback_Inv) {
1838                 kvm_debug("@ %#lx/%#lx CACHE (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
1839                           vcpu->arch.pc, vcpu->arch.gprs[31], cache, op, base,
1840                           arch->gprs[base], offset);
1841
1842                 if (cache == Cache_D) {
1843 #ifdef CONFIG_CPU_R4K_CACHE_TLB
1844                         r4k_blast_dcache();
1845 #else
1846                         switch (boot_cpu_type()) {
1847                         case CPU_CAVIUM_OCTEON3:
1848                                 /* locally flush icache */
1849                                 local_flush_icache_range(0, 0);
1850                                 break;
1851                         default:
1852                                 __flush_cache_all();
1853                                 break;
1854                         }
1855 #endif
1856                 } else if (cache == Cache_I) {
1857 #ifdef CONFIG_CPU_R4K_CACHE_TLB
1858                         r4k_blast_icache();
1859 #else
1860                         switch (boot_cpu_type()) {
1861                         case CPU_CAVIUM_OCTEON3:
1862                                 /* locally flush icache */
1863                                 local_flush_icache_range(0, 0);
1864                                 break;
1865                         default:
1866                                 flush_icache_all();
1867                                 break;
1868                         }
1869 #endif
1870                 } else {
1871                         kvm_err("%s: unsupported CACHE INDEX operation\n",
1872                                 __func__);
1873                         return EMULATE_FAIL;
1874                 }
1875
1876 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
1877                 kvm_mips_trans_cache_index(inst, opc, vcpu);
1878 #endif
1879                 goto done;
1880         }
1881
1882         /* XXXKYMA: Only a subset of cache ops are supported, used by Linux */
1883         if (op_inst == Hit_Writeback_Inv_D || op_inst == Hit_Invalidate_D) {
1884                 /*
1885                  * Perform the dcache part of icache synchronisation on the
1886                  * guest's behalf.
1887                  */
1888                 er = kvm_mips_guest_cache_op(protected_writeback_dcache_line,
1889                                              curr_pc, va, run, vcpu, cause);
1890                 if (er != EMULATE_DONE)
1891                         goto done;
1892 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
1893                 /*
1894                  * Replace the CACHE instruction, with a SYNCI, not the same,
1895                  * but avoids a trap
1896                  */
1897                 kvm_mips_trans_cache_va(inst, opc, vcpu);
1898 #endif
1899         } else if (op_inst == Hit_Invalidate_I) {
1900                 /* Perform the icache synchronisation on the guest's behalf */
1901                 er = kvm_mips_guest_cache_op(protected_writeback_dcache_line,
1902                                              curr_pc, va, run, vcpu, cause);
1903                 if (er != EMULATE_DONE)
1904                         goto done;
1905                 er = kvm_mips_guest_cache_op(protected_flush_icache_line,
1906                                              curr_pc, va, run, vcpu, cause);
1907                 if (er != EMULATE_DONE)
1908                         goto done;
1909
1910 #ifdef CONFIG_KVM_MIPS_DYN_TRANS
1911                 /* Replace the CACHE instruction, with a SYNCI */
1912                 kvm_mips_trans_cache_va(inst, opc, vcpu);
1913 #endif
1914         } else {
1915                 kvm_err("NO-OP CACHE (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
1916                         cache, op, base, arch->gprs[base], offset);
1917                 er = EMULATE_FAIL;
1918         }
1919
1920 done:
1921         /* Rollback PC only if emulation was unsuccessful */
1922         if (er == EMULATE_FAIL)
1923                 vcpu->arch.pc = curr_pc;
1924         /* Guest exception needs guest to resume */
1925         if (er == EMULATE_EXCEPT)
1926                 er = EMULATE_DONE;
1927
1928         return er;
1929 }
1930
1931 enum emulation_result kvm_mips_emulate_inst(u32 cause, u32 *opc,
1932                                             struct kvm_run *run,
1933                                             struct kvm_vcpu *vcpu)
1934 {
1935         union mips_instruction inst;
1936         enum emulation_result er = EMULATE_DONE;
1937         int err;
1938
1939         /* Fetch the instruction. */
1940         if (cause & CAUSEF_BD)
1941                 opc += 1;
1942         err = kvm_get_badinstr(opc, vcpu, &inst.word);
1943         if (err)
1944                 return EMULATE_FAIL;
1945
1946         switch (inst.r_format.opcode) {
1947         case cop0_op:
1948                 er = kvm_mips_emulate_CP0(inst, opc, cause, run, vcpu);
1949                 break;
1950
1951 #ifndef CONFIG_CPU_MIPSR6
1952         case cache_op:
1953                 ++vcpu->stat.cache_exits;
1954                 trace_kvm_exit(vcpu, KVM_TRACE_EXIT_CACHE);
1955                 er = kvm_mips_emulate_cache(inst, opc, cause, run, vcpu);
1956                 break;
1957 #else
1958         case spec3_op:
1959                 switch (inst.spec3_format.func) {
1960                 case cache6_op:
1961                         ++vcpu->stat.cache_exits;
1962                         trace_kvm_exit(vcpu, KVM_TRACE_EXIT_CACHE);
1963                         er = kvm_mips_emulate_cache(inst, opc, cause, run,
1964                                                     vcpu);
1965                         break;
1966                 default:
1967                         goto unknown;
1968                 };
1969                 break;
1970 unknown:
1971 #endif
1972
1973         default:
1974                 kvm_err("Instruction emulation not supported (%p/%#x)\n", opc,
1975                         inst.word);
1976                 kvm_arch_vcpu_dump_regs(vcpu);
1977                 er = EMULATE_FAIL;
1978                 break;
1979         }
1980
1981         return er;
1982 }
1983 #endif /* CONFIG_KVM_MIPS_VZ */
1984
1985 /**
1986  * kvm_mips_guest_exception_base() - Find guest exception vector base address.
