arch/arm64/kvm/hypercalls.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2019 Arm Ltd.
   3
   4 #include <linux/arm-smccc.h>
   5 #include <linux/kvm_host.h>
   6
   7 #include <asm/kvm_emulate.h>
   8
   9 #include <kvm/arm_hypercalls.h>
  10 #include <kvm/arm_psci.h>
  11
  12 #define KVM_ARM_SMCCC_STD_FEATURES                              \
  13         GENMASK(KVM_REG_ARM_STD_BMAP_BIT_COUNT - 1, 0)
  14 #define KVM_ARM_SMCCC_STD_HYP_FEATURES                          \
  15         GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_COUNT - 1, 0)
  16 #define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES                       \
  17         GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT - 1, 0)
  18
  19 static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
  20 {
  21         struct system_time_snapshot systime_snapshot;
  22         u64 cycles = ~0UL;
  23         u32 feature;
  24
  25         /*
  26          * system time and counter value must captured at the same
  27          * time to keep consistency and precision.
  28          */
  29         ktime_get_snapshot(&systime_snapshot);
  30
  31         /*
  32          * This is only valid if the current clocksource is the
  33          * architected counter, as this is the only one the guest
  34          * can see.
  35          */
  36         if (systime_snapshot.cs_id != CSID_ARM_ARCH_COUNTER)
  37                 return;
  38
  39         /*
  40          * The guest selects one of the two reference counters
  41          * (virtual or physical) with the first argument of the SMCCC
  42          * call. In case the identifier is not supported, error out.
  43          */
  44         feature = smccc_get_arg1(vcpu);
  45         switch (feature) {
  46         case KVM_PTP_VIRT_COUNTER:
  47                 cycles = systime_snapshot.cycles - vcpu->kvm->arch.timer_data.voffset;
  48                 break;
  49         case KVM_PTP_PHYS_COUNTER:
  50                 cycles = systime_snapshot.cycles - vcpu->kvm->arch.timer_data.poffset;
  51                 break;
  52         default:
  53                 return;
  54         }
  55
  56         /*
  57          * This relies on the top bit of val[0] never being set for
  58          * valid values of system time, because that is *really* far
  59          * in the future (about 292 years from 1970, and at that stage
  60          * nobody will give a damn about it).
  61          */
  62         val[0] = upper_32_bits(systime_snapshot.real);
  63         val[1] = lower_32_bits(systime_snapshot.real);
  64         val[2] = upper_32_bits(cycles);
  65         val[3] = lower_32_bits(cycles);
  66 }
  67
  68 static bool kvm_smccc_default_allowed(u32 func_id)
  69 {
  70         switch (func_id) {
  71         /*
  72          * List of function-ids that are not gated with the bitmapped
  73          * feature firmware registers, and are to be allowed for
  74          * servicing the call by default.
  75          */
  76         case ARM_SMCCC_VERSION_FUNC_ID:
  77         case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
  78                 return true;
  79         default:
  80                 /* PSCI 0.2 and up is in the 0:0x1f range */
  81                 if (ARM_SMCCC_OWNER_NUM(func_id) == ARM_SMCCC_OWNER_STANDARD &&
  82                     ARM_SMCCC_FUNC_NUM(func_id) <= 0x1f)
  83                         return true;
  84
  85                 /*
  86                  * KVM's PSCI 0.1 doesn't comply with SMCCC, and has
  87                  * its own function-id base and range
  88                  */
  89                 if (func_id >= KVM_PSCI_FN(0) && func_id <= KVM_PSCI_FN(3))
  90                         return true;
  91
  92                 return false;
  93         }
  94 }
  95
  96 static bool kvm_smccc_test_fw_bmap(struct kvm_vcpu *vcpu, u32 func_id)
  97 {
  98         struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
  99
 100         switch (func_id) {
 101         case ARM_SMCCC_TRNG_VERSION:
 102         case ARM_SMCCC_TRNG_FEATURES:
 103         case ARM_SMCCC_TRNG_GET_UUID:
 104         case ARM_SMCCC_TRNG_RND32:
 105         case ARM_SMCCC_TRNG_RND64:
 106                 return test_bit(KVM_REG_ARM_STD_BIT_TRNG_V1_0,
 107                                 &smccc_feat->std_bmap);
