arch/riscv/kvm/vcpu_sbi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2019 Western Digital Corporation or its affiliates.
   4  *
   5  * Authors:
   6  *     Atish Patra <[email protected]>
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/err.h>
  11 #include <linux/kvm_host.h>
  12 #include <asm/sbi.h>
  13 #include <asm/kvm_vcpu_sbi.h>
  14
  15 #ifndef CONFIG_RISCV_SBI_V01
  16 static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
  17         .extid_start = -1UL,
  18         .extid_end = -1UL,
  19         .handler = NULL,
  20 };
  21 #endif
  22
  23 #ifndef CONFIG_RISCV_PMU_SBI
  24 static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_pmu = {
  25         .extid_start = -1UL,
  26         .extid_end = -1UL,
  27         .handler = NULL,
  28 };
  29 #endif
  30
  31 struct kvm_riscv_sbi_extension_entry {
  32         enum KVM_RISCV_SBI_EXT_ID ext_idx;
  33         const struct kvm_vcpu_sbi_extension *ext_ptr;
  34 };
  35
  36 static const struct kvm_riscv_sbi_extension_entry sbi_ext[] = {
  37         {
  38                 .ext_idx = KVM_RISCV_SBI_EXT_V01,
  39                 .ext_ptr = &vcpu_sbi_ext_v01,
  40         },
  41         {
  42                 .ext_idx = KVM_RISCV_SBI_EXT_MAX, /* Can't be disabled */
  43                 .ext_ptr = &vcpu_sbi_ext_base,
  44         },
  45         {
  46                 .ext_idx = KVM_RISCV_SBI_EXT_TIME,
  47                 .ext_ptr = &vcpu_sbi_ext_time,
  48         },
  49         {
  50                 .ext_idx = KVM_RISCV_SBI_EXT_IPI,
  51                 .ext_ptr = &vcpu_sbi_ext_ipi,
  52         },
  53         {
  54                 .ext_idx = KVM_RISCV_SBI_EXT_RFENCE,
  55                 .ext_ptr = &vcpu_sbi_ext_rfence,
  56         },
  57         {
  58                 .ext_idx = KVM_RISCV_SBI_EXT_SRST,
  59                 .ext_ptr = &vcpu_sbi_ext_srst,
  60         },
  61         {
  62                 .ext_idx = KVM_RISCV_SBI_EXT_HSM,
  63                 .ext_ptr = &vcpu_sbi_ext_hsm,
  64         },
  65         {
  66                 .ext_idx = KVM_RISCV_SBI_EXT_PMU,
  67                 .ext_ptr = &vcpu_sbi_ext_pmu,
  68         },
  69         {
  70                 .ext_idx = KVM_RISCV_SBI_EXT_DBCN,
  71                 .ext_ptr = &vcpu_sbi_ext_dbcn,
  72         },
  73         {
  74                 .ext_idx = KVM_RISCV_SBI_EXT_STA,
  75                 .ext_ptr = &vcpu_sbi_ext_sta,
  76         },
  77         {
  78                 .ext_idx = KVM_RISCV_SBI_EXT_EXPERIMENTAL,
  79                 .ext_ptr = &vcpu_sbi_ext_experimental,
  80         },
  81         {
  82                 .ext_idx = KVM_RISCV_SBI_EXT_VENDOR,
  83                 .ext_ptr = &vcpu_sbi_ext_vendor,
  84         },
  85 };
  86
  87 static const struct kvm_riscv_sbi_extension_entry *
  88 riscv_vcpu_get_sbi_ext(struct kvm_vcpu *vcpu, unsigned long idx)
  89 {
  90         const struct kvm_riscv_sbi_extension_entry *sext = NULL;
  91
  92         if (idx >= KVM_RISCV_SBI_EXT_MAX)
  93                 return NULL;
  94
  95         for (int i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
  96                 if (sbi_ext[i].ext_idx == idx) {
  97                         sext = &sbi_ext[i];
  98                         break;
  99                 }
 100         }
 101
 102         return sext;
 103 }
 104
 105 bool riscv_vcpu_supports_sbi_ext(struct kvm_vcpu *vcpu, int idx)
