arch/s390/kvm/diag.c

   1 /*
   2  * handling diagnose instructions
   3  *
   4  * Copyright IBM Corp. 2008, 2011
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License (version 2 only)
   8  * as published by the Free Software Foundation.
   9  *
  10  *    Author(s): Carsten Otte <cotte@de.ibm.com>
  11  *               Christian Borntraeger <borntraeger@de.ibm.com>
  12  */
  13
  14 #include <linux/kvm.h>
  15 #include <linux/kvm_host.h>
  16 #include <asm/pgalloc.h>
  17 #include <asm/virtio-ccw.h>
  18 #include "kvm-s390.h"
  19 #include "trace.h"
  20 #include "trace-s390.h"
  21 #include "gaccess.h"
  22
  23 static int diag_release_pages(struct kvm_vcpu *vcpu)
  24 {
  25         unsigned long start, end;
  26         unsigned long prefix  = vcpu->arch.sie_block->prefix;
  27
  28         start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
  29         end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;
  30
  31         if (start & ~PAGE_MASK || end & ~PAGE_MASK || start > end
  32             || start < 2 * PAGE_SIZE)
  33                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  34
  35         VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
  36         vcpu->stat.diagnose_10++;
  37
  38         /* we checked for start > end above */
  39         if (end < prefix || start >= prefix + 2 * PAGE_SIZE) {
  40                 gmap_discard(start, end, vcpu->arch.gmap);
  41         } else {
  42                 if (start < prefix)
  43                         gmap_discard(start, prefix, vcpu->arch.gmap);
  44                 if (end >= prefix)
  45                         gmap_discard(prefix + 2 * PAGE_SIZE,
  46                                      end, vcpu->arch.gmap);
  47         }
  48         return 0;
  49 }
  50
  51 static int __diag_page_ref_service(struct kvm_vcpu *vcpu)
  52 {
  53         struct prs_parm {
  54                 u16 code;
  55                 u16 subcode;
  56                 u16 parm_len;
  57                 u16 parm_version;
  58                 u64 token_addr;
  59                 u64 select_mask;
  60                 u64 compare_mask;
  61                 u64 zarch;
  62         };
  63         struct prs_parm parm;
  64         int rc;
  65         u16 rx = (vcpu->arch.sie_block->ipa & 0xf0) >> 4;
  66         u16 ry = (vcpu->arch.sie_block->ipa & 0x0f);
  67         unsigned long hva_token = KVM_HVA_ERR_BAD;
  68
  69         if (vcpu->run->s.regs.gprs[rx] & 7)
  70                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  71         if (copy_from_guest(vcpu, &parm, vcpu->run->s.regs.gprs[rx], sizeof(parm)))
  72                 return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
  73         if (parm.parm_version != 2 || parm.parm_len < 5 || parm.code != 0x258)
  74                 return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  75
  76         switch (parm.subcode) {
  77         case 0: /* TOKEN */
  78                 if (vcpu->arch.pfault_token != KVM_S390_PFAULT_TOKEN_INVALID) {
  79                         /*
  80                          * If the pagefault handshake is already activated,
  81                          * the token must not be changed.  We have to return
  82                          * decimal 8 instead, as mandated in SC24-6084.
  83                          */
  84                         vcpu->run->s.regs.gprs[ry] = 8;
  85                         return 0;
  86                 }
  87
  88                 if ((parm.compare_mask & parm.select_mask) != parm.compare_mask ||
  89                     parm.token_addr & 7 || parm.zarch != 0x8000000000000000ULL)
  90                         return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
  91
  92                 hva_token = gfn_to_hva(vcpu->kvm, gpa_to_gfn(parm.token_addr));
  93                 if (kvm_is_error_hva(hva_token))
  94                         return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
  95
  96                 vcpu->arch.pfault_token = parm.token_addr;
  97                 vcpu->arch.pfault_select = parm.select_mask;
  98                 vcpu->arch.pfault_compare = parm.compare_mask;
  99                 vcpu->run->s.regs.gprs[ry] = 0;
 100                 rc = 0;
 101                 break;
 102         case 1: /*
 103                  * CANCEL
 104                  * Specification allows to let already pending tokens survive
 105                  * the cancel, therefore to reduce code complexity, we assume
 106                  * all outstanding tokens are already pending.