1987  *
1988  * Returns:     The base address of the current guest exception vector, taking
1989  *              both Guest.CP0_Status.BEV and Guest.CP0_EBase into account.
1990  */
1991 long kvm_mips_guest_exception_base(struct kvm_vcpu *vcpu)
1992 {
1993         struct mips_coproc *cop0 = vcpu->arch.cop0;
1994
1995         if (kvm_read_c0_guest_status(cop0) & ST0_BEV)
1996                 return KVM_GUEST_CKSEG1ADDR(0x1fc00200);
1997         else
1998                 return kvm_read_c0_guest_ebase(cop0) & MIPS_EBASE_BASE;
1999 }
2000
2001 enum emulation_result kvm_mips_emulate_syscall(u32 cause,
2002                                                u32 *opc,
2003                                                struct kvm_run *run,
2004                                                struct kvm_vcpu *vcpu)
2005 {
2006         struct mips_coproc *cop0 = vcpu->arch.cop0;
2007         struct kvm_vcpu_arch *arch = &vcpu->arch;
2008         enum emulation_result er = EMULATE_DONE;
2009
2010         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2011                 /* save old pc */
2012                 kvm_write_c0_guest_epc(cop0, arch->pc);
2013                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2014
2015                 if (cause & CAUSEF_BD)
2016                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2017                 else
2018                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2019
2020                 kvm_debug("Delivering SYSCALL @ pc %#lx\n", arch->pc);
2021
2022                 kvm_change_c0_guest_cause(cop0, (0xff),
2023                                           (EXCCODE_SYS << CAUSEB_EXCCODE));
2024
2025                 /* Set PC to the exception entry point */
2026                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2027
2028         } else {
2029                 kvm_err("Trying to deliver SYSCALL when EXL is already set\n");
2030                 er = EMULATE_FAIL;
2031         }
2032
2033         return er;
2034 }
2035
2036 enum emulation_result kvm_mips_emulate_tlbmiss_ld(u32 cause,
2037                                                   u32 *opc,
2038                                                   struct kvm_run *run,
2039                                                   struct kvm_vcpu *vcpu)
2040 {
2041         struct mips_coproc *cop0 = vcpu->arch.cop0;
2042         struct kvm_vcpu_arch *arch = &vcpu->arch;
2043         unsigned long entryhi = (vcpu->arch.  host_cp0_badvaddr & VPN2_MASK) |
2044                         (kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
2045
2046         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2047                 /* save old pc */
2048                 kvm_write_c0_guest_epc(cop0, arch->pc);
2049                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2050
2051                 if (cause & CAUSEF_BD)
2052                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2053                 else
2054                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2055
2056                 kvm_debug("[EXL == 0] delivering TLB MISS @ pc %#lx\n",
2057                           arch->pc);
2058
2059                 /* set pc to the exception entry point */
2060                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x0;
2061
2062         } else {
2063                 kvm_debug("[EXL == 1] delivering TLB MISS @ pc %#lx\n",
2064                           arch->pc);
2065
2066                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2067         }
2068
2069         kvm_change_c0_guest_cause(cop0, (0xff),
2070                                   (EXCCODE_TLBL << CAUSEB_EXCCODE));
2071
2072         /* setup badvaddr, context and entryhi registers for the guest */
2073         kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
2074         /* XXXKYMA: is the context register used by linux??? */
2075         kvm_write_c0_guest_entryhi(cop0, entryhi);
2076
2077         return EMULATE_DONE;
2078 }
2079
2080 enum emulation_result kvm_mips_emulate_tlbinv_ld(u32 cause,
2081                                                  u32 *opc,
2082                                                  struct kvm_run *run,
2083                                                  struct kvm_vcpu *vcpu)
2084 {
2085         struct mips_coproc *cop0 = vcpu->arch.cop0;
2086         struct kvm_vcpu_arch *arch = &vcpu->arch;
2087         unsigned long entryhi =
2088                 (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
2089                 (kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
2090
2091         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2092                 /* save old pc */
2093                 kvm_write_c0_guest_epc(cop0, arch->pc);
2094                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2095
2096                 if (cause & CAUSEF_BD)
2097                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2098                 else
2099                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2100
2101                 kvm_debug("[EXL == 0] delivering TLB INV @ pc %#lx\n",