 106 {
 107         struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
 108         const struct kvm_riscv_sbi_extension_entry *sext;
 109
 110         sext = riscv_vcpu_get_sbi_ext(vcpu, idx);
 111
 112         return sext && scontext->ext_status[sext->ext_idx] != KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
 113 }
 114
 115 void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
 116 {
 117         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
 118
 119         vcpu->arch.sbi_context.return_handled = 0;
 120         vcpu->stat.ecall_exit_stat++;
 121         run->exit_reason = KVM_EXIT_RISCV_SBI;
 122         run->riscv_sbi.extension_id = cp->a7;
 123         run->riscv_sbi.function_id = cp->a6;
 124         run->riscv_sbi.args[0] = cp->a0;
 125         run->riscv_sbi.args[1] = cp->a1;
 126         run->riscv_sbi.args[2] = cp->a2;
 127         run->riscv_sbi.args[3] = cp->a3;
 128         run->riscv_sbi.args[4] = cp->a4;
 129         run->riscv_sbi.args[5] = cp->a5;
 130         run->riscv_sbi.ret[0] = SBI_ERR_NOT_SUPPORTED;
 131         run->riscv_sbi.ret[1] = 0;
 132 }
 133
 134 void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
 135                                      struct kvm_run *run,
 136                                      u32 type, u64 reason)
 137 {
 138         unsigned long i;
 139         struct kvm_vcpu *tmp;
 140
 141         kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
 142                 spin_lock(&vcpu->arch.mp_state_lock);
 143                 WRITE_ONCE(tmp->arch.mp_state.mp_state, KVM_MP_STATE_STOPPED);
 144                 spin_unlock(&vcpu->arch.mp_state_lock);
 145         }
 146         kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
 147
 148         memset(&run->system_event, 0, sizeof(run->system_event));
 149         run->system_event.type = type;
 150         run->system_event.ndata = 1;
 151         run->system_event.data[0] = reason;
 152         run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
 153 }
 154
 155 int kvm_riscv_vcpu_sbi_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
 156 {
 157         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
 158
 159         /* Handle SBI return only once */
 160         if (vcpu->arch.sbi_context.return_handled)
 161                 return 0;
 162         vcpu->arch.sbi_context.return_handled = 1;
 163
 164         /* Update return values */
 165         cp->a0 = run->riscv_sbi.ret[0];
 166         cp->a1 = run->riscv_sbi.ret[1];
 167
 168         /* Move to next instruction */
 169         vcpu->arch.guest_context.sepc += 4;
 170
 171         return 0;
 172 }
 173
 174 static int riscv_vcpu_set_sbi_ext_single(struct kvm_vcpu *vcpu,
 175                                          unsigned long reg_num,
 176                                          unsigned long reg_val)
 177 {
 178         struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
 179         const struct kvm_riscv_sbi_extension_entry *sext;
 180
 181         if (reg_val != 1 && reg_val != 0)
 182                 return -EINVAL;
 183
 184         sext = riscv_vcpu_get_sbi_ext(vcpu, reg_num);
 185         if (!sext || scontext->ext_status[sext->ext_idx] == KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE)
 186                 return -ENOENT;
 187
 188         scontext->ext_status[sext->ext_idx] = (reg_val) ?