 108         case ARM_SMCCC_HV_PV_TIME_FEATURES:
 109         case ARM_SMCCC_HV_PV_TIME_ST:
 110                 return test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
 111                                 &smccc_feat->std_hyp_bmap);
 112         case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
 113         case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
 114                 return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT,
 115                                 &smccc_feat->vendor_hyp_bmap);
 116         case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
 117                 return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_PTP,
 118                                 &smccc_feat->vendor_hyp_bmap);
 119         default:
 120                 return false;
 121         }
 122 }
 123
 124 #define SMC32_ARCH_RANGE_BEGIN  ARM_SMCCC_VERSION_FUNC_ID
 125 #define SMC32_ARCH_RANGE_END    ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,         \
 126                                                    ARM_SMCCC_SMC_32,            \
 127                                                    0, ARM_SMCCC_FUNC_MASK)
 128
 129 #define SMC64_ARCH_RANGE_BEGIN  ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,         \
 130                                                    ARM_SMCCC_SMC_64,            \
 131                                                    0, 0)
 132 #define SMC64_ARCH_RANGE_END    ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,         \
 133                                                    ARM_SMCCC_SMC_64,            \
 134                                                    0, ARM_SMCCC_FUNC_MASK)
 135
 136 static void init_smccc_filter(struct kvm *kvm)
 137 {
 138         int r;
 139
 140         mt_init(&kvm->arch.smccc_filter);
 141
 142         /*
 143          * Prevent userspace from handling any SMCCC calls in the architecture
 144          * range, avoiding the risk of misrepresenting Spectre mitigation status
 145          * to the guest.
 146          */
 147         r = mtree_insert_range(&kvm->arch.smccc_filter,
 148                                SMC32_ARCH_RANGE_BEGIN, SMC32_ARCH_RANGE_END,
 149                                xa_mk_value(KVM_SMCCC_FILTER_HANDLE),
 150                                GFP_KERNEL_ACCOUNT);
 151         WARN_ON_ONCE(r);
 152
 153         r = mtree_insert_range(&kvm->arch.smccc_filter,
 154                                SMC64_ARCH_RANGE_BEGIN, SMC64_ARCH_RANGE_END,
 155                                xa_mk_value(KVM_SMCCC_FILTER_HANDLE),
 156                                GFP_KERNEL_ACCOUNT);
 157         WARN_ON_ONCE(r);
 158
 159 }
 160
 161 static int kvm_smccc_set_filter(struct kvm *kvm, struct kvm_smccc_filter __user *uaddr)
 162 {
 163         const void *zero_page = page_to_virt(ZERO_PAGE(0));
 164         struct kvm_smccc_filter filter;
 165         u32 start, end;
 166         int r;
 167
 168         if (copy_from_user(&filter, uaddr, sizeof(filter)))
 169                 return -EFAULT;
 170
 171         if (memcmp(filter.pad, zero_page, sizeof(filter.pad)))
 172                 return -EINVAL;
 173
 174         start = filter.base;
 175         end = start + filter.nr_functions - 1;
 176
 177         if (end < start || filter.action >= NR_SMCCC_FILTER_ACTIONS)
 178                 return -EINVAL;
 179
 180         mutex_lock(&kvm->arch.config_lock);
 181
 182         if (kvm_vm_has_ran_once(kvm)) {
 183                 r = -EBUSY;
 184                 goto out_unlock;
 185         }
 186
 187         r = mtree_insert_range(&kvm->arch.smccc_filter, start, end,
 188                                xa_mk_value(filter.action), GFP_KERNEL_ACCOUNT);
 189         if (r)
 190                 goto out_unlock;
 191
 192         set_bit(KVM_ARCH_FLAG_SMCCC_FILTER_CONFIGURED, &kvm->arch.flags);
 193
 194 out_unlock:
 195         mutex_unlock(&kvm->arch.config_lock);
 196         return r;
 197 }
 198
 199 static u8 kvm_smccc_filter_get_action(struct kvm *kvm, u32 func_id)
 200 {
 201         unsigned long idx = func_id;
 202         void *val;
 203
 204         if (!test_bit(KVM_ARCH_FLAG_SMCCC_FILTER_CONFIGURED, &kvm->arch.flags))
 205                 return KVM_SMCCC_FILTER_HANDLE;
 206
 207         /*
 208          * But where's the error handling, you say?