2102                           arch->pc);
2103         } else {
2104                 kvm_debug("[EXL == 1] delivering TLB MISS @ pc %#lx\n",
2105                           arch->pc);
2106         }
2107
2108         /* set pc to the exception entry point */
2109         arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2110
2111         kvm_change_c0_guest_cause(cop0, (0xff),
2112                                   (EXCCODE_TLBL << CAUSEB_EXCCODE));
2113
2114         /* setup badvaddr, context and entryhi registers for the guest */
2115         kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
2116         /* XXXKYMA: is the context register used by linux??? */
2117         kvm_write_c0_guest_entryhi(cop0, entryhi);
2118
2119         return EMULATE_DONE;
2120 }
2121
2122 enum emulation_result kvm_mips_emulate_tlbmiss_st(u32 cause,
2123                                                   u32 *opc,
2124                                                   struct kvm_run *run,
2125                                                   struct kvm_vcpu *vcpu)
2126 {
2127         struct mips_coproc *cop0 = vcpu->arch.cop0;
2128         struct kvm_vcpu_arch *arch = &vcpu->arch;
2129         unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
2130                         (kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
2131
2132         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2133                 /* save old pc */
2134                 kvm_write_c0_guest_epc(cop0, arch->pc);
2135                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2136
2137                 if (cause & CAUSEF_BD)
2138                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2139                 else
2140                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2141
2142                 kvm_debug("[EXL == 0] Delivering TLB MISS @ pc %#lx\n",
2143                           arch->pc);
2144
2145                 /* Set PC to the exception entry point */
2146                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x0;
2147         } else {
2148                 kvm_debug("[EXL == 1] Delivering TLB MISS @ pc %#lx\n",
2149                           arch->pc);
2150                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2151         }
2152
2153         kvm_change_c0_guest_cause(cop0, (0xff),
2154                                   (EXCCODE_TLBS << CAUSEB_EXCCODE));
2155
2156         /* setup badvaddr, context and entryhi registers for the guest */
2157         kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
2158         /* XXXKYMA: is the context register used by linux??? */
2159         kvm_write_c0_guest_entryhi(cop0, entryhi);
2160
2161         return EMULATE_DONE;
2162 }
2163
2164 enum emulation_result kvm_mips_emulate_tlbinv_st(u32 cause,
2165                                                  u32 *opc,
2166                                                  struct kvm_run *run,
2167                                                  struct kvm_vcpu *vcpu)
2168 {
2169         struct mips_coproc *cop0 = vcpu->arch.cop0;
2170         struct kvm_vcpu_arch *arch = &vcpu->arch;
2171         unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
2172                 (kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
2173
2174         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2175                 /* save old pc */
2176                 kvm_write_c0_guest_epc(cop0, arch->pc);
2177                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2178
2179                 if (cause & CAUSEF_BD)
2180                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2181                 else
2182                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2183
2184                 kvm_debug("[EXL == 0] Delivering TLB MISS @ pc %#lx\n",
2185                           arch->pc);
2186         } else {
2187                 kvm_debug("[EXL == 1] Delivering TLB MISS @ pc %#lx\n",
2188                           arch->pc);
2189         }
2190
2191         /* Set PC to the exception entry point */
2192         arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2193
2194         kvm_change_c0_guest_cause(cop0, (0xff),
2195                                   (EXCCODE_TLBS << CAUSEB_EXCCODE));
2196
2197         /* setup badvaddr, context and entryhi registers for the guest */
2198         kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
2199         /* XXXKYMA: is the context register used by linux??? */
2200         kvm_write_c0_guest_entryhi(cop0, entryhi);
2201
2202         return EMULATE_DONE;
2203 }
2204
2205 enum emulation_result kvm_mips_emulate_tlbmod(u32 cause,
2206                                               u32 *opc,
2207                                               struct kvm_run *run,
2208                                               struct kvm_vcpu *vcpu)
2209 {
2210         struct mips_coproc *cop0 = vcpu->arch.cop0;
2211         unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
2212                         (kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID);