 189                         KVM_RISCV_SBI_EXT_STATUS_ENABLED :
 190                         KVM_RISCV_SBI_EXT_STATUS_DISABLED;
 191
 192         return 0;
 193 }
 194
 195 static int riscv_vcpu_get_sbi_ext_single(struct kvm_vcpu *vcpu,
 196                                          unsigned long reg_num,
 197                                          unsigned long *reg_val)
 198 {
 199         struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
 200         const struct kvm_riscv_sbi_extension_entry *sext;
 201
 202         sext = riscv_vcpu_get_sbi_ext(vcpu, reg_num);
 203         if (!sext || scontext->ext_status[sext->ext_idx] == KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE)
 204                 return -ENOENT;
 205
 206         *reg_val = scontext->ext_status[sext->ext_idx] ==
 207                                 KVM_RISCV_SBI_EXT_STATUS_ENABLED;
 208
 209         return 0;
 210 }
 211
 212 static int riscv_vcpu_set_sbi_ext_multi(struct kvm_vcpu *vcpu,
 213                                         unsigned long reg_num,
 214                                         unsigned long reg_val, bool enable)
 215 {
 216         unsigned long i, ext_id;
 217
 218         if (reg_num > KVM_REG_RISCV_SBI_MULTI_REG_LAST)
 219                 return -ENOENT;
 220
 221         for_each_set_bit(i, &reg_val, BITS_PER_LONG) {
 222                 ext_id = i + reg_num * BITS_PER_LONG;
 223                 if (ext_id >= KVM_RISCV_SBI_EXT_MAX)
 224                         break;
 225
 226                 riscv_vcpu_set_sbi_ext_single(vcpu, ext_id, enable);
 227         }
 228
 229         return 0;
 230 }
 231
 232 static int riscv_vcpu_get_sbi_ext_multi(struct kvm_vcpu *vcpu,
 233                                         unsigned long reg_num,
 234                                         unsigned long *reg_val)
 235 {
 236         unsigned long i, ext_id, ext_val;
 237
 238         if (reg_num > KVM_REG_RISCV_SBI_MULTI_REG_LAST)
 239                 return -ENOENT;
 240
 241         for (i = 0; i < BITS_PER_LONG; i++) {
 242                 ext_id = i + reg_num * BITS_PER_LONG;
 243                 if (ext_id >= KVM_RISCV_SBI_EXT_MAX)
 244                         break;
 245
 246                 ext_val = 0;
 247                 riscv_vcpu_get_sbi_ext_single(vcpu, ext_id, &ext_val);
 248                 if (ext_val)
 249                         *reg_val |= KVM_REG_RISCV_SBI_MULTI_MASK(ext_id);
 250         }
 251
 252         return 0;
 253 }
 254
 255 int kvm_riscv_vcpu_set_reg_sbi_ext(struct kvm_vcpu *vcpu,
 256                                    const struct kvm_one_reg *reg)
 257 {
 258         unsigned long __user *uaddr =
 259                         (unsigned long __user *)(unsigned long)reg->addr;
 260         unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
 261                                             KVM_REG_SIZE_MASK |
 262                                             KVM_REG_RISCV_SBI_EXT);
 263         unsigned long reg_val, reg_subtype;
 264
 265         if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
 266                 return -EINVAL;
 267
 268         if (vcpu->arch.ran_atleast_once)
 269                 return -EBUSY;
 270
 271         reg_subtype = reg_num & KVM_REG_RISCV_SUBTYPE_MASK;
 272         reg_num &= ~KVM_REG_RISCV_SUBTYPE_MASK;
 273
 274         if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
 275                 return -EFAULT;
 276
 277         switch (reg_subtype) {
 278         case KVM_REG_RISCV_SBI_SINGLE:
 279                 return riscv_vcpu_set_sbi_ext_single(vcpu, reg_num, reg_val);
 280         case KVM_REG_RISCV_SBI_MULTI_EN:
 281                 return riscv_vcpu_set_sbi_ext_multi(vcpu, reg_num, reg_val, true);
 282         case KVM_REG_RISCV_SBI_MULTI_DIS:
 283                 return riscv_vcpu_set_sbi_ext_multi(vcpu, reg_num, reg_val, false);
 284         default:
 285                 return -ENOENT;
 286         }
 287
 288         return 0;
 289 }
 290
 291 int kvm_riscv_vcpu_get_reg_sbi_ext(struct kvm_vcpu *vcpu,
 292                                    const struct kvm_one_reg *reg)
 293 {
 294         int rc;
 295         unsigned long __user *uaddr =