 107                  */
 108                 if (parm.token_addr || parm.select_mask ||
 109                     parm.compare_mask || parm.zarch)
 110                         return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 111
 112                 vcpu->run->s.regs.gprs[ry] = 0;
 113                 /*
 114                  * If the pfault handling was not established or is already
 115                  * canceled SC24-6084 requests to return decimal 4.
 116                  */
 117                 if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID)
 118                         vcpu->run->s.regs.gprs[ry] = 4;
 119                 else
 120                         vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
 121
 122                 rc = 0;
 123                 break;
 124         default:
 125                 rc = -EOPNOTSUPP;
 126                 break;
 127         }
 128
 129         return rc;
 130 }
 131
 132 static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
 133 {
 134         VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
 135         vcpu->stat.diagnose_44++;
 136         kvm_vcpu_on_spin(vcpu);
 137         return 0;
 138 }
 139
 140 static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
 141 {
 142         struct kvm *kvm = vcpu->kvm;
 143         struct kvm_vcpu *tcpu;
 144         int tid;
 145         int i;
 146
 147         tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
 148         vcpu->stat.diagnose_9c++;
 149         VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);
 150
 151         if (tid == vcpu->vcpu_id)
 152                 return 0;
 153
 154         kvm_for_each_vcpu(i, tcpu, kvm)
 155                 if (tcpu->vcpu_id == tid) {
 156                         kvm_vcpu_yield_to(tcpu);
 157                         break;
 158                 }
 159
 160         return 0;
 161 }
 162
 163 static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
 164 {
 165         unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;
 166         unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff;
 167
 168         VCPU_EVENT(vcpu, 5, "diag ipl functions, subcode %lx", subcode);
 169         switch (subcode) {
 170         case 3:
 171                 vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
 172                 page_table_reset_pgste(current->mm, 0, TASK_SIZE);
 173                 break;
 174         case 4:
 175                 vcpu->run->s390_reset_flags = 0;
 176                 page_table_reset_pgste(current->mm, 0, TASK_SIZE);
 177                 break;
 178         default:
 179                 return -EOPNOTSUPP;
 180         }
 181
 182         atomic_set_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
 183         vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;
 184         vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;
 185         vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;
 186         vcpu->run->exit_reason = KVM_EXIT_S390_RESET;
 187         VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx",
 188           vcpu->run->s390_reset_flags);
 189         trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags);
 190         return -EREMOTE;
 191 }
 192
 193 static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
 194 {
 195         int ret;
 196
 197         /* No virtio-ccw notification? Get out quickly. */
 198         if (!vcpu->kvm->arch.css_support ||
 199             (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
 200                 return -EOPNOTSUPP;
 201
 202         /*
 203          * The layout is as follows:
 204          * - gpr 2 contains the subchannel id (passed as addr)
 205          * - gpr 3 contains the virtqueue index (passed as datamatch)
 206          * - gpr 4 contains the index on the bus (optionally)
 207          */
 208         ret = kvm_io_bus_write_cookie(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
 209                                       vcpu->run->s.regs.gprs[2] & 0xffffffff,
 210                                       8, &vcpu->run->s.regs.gprs[3],
 211                                       vcpu->run->s.regs.gprs[4]);
 212
 213         /*
 214          * Return cookie in gpr 2, but don't overwrite the register if the
 215          * diagnose will be handled by userspace.
 216          */
 217         if (ret != -EOPNOTSUPP)
 218                 vcpu->run->s.regs.gprs[2] = ret;
 219         /* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */
 220         return ret < 0 ? ret : 0;
 221 }
 222
 223 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
 224 {
 225         int code = kvm_s390_get_base_disp_rs(vcpu) & 0xffff;
 226
 227         if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 228                 return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
 229
 230         trace_kvm_s390_handle_diag(vcpu, code);
 231         switch (code) {
 232         case 0x10:
 233                 return diag_release_pages(vcpu);
 234         case 0x44:
 235                 return __diag_time_slice_end(vcpu);
 236         case 0x9c:
 237                 return __diag_time_slice_end_directed(vcpu);
 238         case 0x258:
 239                 return __diag_page_ref_service(vcpu);
 240         case 0x308:
 241                 return __diag_ipl_functions(vcpu);
 242         case 0x500:
 243                 return __diag_virtio_hypercall(vcpu);
 244         default:
 245                 return -EOPNOTSUPP;
 246         }
 247 }