2213         struct kvm_vcpu_arch *arch = &vcpu->arch;
2214
2215         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2216                 /* save old pc */
2217                 kvm_write_c0_guest_epc(cop0, arch->pc);
2218                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2219
2220                 if (cause & CAUSEF_BD)
2221                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2222                 else
2223                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2224
2225                 kvm_debug("[EXL == 0] Delivering TLB MOD @ pc %#lx\n",
2226                           arch->pc);
2227         } else {
2228                 kvm_debug("[EXL == 1] Delivering TLB MOD @ pc %#lx\n",
2229                           arch->pc);
2230         }
2231
2232         arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2233
2234         kvm_change_c0_guest_cause(cop0, (0xff),
2235                                   (EXCCODE_MOD << CAUSEB_EXCCODE));
2236
2237         /* setup badvaddr, context and entryhi registers for the guest */
2238         kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
2239         /* XXXKYMA: is the context register used by linux??? */
2240         kvm_write_c0_guest_entryhi(cop0, entryhi);
2241
2242         return EMULATE_DONE;
2243 }
2244
2245 enum emulation_result kvm_mips_emulate_fpu_exc(u32 cause,
2246                                                u32 *opc,
2247                                                struct kvm_run *run,
2248                                                struct kvm_vcpu *vcpu)
2249 {
2250         struct mips_coproc *cop0 = vcpu->arch.cop0;
2251         struct kvm_vcpu_arch *arch = &vcpu->arch;
2252
2253         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2254                 /* save old pc */
2255                 kvm_write_c0_guest_epc(cop0, arch->pc);
2256                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2257
2258                 if (cause & CAUSEF_BD)
2259                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2260                 else
2261                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2262
2263         }
2264
2265         arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2266
2267         kvm_change_c0_guest_cause(cop0, (0xff),
2268                                   (EXCCODE_CPU << CAUSEB_EXCCODE));
2269         kvm_change_c0_guest_cause(cop0, (CAUSEF_CE), (0x1 << CAUSEB_CE));
2270
2271         return EMULATE_DONE;
2272 }
2273
2274 enum emulation_result kvm_mips_emulate_ri_exc(u32 cause,
2275                                               u32 *opc,
2276                                               struct kvm_run *run,
2277                                               struct kvm_vcpu *vcpu)
2278 {
2279         struct mips_coproc *cop0 = vcpu->arch.cop0;
2280         struct kvm_vcpu_arch *arch = &vcpu->arch;
2281         enum emulation_result er = EMULATE_DONE;
2282
2283         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2284                 /* save old pc */
2285                 kvm_write_c0_guest_epc(cop0, arch->pc);
2286                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2287
2288                 if (cause & CAUSEF_BD)
2289                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2290                 else
2291                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2292
2293                 kvm_debug("Delivering RI @ pc %#lx\n", arch->pc);
2294
2295                 kvm_change_c0_guest_cause(cop0, (0xff),
2296                                           (EXCCODE_RI << CAUSEB_EXCCODE));
2297
2298                 /* Set PC to the exception entry point */
2299                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2300
2301         } else {
2302                 kvm_err("Trying to deliver RI when EXL is already set\n");
2303                 er = EMULATE_FAIL;
2304         }
2305
2306         return er;
2307 }
2308
2309 enum emulation_result kvm_mips_emulate_bp_exc(u32 cause,
2310                                               u32 *opc,
2311                                               struct kvm_run *run,
2312                                               struct kvm_vcpu *vcpu)
2313 {
2314         struct mips_coproc *cop0 = vcpu->arch.cop0;
2315         struct kvm_vcpu_arch *arch = &vcpu->arch;
2316         enum emulation_result er = EMULATE_DONE;
2317
2318         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2319                 /* save old pc */
2320                 kvm_write_c0_guest_epc(cop0, arch->pc);
2321                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2322
2323                 if (cause & CAUSEF_BD)
2324                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2325                 else
2326                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2327
2328                 kvm_debug("Delivering BP @ pc %#lx\n", arch->pc);
2329
2330                 kvm_change_c0_guest_cause(cop0, (0xff),
2331                                           (EXCCODE_BP << CAUSEB_EXCCODE));
2332