 296                         (unsigned long __user *)(unsigned long)reg->addr;
 297         unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
 298                                             KVM_REG_SIZE_MASK |
 299                                             KVM_REG_RISCV_SBI_EXT);
 300         unsigned long reg_val, reg_subtype;
 301
 302         if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
 303                 return -EINVAL;
 304
 305         reg_subtype = reg_num & KVM_REG_RISCV_SUBTYPE_MASK;
 306         reg_num &= ~KVM_REG_RISCV_SUBTYPE_MASK;
 307
 308         reg_val = 0;
 309         switch (reg_subtype) {
 310         case KVM_REG_RISCV_SBI_SINGLE:
 311                 rc = riscv_vcpu_get_sbi_ext_single(vcpu, reg_num, &reg_val);
 312                 break;
 313         case KVM_REG_RISCV_SBI_MULTI_EN:
 314         case KVM_REG_RISCV_SBI_MULTI_DIS:
 315                 rc = riscv_vcpu_get_sbi_ext_multi(vcpu, reg_num, &reg_val);
 316                 if (!rc && reg_subtype == KVM_REG_RISCV_SBI_MULTI_DIS)
 317                         reg_val = ~reg_val;
 318                 break;
 319         default:
 320                 rc = -ENOENT;
 321         }
 322         if (rc)
 323                 return rc;
 324
 325         if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
 326                 return -EFAULT;
 327
 328         return 0;
 329 }
 330
 331 int kvm_riscv_vcpu_set_reg_sbi(struct kvm_vcpu *vcpu,
 332                                const struct kvm_one_reg *reg)
 333 {
 334         unsigned long __user *uaddr =
 335                         (unsigned long __user *)(unsigned long)reg->addr;
 336         unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
 337                                             KVM_REG_SIZE_MASK |
 338                                             KVM_REG_RISCV_SBI_STATE);
 339         unsigned long reg_subtype, reg_val;
 340
 341         if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
 342                 return -EINVAL;
 343
 344         if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
 345                 return -EFAULT;
 346
 347         reg_subtype = reg_num & KVM_REG_RISCV_SUBTYPE_MASK;
 348         reg_num &= ~KVM_REG_RISCV_SUBTYPE_MASK;
 349
 350         switch (reg_subtype) {
 351         case KVM_REG_RISCV_SBI_STA:
 352                 return kvm_riscv_vcpu_set_reg_sbi_sta(vcpu, reg_num, reg_val);
 353         default:
 354                 return -EINVAL;
 355         }
 356
 357         return 0;
 358 }
 359
 360 int kvm_riscv_vcpu_get_reg_sbi(struct kvm_vcpu *vcpu,
 361                                const struct kvm_one_reg *reg)
 362 {
 363         unsigned long __user *uaddr =
 364                         (unsigned long __user *)(unsigned long)reg->addr;
 365         unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
 366                                             KVM_REG_SIZE_MASK |
 367                                             KVM_REG_RISCV_SBI_STATE);
 368         unsigned long reg_subtype, reg_val;
 369         int ret;
 370
 371         if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
 372                 return -EINVAL;
 373
 374         reg_subtype = reg_num & KVM_REG_RISCV_SUBTYPE_MASK;
 375         reg_num &= ~KVM_REG_RISCV_SUBTYPE_MASK;
 376
 377         switch (reg_subtype) {
 378         case KVM_REG_RISCV_SBI_STA:
 379                 ret = kvm_riscv_vcpu_get_reg_sbi_sta(vcpu, reg_num, &reg_val);
 380                 break;
 381         default:
 382                 return -EINVAL;
 383         }
 384
 385         if (ret)
 386                 return ret;
 387
 388         if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
 389                 return -EFAULT;
 390
 391         return 0;
 392 }
 393
 394 const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext(
 395                                 struct kvm_vcpu *vcpu, unsigned long extid)
 396 {
 397         struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
 398         const struct kvm_riscv_sbi_extension_entry *entry;
 399         const struct kvm_vcpu_sbi_extension *ext;
 400         int i;
 401