 209          *
 210          * mt_find() returns NULL if no entry was found, which just so happens
 211          * to match KVM_SMCCC_FILTER_HANDLE.
 212          */
 213         val = mt_find(&kvm->arch.smccc_filter, &idx, idx);
 214         return xa_to_value(val);
 215 }
 216
 217 static u8 kvm_smccc_get_action(struct kvm_vcpu *vcpu, u32 func_id)
 218 {
 219         /*
 220          * Intervening actions in the SMCCC filter take precedence over the
 221          * pseudo-firmware register bitmaps.
 222          */
 223         u8 action = kvm_smccc_filter_get_action(vcpu->kvm, func_id);
 224         if (action != KVM_SMCCC_FILTER_HANDLE)
 225                 return action;
 226
 227         if (kvm_smccc_test_fw_bmap(vcpu, func_id) ||
 228             kvm_smccc_default_allowed(func_id))
 229                 return KVM_SMCCC_FILTER_HANDLE;
 230
 231         return KVM_SMCCC_FILTER_DENY;
 232 }
 233
 234 static void kvm_prepare_hypercall_exit(struct kvm_vcpu *vcpu, u32 func_id)
 235 {
 236         u8 ec = ESR_ELx_EC(kvm_vcpu_get_esr(vcpu));
 237         struct kvm_run *run = vcpu->run;
 238         u64 flags = 0;
 239
 240         if (ec == ESR_ELx_EC_SMC32 || ec == ESR_ELx_EC_SMC64)
 241                 flags |= KVM_HYPERCALL_EXIT_SMC;
 242
 243         if (!kvm_vcpu_trap_il_is32bit(vcpu))
 244                 flags |= KVM_HYPERCALL_EXIT_16BIT;
 245
 246         run->exit_reason = KVM_EXIT_HYPERCALL;
 247         run->hypercall = (typeof(run->hypercall)) {
 248                 .nr     = func_id,
 249                 .flags  = flags,
 250         };
 251 }
 252
 253 int kvm_smccc_call_handler(struct kvm_vcpu *vcpu)
 254 {
 255         struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
 256         u32 func_id = smccc_get_function(vcpu);
 257         u64 val[4] = {SMCCC_RET_NOT_SUPPORTED};
 258         u32 feature;
 259         u8 action;
 260         gpa_t gpa;
 261
 262         action = kvm_smccc_get_action(vcpu, func_id);
 263         switch (action) {
 264         case KVM_SMCCC_FILTER_HANDLE:
 265                 break;
 266         case KVM_SMCCC_FILTER_DENY:
 267                 goto out;
 268         case KVM_SMCCC_FILTER_FWD_TO_USER:
 269                 kvm_prepare_hypercall_exit(vcpu, func_id);
 270                 return 0;
 271         default:
 272                 WARN_RATELIMIT(1, "Unhandled SMCCC filter action: %d\n", action);
 273                 goto out;
 274         }
 275
 276         switch (func_id) {
 277         case ARM_SMCCC_VERSION_FUNC_ID:
 278                 val[0] = ARM_SMCCC_VERSION_1_1;
 279                 break;
 280         case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
 281                 feature = smccc_get_arg1(vcpu);
 282                 switch (feature) {
 283                 case ARM_SMCCC_ARCH_WORKAROUND_1:
 284                         switch (arm64_get_spectre_v2_state()) {
 285                         case SPECTRE_VULNERABLE:
 286                                 break;
 287                         case SPECTRE_MITIGATED:
 288                                 val[0] = SMCCC_RET_SUCCESS;
 289                                 break;
 290                         case SPECTRE_UNAFFECTED:
 291                                 val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
 292                                 break;
 293                         }
 294                         break;
 295                 case ARM_SMCCC_ARCH_WORKAROUND_2:
 296                         switch (arm64_get_spectre_v4_state()) {
 297                         case SPECTRE_VULNERABLE:
 298                                 break;
 299                         case SPECTRE_MITIGATED:
 300                                 /*
 301                                  * SSBS everywhere: Indicate no firmware
 302                                  * support, as the SSBS support will be
 303                                  * indicated to the guest and the default is
 304                                  * safe.