2333                 /* Set PC to the exception entry point */
2334                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2335
2336         } else {
2337                 kvm_err("Trying to deliver BP when EXL is already set\n");
2338                 er = EMULATE_FAIL;
2339         }
2340
2341         return er;
2342 }
2343
2344 enum emulation_result kvm_mips_emulate_trap_exc(u32 cause,
2345                                                 u32 *opc,
2346                                                 struct kvm_run *run,
2347                                                 struct kvm_vcpu *vcpu)
2348 {
2349         struct mips_coproc *cop0 = vcpu->arch.cop0;
2350         struct kvm_vcpu_arch *arch = &vcpu->arch;
2351         enum emulation_result er = EMULATE_DONE;
2352
2353         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2354                 /* save old pc */
2355                 kvm_write_c0_guest_epc(cop0, arch->pc);
2356                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2357
2358                 if (cause & CAUSEF_BD)
2359                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2360                 else
2361                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2362
2363                 kvm_debug("Delivering TRAP @ pc %#lx\n", arch->pc);
2364
2365                 kvm_change_c0_guest_cause(cop0, (0xff),
2366                                           (EXCCODE_TR << CAUSEB_EXCCODE));
2367
2368                 /* Set PC to the exception entry point */
2369                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2370
2371         } else {
2372                 kvm_err("Trying to deliver TRAP when EXL is already set\n");
2373                 er = EMULATE_FAIL;
2374         }
2375
2376         return er;
2377 }
2378
2379 enum emulation_result kvm_mips_emulate_msafpe_exc(u32 cause,
2380                                                   u32 *opc,
2381                                                   struct kvm_run *run,
2382                                                   struct kvm_vcpu *vcpu)
2383 {
2384         struct mips_coproc *cop0 = vcpu->arch.cop0;
2385         struct kvm_vcpu_arch *arch = &vcpu->arch;
2386         enum emulation_result er = EMULATE_DONE;
2387
2388         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2389                 /* save old pc */
2390                 kvm_write_c0_guest_epc(cop0, arch->pc);
2391                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2392
2393                 if (cause & CAUSEF_BD)
2394                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2395                 else
2396                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2397
2398                 kvm_debug("Delivering MSAFPE @ pc %#lx\n", arch->pc);
2399
2400                 kvm_change_c0_guest_cause(cop0, (0xff),
2401                                           (EXCCODE_MSAFPE << CAUSEB_EXCCODE));
2402
2403                 /* Set PC to the exception entry point */
2404                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2405
2406         } else {
2407                 kvm_err("Trying to deliver MSAFPE when EXL is already set\n");
2408                 er = EMULATE_FAIL;
2409         }
2410
2411         return er;
2412 }
2413
2414 enum emulation_result kvm_mips_emulate_fpe_exc(u32 cause,
2415                                                u32 *opc,
2416                                                struct kvm_run *run,
2417                                                struct kvm_vcpu *vcpu)
2418 {
2419         struct mips_coproc *cop0 = vcpu->arch.cop0;
2420         struct kvm_vcpu_arch *arch = &vcpu->arch;
2421         enum emulation_result er = EMULATE_DONE;
2422
2423         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2424                 /* save old pc */
2425                 kvm_write_c0_guest_epc(cop0, arch->pc);
2426                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2427
2428                 if (cause & CAUSEF_BD)
2429                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2430                 else
2431                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2432
2433                 kvm_debug("Delivering FPE @ pc %#lx\n", arch->pc);
2434
2435                 kvm_change_c0_guest_cause(cop0, (0xff),
2436                                           (EXCCODE_FPE << CAUSEB_EXCCODE));
2437
2438                 /* Set PC to the exception entry point */
2439                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2440
2441         } else {
2442                 kvm_err("Trying to deliver FPE when EXL is already set\n");
2443                 er = EMULATE_FAIL;
2444         }
2445
2446         return er;
2447 }
2448
2449 enum emulation_result kvm_mips_emulate_msadis_exc(u32 cause,
2450                                                   u32 *opc,
2451                                                   struct kvm_run *run,
2452                                                   struct kvm_vcpu *vcpu)
2453 {
2454         struct mips_coproc *cop0 = vcpu->arch.cop0;
2455         struct kvm_vcpu_arch *arch = &vcpu->arch;