 402         for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
 403                 entry = &sbi_ext[i];
 404                 ext = entry->ext_ptr;
 405
 406                 if (ext->extid_start <= extid && ext->extid_end >= extid) {
 407                         if (entry->ext_idx >= KVM_RISCV_SBI_EXT_MAX ||
 408                             scontext->ext_status[entry->ext_idx] ==
 409                                                 KVM_RISCV_SBI_EXT_STATUS_ENABLED)
 410                                 return ext;
 411
 412                         return NULL;
 413                 }
 414         }
 415
 416         return NULL;
 417 }
 418
 419 int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
 420 {
 421         int ret = 1;
 422         bool next_sepc = true;
 423         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
 424         const struct kvm_vcpu_sbi_extension *sbi_ext;
 425         struct kvm_cpu_trap utrap = {0};
 426         struct kvm_vcpu_sbi_return sbi_ret = {
 427                 .out_val = 0,
 428                 .err_val = 0,
 429                 .utrap = &utrap,
 430         };
 431         bool ext_is_v01 = false;
 432
 433         sbi_ext = kvm_vcpu_sbi_find_ext(vcpu, cp->a7);
 434         if (sbi_ext && sbi_ext->handler) {
 435 #ifdef CONFIG_RISCV_SBI_V01
 436                 if (cp->a7 >= SBI_EXT_0_1_SET_TIMER &&
 437                     cp->a7 <= SBI_EXT_0_1_SHUTDOWN)
 438                         ext_is_v01 = true;
 439 #endif
 440                 ret = sbi_ext->handler(vcpu, run, &sbi_ret);
 441         } else {
 442                 /* Return error for unsupported SBI calls */
 443                 cp->a0 = SBI_ERR_NOT_SUPPORTED;
 444                 goto ecall_done;
 445         }
 446
 447         /*
 448          * When the SBI extension returns a Linux error code, it exits the ioctl
 449          * loop and forwards the error to userspace.
 450          */
 451         if (ret < 0) {
 452                 next_sepc = false;
 453                 goto ecall_done;
 454         }
 455
 456         /* Handle special error cases i.e trap, exit or userspace forward */
 457         if (sbi_ret.utrap->scause) {
 458                 /* No need to increment sepc or exit ioctl loop */
 459                 ret = 1;
 460                 sbi_ret.utrap->sepc = cp->sepc;
 461                 kvm_riscv_vcpu_trap_redirect(vcpu, sbi_ret.utrap);
 462                 next_sepc = false;
 463                 goto ecall_done;
 464         }
 465
 466         /* Exit ioctl loop or Propagate the error code the guest */
 467         if (sbi_ret.uexit) {
 468                 next_sepc = false;
 469                 ret = 0;
 470         } else {
 471                 cp->a0 = sbi_ret.err_val;
 472                 ret = 1;
 473         }
 474 ecall_done:
 475         if (next_sepc)
 476                 cp->sepc += 4;
 477         /* a1 should only be updated when we continue the ioctl loop */
 478         if (!ext_is_v01 && ret == 1)
 479                 cp->a1 = sbi_ret.out_val;
 480
 481         return ret;
 482 }
 483
 484 void kvm_riscv_vcpu_sbi_init(struct kvm_vcpu *vcpu)
 485 {
 486         struct kvm_vcpu_sbi_context *scontext = &vcpu->arch.sbi_context;
 487         const struct kvm_riscv_sbi_extension_entry *entry;
 488         const struct kvm_vcpu_sbi_extension *ext;
 489         int idx, i;
 490
 491         for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
 492                 entry = &sbi_ext[i];
 493                 ext = entry->ext_ptr;
 494                 idx = entry->ext_idx;
 495
 496                 if (idx < 0 || idx >= ARRAY_SIZE(scontext->ext_status))
 497                         continue;
 498
 499                 if (ext->probe && !ext->probe(vcpu)) {
 500                         scontext->ext_status[idx] = KVM_RISCV_SBI_EXT_STATUS_UNAVAILABLE;
 501                         continue;
 502                 }
 503
 504                 scontext->ext_status[idx] = ext->default_disabled ?
 505                                         KVM_RISCV_SBI_EXT_STATUS_DISABLED :
 506                                         KVM_RISCV_SBI_EXT_STATUS_ENABLED;
 507         }
 508 }