 305                                  *
 306                                  * Otherwise, expose a permanent mitigation
 307                                  * to the guest, and hide SSBS so that the
 308                                  * guest stays protected.
 309                                  */
 310                                 if (cpus_have_final_cap(ARM64_SSBS))
 311                                         break;
 312                                 fallthrough;
 313                         case SPECTRE_UNAFFECTED:
 314                                 val[0] = SMCCC_RET_NOT_REQUIRED;
 315                                 break;
 316                         }
 317                         break;
 318                 case ARM_SMCCC_ARCH_WORKAROUND_3:
 319                         switch (arm64_get_spectre_bhb_state()) {
 320                         case SPECTRE_VULNERABLE:
 321                                 break;
 322                         case SPECTRE_MITIGATED:
 323                                 val[0] = SMCCC_RET_SUCCESS;
 324                                 break;
 325                         case SPECTRE_UNAFFECTED:
 326                                 val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
 327                                 break;
 328                         }
 329                         break;
 330                 case ARM_SMCCC_HV_PV_TIME_FEATURES:
 331                         if (test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
 332                                      &smccc_feat->std_hyp_bmap))
 333                                 val[0] = SMCCC_RET_SUCCESS;
 334                         break;
 335                 }
 336                 break;
 337         case ARM_SMCCC_HV_PV_TIME_FEATURES:
 338                 val[0] = kvm_hypercall_pv_features(vcpu);
 339                 break;
 340         case ARM_SMCCC_HV_PV_TIME_ST:
 341                 gpa = kvm_init_stolen_time(vcpu);
 342                 if (gpa != INVALID_GPA)
 343                         val[0] = gpa;
 344                 break;
 345         case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
 346                 val[0] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0;
 347                 val[1] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1;
 348                 val[2] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2;
 349                 val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3;
 350                 break;
 351         case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
 352                 val[0] = smccc_feat->vendor_hyp_bmap;
 353                 break;
 354         case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
 355                 kvm_ptp_get_time(vcpu, val);
 356                 break;
 357         case ARM_SMCCC_TRNG_VERSION:
 358         case ARM_SMCCC_TRNG_FEATURES:
 359         case ARM_SMCCC_TRNG_GET_UUID:
 360         case ARM_SMCCC_TRNG_RND32:
 361         case ARM_SMCCC_TRNG_RND64:
 362                 return kvm_trng_call(vcpu);
 363         default:
 364                 return kvm_psci_call(vcpu);
 365         }
 366
 367 out:
 368         smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]);
 369         return 1;
 370 }
 371
 372 static const u64 kvm_arm_fw_reg_ids[] = {
 373         KVM_REG_ARM_PSCI_VERSION,
 374         KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1,
 375         KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2,
 376         KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3,
 377         KVM_REG_ARM_STD_BMAP,
 378         KVM_REG_ARM_STD_HYP_BMAP,
 379         KVM_REG_ARM_VENDOR_HYP_BMAP,
 380 };
 381
 382 void kvm_arm_init_hypercalls(struct kvm *kvm)
 383 {
 384         struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat;
 385
 386         smccc_feat->std_bmap = KVM_ARM_SMCCC_STD_FEATURES;
 387         smccc_feat->std_hyp_bmap = KVM_ARM_SMCCC_STD_HYP_FEATURES;
 388         smccc_feat->vendor_hyp_bmap = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
 389
 390         init_smccc_filter(kvm);
 391 }
 392
 393 void kvm_arm_teardown_hypercalls(struct kvm *kvm)
 394 {
 395         mtree_destroy(&kvm->arch.smccc_filter);
 396 }
 397
 398 int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
 399 {
 400         return ARRAY_SIZE(kvm_arm_fw_reg_ids);
 401 }
 402
 403 int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
 404 {
 405         int i;
 406
 407         for (i = 0; i < ARRAY_SIZE(kvm_arm_fw_reg_ids); i++) {
 408                 if (put_user(kvm_arm_fw_reg_ids[i], uindices++))
 409                         return -EFAULT;
 410         }
 411
 412         return 0;
 413 }
 414
 415 #define KVM_REG_FEATURE_LEVEL_MASK      GENMASK(3, 0)
 416
 417 /*
 418  * Convert the workaround level into an easy-to-compare number, where higher
 419  * values mean better protection.