2456         enum emulation_result er = EMULATE_DONE;
2457
2458         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2459                 /* save old pc */
2460                 kvm_write_c0_guest_epc(cop0, arch->pc);
2461                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2462
2463                 if (cause & CAUSEF_BD)
2464                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2465                 else
2466                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2467
2468                 kvm_debug("Delivering MSADIS @ pc %#lx\n", arch->pc);
2469
2470                 kvm_change_c0_guest_cause(cop0, (0xff),
2471                                           (EXCCODE_MSADIS << CAUSEB_EXCCODE));
2472
2473                 /* Set PC to the exception entry point */
2474                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2475
2476         } else {
2477                 kvm_err("Trying to deliver MSADIS when EXL is already set\n");
2478                 er = EMULATE_FAIL;
2479         }
2480
2481         return er;
2482 }
2483
2484 enum emulation_result kvm_mips_handle_ri(u32 cause, u32 *opc,
2485                                          struct kvm_run *run,
2486                                          struct kvm_vcpu *vcpu)
2487 {
2488         struct mips_coproc *cop0 = vcpu->arch.cop0;
2489         struct kvm_vcpu_arch *arch = &vcpu->arch;
2490         enum emulation_result er = EMULATE_DONE;
2491         unsigned long curr_pc;
2492         union mips_instruction inst;
2493         int err;
2494
2495         /*
2496          * Update PC and hold onto current PC in case there is
2497          * an error and we want to rollback the PC
2498          */
2499         curr_pc = vcpu->arch.pc;
2500         er = update_pc(vcpu, cause);
2501         if (er == EMULATE_FAIL)
2502                 return er;
2503
2504         /* Fetch the instruction. */
2505         if (cause & CAUSEF_BD)
2506                 opc += 1;
2507         err = kvm_get_badinstr(opc, vcpu, &inst.word);
2508         if (err) {
2509                 kvm_err("%s: Cannot get inst @ %p (%d)\n", __func__, opc, err);
2510                 return EMULATE_FAIL;
2511         }
2512
2513         if (inst.r_format.opcode == spec3_op &&
2514             inst.r_format.func == rdhwr_op &&
2515             inst.r_format.rs == 0 &&
2516             (inst.r_format.re >> 3) == 0) {
2517                 int usermode = !KVM_GUEST_KERNEL_MODE(vcpu);
2518                 int rd = inst.r_format.rd;
2519                 int rt = inst.r_format.rt;
2520                 int sel = inst.r_format.re & 0x7;
2521
2522                 /* If usermode, check RDHWR rd is allowed by guest HWREna */
2523                 if (usermode && !(kvm_read_c0_guest_hwrena(cop0) & BIT(rd))) {
2524                         kvm_debug("RDHWR %#x disallowed by HWREna @ %p\n",
2525                                   rd, opc);
2526                         goto emulate_ri;
2527                 }
2528                 switch (rd) {
2529                 case MIPS_HWR_CPUNUM:           /* CPU number */
2530                         arch->gprs[rt] = vcpu->vcpu_id;
2531                         break;
2532                 case MIPS_HWR_SYNCISTEP:        /* SYNCI length */
2533                         arch->gprs[rt] = min(current_cpu_data.dcache.linesz,
2534                                              current_cpu_data.icache.linesz);
2535                         break;
2536                 case MIPS_HWR_CC:               /* Read count register */
2537                         arch->gprs[rt] = (s32)kvm_mips_read_count(vcpu);
2538                         break;
2539                 case MIPS_HWR_CCRES:            /* Count register resolution */
2540                         switch (current_cpu_data.cputype) {
2541                         case CPU_20KC:
2542                         case CPU_25KF:
2543                                 arch->gprs[rt] = 1;
2544                                 break;
2545                         default:
2546                                 arch->gprs[rt] = 2;
2547                         }
2548                         break;
2549                 case MIPS_HWR_ULR:              /* Read UserLocal register */
2550                         arch->gprs[rt] = kvm_read_c0_guest_userlocal(cop0);
2551                         break;
2552
2553                 default:
2554                         kvm_debug("RDHWR %#x not supported @ %p\n", rd, opc);
2555                         goto emulate_ri;
2556                 }
2557
2558                 trace_kvm_hwr(vcpu, KVM_TRACE_RDHWR, KVM_TRACE_HWR(rd, sel),
2559                               vcpu->arch.gprs[rt]);
2560         } else {
2561                 kvm_debug("Emulate RI not supported @ %p: %#x\n",
2562                           opc, inst.word);
2563                 goto emulate_ri;
2564         }
2565
2566         return EMULATE_DONE;
2567
2568 emulate_ri:
2569         /*
2570          * Rollback PC (if in branch delay slot then the PC already points to
2571          * branch target), and pass the RI exception to the guest OS.