 420  */
 421 static int get_kernel_wa_level(u64 regid)
 422 {
 423         switch (regid) {
 424         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
 425                 switch (arm64_get_spectre_v2_state()) {
 426                 case SPECTRE_VULNERABLE:
 427                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
 428                 case SPECTRE_MITIGATED:
 429                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL;
 430                 case SPECTRE_UNAFFECTED:
 431                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED;
 432                 }
 433                 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
 434         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
 435                 switch (arm64_get_spectre_v4_state()) {
 436                 case SPECTRE_MITIGATED:
 437                         /*
 438                          * As for the hypercall discovery, we pretend we
 439                          * don't have any FW mitigation if SSBS is there at
 440                          * all times.
 441                          */
 442                         if (cpus_have_final_cap(ARM64_SSBS))
 443                                 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
 444                         fallthrough;
 445                 case SPECTRE_UNAFFECTED:
 446                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
 447                 case SPECTRE_VULNERABLE:
 448                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
 449                 }
 450                 break;
 451         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
 452                 switch (arm64_get_spectre_bhb_state()) {
 453                 case SPECTRE_VULNERABLE:
 454                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
 455                 case SPECTRE_MITIGATED:
 456                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL;
 457                 case SPECTRE_UNAFFECTED:
 458                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED;
 459                 }
 460                 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
 461         }
 462
 463         return -EINVAL;
 464 }
 465
 466 int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 467 {
 468         struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
 469         void __user *uaddr = (void __user *)(long)reg->addr;
 470         u64 val;
 471
 472         switch (reg->id) {
 473         case KVM_REG_ARM_PSCI_VERSION:
 474                 val = kvm_psci_version(vcpu);
 475                 break;
 476         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
 477         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
 478         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
 479                 val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
 480                 break;
 481         case KVM_REG_ARM_STD_BMAP:
 482                 val = READ_ONCE(smccc_feat->std_bmap);
 483                 break;
 484         case KVM_REG_ARM_STD_HYP_BMAP:
 485                 val = READ_ONCE(smccc_feat->std_hyp_bmap);
 486                 break;
 487         case KVM_REG_ARM_VENDOR_HYP_BMAP:
 488                 val = READ_ONCE(smccc_feat->vendor_hyp_bmap);
 489                 break;
 490         default:
 491                 return -ENOENT;
 492         }
 493
 494         if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
 495                 return -EFAULT;
 496
 497         return 0;
 498 }
 499
 500 static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val)
 501 {
 502         int ret = 0;
 503         struct kvm *kvm = vcpu->kvm;
 504         struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat;
 505         unsigned long *fw_reg_bmap, fw_reg_features;
 506
 507         switch (reg_id) {
 508         case KVM_REG_ARM_STD_BMAP:
 509                 fw_reg_bmap = &smccc_feat->std_bmap;
 510                 fw_reg_features = KVM_ARM_SMCCC_STD_FEATURES;
 511                 break;
 512         case KVM_REG_ARM_STD_HYP_BMAP:
 513                 fw_reg_bmap = &smccc_feat->std_hyp_bmap;
 514                 fw_reg_features = KVM_ARM_SMCCC_STD_HYP_FEATURES;
 515                 break;
 516         case KVM_REG_ARM_VENDOR_HYP_BMAP:
 517                 fw_reg_bmap = &smccc_feat->vendor_hyp_bmap;
 518                 fw_reg_features = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
 519                 break;
 520         default:
 521                 return -ENOENT;
 522         }
 523
 524         /* Check for unsupported bit */
 525         if (val & ~fw_reg_features)
 526                 return -EINVAL;
 527
 528         mutex_lock(&kvm->arch.config_lock);
 529