2572          */
2573         vcpu->arch.pc = curr_pc;
2574         return kvm_mips_emulate_ri_exc(cause, opc, run, vcpu);
2575 }
2576
2577 enum emulation_result kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu,
2578                                                   struct kvm_run *run)
2579 {
2580         unsigned long *gpr = &vcpu->arch.gprs[vcpu->arch.io_gpr];
2581         enum emulation_result er = EMULATE_DONE;
2582
2583         if (run->mmio.len > sizeof(*gpr)) {
2584                 kvm_err("Bad MMIO length: %d", run->mmio.len);
2585                 er = EMULATE_FAIL;
2586                 goto done;
2587         }
2588
2589         /* Restore saved resume PC */
2590         vcpu->arch.pc = vcpu->arch.io_pc;
2591
2592         switch (run->mmio.len) {
2593         case 8:
2594                 *gpr = *(s64 *)run->mmio.data;
2595                 break;
2596
2597         case 4:
2598                 if (vcpu->mmio_needed == 2)
2599                         *gpr = *(s32 *)run->mmio.data;
2600                 else
2601                         *gpr = *(u32 *)run->mmio.data;
2602                 break;
2603
2604         case 2:
2605                 if (vcpu->mmio_needed == 2)
2606                         *gpr = *(s16 *) run->mmio.data;
2607                 else
2608                         *gpr = *(u16 *)run->mmio.data;
2609
2610                 break;
2611         case 1:
2612                 if (vcpu->mmio_needed == 2)
2613                         *gpr = *(s8 *) run->mmio.data;
2614                 else
2615                         *gpr = *(u8 *) run->mmio.data;
2616                 break;
2617         }
2618
2619 done:
2620         return er;
2621 }
2622
2623 static enum emulation_result kvm_mips_emulate_exc(u32 cause,
2624                                                   u32 *opc,
2625                                                   struct kvm_run *run,
2626                                                   struct kvm_vcpu *vcpu)
2627 {
2628         u32 exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
2629         struct mips_coproc *cop0 = vcpu->arch.cop0;
2630         struct kvm_vcpu_arch *arch = &vcpu->arch;
2631         enum emulation_result er = EMULATE_DONE;
2632
2633         if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
2634                 /* save old pc */
2635                 kvm_write_c0_guest_epc(cop0, arch->pc);
2636                 kvm_set_c0_guest_status(cop0, ST0_EXL);
2637
2638                 if (cause & CAUSEF_BD)
2639                         kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
2640                 else
2641                         kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
2642
2643                 kvm_change_c0_guest_cause(cop0, (0xff),
2644                                           (exccode << CAUSEB_EXCCODE));
2645
2646                 /* Set PC to the exception entry point */
2647                 arch->pc = kvm_mips_guest_exception_base(vcpu) + 0x180;
2648                 kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
2649
2650                 kvm_debug("Delivering EXC %d @ pc %#lx, badVaddr: %#lx\n",
2651                           exccode, kvm_read_c0_guest_epc(cop0),
2652                           kvm_read_c0_guest_badvaddr(cop0));
2653         } else {
2654                 kvm_err("Trying to deliver EXC when EXL is already set\n");
2655                 er = EMULATE_FAIL;
2656         }
2657
2658         return er;
2659 }
2660
2661 enum emulation_result kvm_mips_check_privilege(u32 cause,
2662                                                u32 *opc,
2663                                                struct kvm_run *run,
2664                                                struct kvm_vcpu *vcpu)
2665 {
2666         enum emulation_result er = EMULATE_DONE;
2667         u32 exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
2668         unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
2669
2670         int usermode = !KVM_GUEST_KERNEL_MODE(vcpu);
2671
2672         if (usermode) {
2673                 switch (exccode) {
2674                 case EXCCODE_INT:
2675                 case EXCCODE_SYS:
2676                 case EXCCODE_BP:
2677                 case EXCCODE_RI:
2678                 case EXCCODE_TR:
2679                 case EXCCODE_MSAFPE:
2680                 case EXCCODE_FPE:
2681                 case EXCCODE_MSADIS:
2682                         break;
2683
2684                 case EXCCODE_CPU:
2685                         if (((cause & CAUSEF_CE) >> CAUSEB_CE) == 0)
2686                                 er = EMULATE_PRIV_FAIL;
2687                         break;
2688
2689                 case EXCCODE_MOD:
2690                         break;
2691
2692                 case EXCCODE_TLBL:
2693                         /*
2694                          * We we are accessing Guest kernel space, then send an
2695                          * address error exception to the guest
2696                          */
2697                         if (badvaddr >= (unsigned long) KVM_GUEST_KSEG0) {
2698                                 kvm_debug("%s: LD MISS @ %#lx\n", __func__,
2699                                           badvaddr);
2700                                 cause &= ~0xff;
2701                                 cause |= (EXCCODE_ADEL << CAUSEB_EXCCODE);
2702                                 er = EMULATE_PRIV_FAIL;
2703                         }
2704                         break;
2705
2706                 case EXCCODE_TLBS:
2707                         /*
2708                          * We we are accessing Guest kernel space, then send an
2709                          * address error exception to the guest
2710                          */
2711                         if (badvaddr >= (unsigned long) KVM_GUEST_KSEG0) {
2712                                 kvm_debug("%s: ST MISS @ %#lx\n", __func__,
2713                                           badvaddr);
2714                                 cause &= ~0xff;
2715                                 cause |= (EXCCODE_ADES << CAUSEB_EXCCODE);
2716                                 er = EMULATE_PRIV_FAIL;
2717                         }
2718                         break;
2719
2720                 case EXCCODE_ADES:
2721                         kvm_debug("%s: address error ST @ %#lx\n", __func__,
2722                                   badvaddr);
2723                         if ((badvaddr & PAGE_MASK) == KVM_GUEST_COMMPAGE_ADDR) {
2724                                 cause &= ~0xff;
2725                                 cause |= (EXCCODE_TLBS << CAUSEB_EXCCODE);
2726                         }
2727                         er = EMULATE_PRIV_FAIL;
2728                         break;
2729                 case EXCCODE_ADEL:
2730                         kvm_debug("%s: address error LD @ %#lx\n", __func__,
2731                                   badvaddr);
2732                         if ((badvaddr & PAGE_MASK) == KVM_GUEST_COMMPAGE_ADDR) {
2733                                 cause &= ~0xff;
2734                                 cause |= (EXCCODE_TLBL << CAUSEB_EXCCODE);
2735                         }
2736                         er = EMULATE_PRIV_FAIL;
2737                         break;
2738                 default:
2739                         er = EMULATE_PRIV_FAIL;
2740                         break;
2741                 }
2742         }
2743
2744         if (er == EMULATE_PRIV_FAIL)
2745                 kvm_mips_emulate_exc(cause, opc, run, vcpu);
2746
2747         return er;
2748 }
2749
2750 /*
2751  * User Address (UA) fault, this could happen if
2752  * (1) TLB entry not present/valid in both Guest and shadow host TLBs, in this
2753  *     case we pass on the fault to the guest kernel and let it handle it.