 530         if (kvm_vm_has_ran_once(kvm) && val != *fw_reg_bmap) {
 531                 ret = -EBUSY;
 532                 goto out;
 533         }
 534
 535         WRITE_ONCE(*fw_reg_bmap, val);
 536 out:
 537         mutex_unlock(&kvm->arch.config_lock);
 538         return ret;
 539 }
 540
 541 int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 542 {
 543         void __user *uaddr = (void __user *)(long)reg->addr;
 544         u64 val;
 545         int wa_level;
 546
 547         if (KVM_REG_SIZE(reg->id) != sizeof(val))
 548                 return -ENOENT;
 549         if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
 550                 return -EFAULT;
 551
 552         switch (reg->id) {
 553         case KVM_REG_ARM_PSCI_VERSION:
 554         {
 555                 bool wants_02;
 556
 557                 wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features);
 558
 559                 switch (val) {
 560                 case KVM_ARM_PSCI_0_1:
 561                         if (wants_02)
 562                                 return -EINVAL;
 563                         vcpu->kvm->arch.psci_version = val;
 564                         return 0;
 565                 case KVM_ARM_PSCI_0_2:
 566                 case KVM_ARM_PSCI_1_0:
 567                 case KVM_ARM_PSCI_1_1:
 568                         if (!wants_02)
 569                                 return -EINVAL;
 570                         vcpu->kvm->arch.psci_version = val;
 571                         return 0;
 572                 }
 573                 break;
 574         }
 575
 576         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
 577         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
 578                 if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
 579                         return -EINVAL;
 580
 581                 if (get_kernel_wa_level(reg->id) < val)
 582                         return -EINVAL;
 583
 584                 return 0;
 585
 586         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
 587                 if (val & ~(KVM_REG_FEATURE_LEVEL_MASK |
 588                             KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED))
 589                         return -EINVAL;
 590
 591                 /* The enabled bit must not be set unless the level is AVAIL. */
 592                 if ((val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED) &&
 593                     (val & KVM_REG_FEATURE_LEVEL_MASK) != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL)
 594                         return -EINVAL;
 595
 596                 /*
 597                  * Map all the possible incoming states to the only two we
 598                  * really want to deal with.
 599                  */
 600                 switch (val & KVM_REG_FEATURE_LEVEL_MASK) {
 601                 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL:
 602                 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN:
 603                         wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
 604                         break;
 605                 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
 606                 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
 607                         wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
 608                         break;
 609                 default:
 610                         return -EINVAL;
 611                 }
 612
 613                 /*
 614                  * We can deal with NOT_AVAIL on NOT_REQUIRED, but not the
 615                  * other way around.
 616                  */
 617                 if (get_kernel_wa_level(reg->id) < wa_level)
 618                         return -EINVAL;
 619
 620                 return 0;
 621         case KVM_REG_ARM_STD_BMAP:
 622         case KVM_REG_ARM_STD_HYP_BMAP:
 623         case KVM_REG_ARM_VENDOR_HYP_BMAP:
 624                 return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val);
 625         default:
 626                 return -ENOENT;
 627         }
 628
 629         return -EINVAL;
 630 }
 631
 632 int kvm_vm_smccc_has_attr(struct kvm *kvm, struct kvm_device_attr *attr)
 633 {
 634         switch (attr->attr) {
 635         case KVM_ARM_VM_SMCCC_FILTER:
 636                 return 0;
 637         default:
 638                 return -ENXIO;
 639         }
 640 }
 641
 642 int kvm_vm_smccc_set_attr(struct kvm *kvm, struct kvm_device_attr *attr)
 643 {
 644         void __user *uaddr = (void __user *)attr->addr;
 645
 646         switch (attr->attr) {
 647         case KVM_ARM_VM_SMCCC_FILTER:
 648                 return kvm_smccc_set_filter(kvm, uaddr);
 649         default:
 650                 return -ENXIO;
 651         }
 652 }