2754  * (2) TLB entry is present in the Guest TLB but not in the shadow, in this
2755  *     case we inject the TLB from the Guest TLB into the shadow host TLB
2756  */
2757 enum emulation_result kvm_mips_handle_tlbmiss(u32 cause,
2758                                               u32 *opc,
2759                                               struct kvm_run *run,
2760                                               struct kvm_vcpu *vcpu,
2761                                               bool write_fault)
2762 {
2763         enum emulation_result er = EMULATE_DONE;
2764         u32 exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
2765         unsigned long va = vcpu->arch.host_cp0_badvaddr;
2766         int index;
2767
2768         kvm_debug("kvm_mips_handle_tlbmiss: badvaddr: %#lx\n",
2769                   vcpu->arch.host_cp0_badvaddr);
2770
2771         /*
2772          * KVM would not have got the exception if this entry was valid in the
2773          * shadow host TLB. Check the Guest TLB, if the entry is not there then
2774          * send the guest an exception. The guest exc handler should then inject
2775          * an entry into the guest TLB.
2776          */
2777         index = kvm_mips_guest_tlb_lookup(vcpu,
2778                       (va & VPN2_MASK) |
2779                       (kvm_read_c0_guest_entryhi(vcpu->arch.cop0) &
2780                        KVM_ENTRYHI_ASID));
2781         if (index < 0) {
2782                 if (exccode == EXCCODE_TLBL) {
2783                         er = kvm_mips_emulate_tlbmiss_ld(cause, opc, run, vcpu);
2784                 } else if (exccode == EXCCODE_TLBS) {
2785                         er = kvm_mips_emulate_tlbmiss_st(cause, opc, run, vcpu);
2786                 } else {
2787                         kvm_err("%s: invalid exc code: %d\n", __func__,
2788                                 exccode);
2789                         er = EMULATE_FAIL;
2790                 }
2791         } else {
2792                 struct kvm_mips_tlb *tlb = &vcpu->arch.guest_tlb[index];
2793
2794                 /*
2795                  * Check if the entry is valid, if not then setup a TLB invalid
2796                  * exception to the guest
2797                  */
2798                 if (!TLB_IS_VALID(*tlb, va)) {
2799                         if (exccode == EXCCODE_TLBL) {
2800                                 er = kvm_mips_emulate_tlbinv_ld(cause, opc, run,
2801                                                                 vcpu);
2802                         } else if (exccode == EXCCODE_TLBS) {
2803                                 er = kvm_mips_emulate_tlbinv_st(cause, opc, run,
2804                                                                 vcpu);
2805                         } else {
2806                                 kvm_err("%s: invalid exc code: %d\n", __func__,
2807                                         exccode);
2808                                 er = EMULATE_FAIL;
2809                         }
2810                 } else {
2811                         kvm_debug("Injecting hi: %#lx, lo0: %#lx, lo1: %#lx into shadow host TLB\n",
2812                                   tlb->tlb_hi, tlb->tlb_lo[0], tlb->tlb_lo[1]);
2813                         /*
2814                          * OK we have a Guest TLB entry, now inject it into the
2815                          * shadow host TLB
2816                          */
2817                         if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb, va,
2818                                                                  write_fault)) {
2819                                 kvm_err("%s: handling mapped seg tlb fault for %lx, index: %u, vcpu: %p, ASID: %#lx\n",
2820                                         __func__, va, index, vcpu,
2821                                         read_c0_entryhi());
2822                                 er = EMULATE_FAIL;
2823                         }
2824                 }
2825         }
2826
2827         return er;
2828 }