virt/kvm/arm/psci.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 - ARM Ltd
   4  * Author: Marc Zyngier <marc.zyngier@arm.com>
   5  */
   6
   7 #include <linux/arm-smccc.h>
   8 #include <linux/preempt.h>
   9 #include <linux/kvm_host.h>
  10 #include <linux/uaccess.h>
  11 #include <linux/wait.h>
  12
  13 #include <asm/cputype.h>
  14 #include <asm/kvm_emulate.h>
  15 #include <asm/kvm_host.h>
  16
  17 #include <kvm/arm_psci.h>
  18 #include <kvm/arm_hypercalls.h>
  19
  20 /*
  21  * This is an implementation of the Power State Coordination Interface
  22  * as described in ARM document number ARM DEN 0022A.
  23  */
  24
  25 #define AFFINITY_MASK(level)    ~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
  26
  27 static unsigned long psci_affinity_mask(unsigned long affinity_level)
  28 {
  29         if (affinity_level <= 3)
  30                 return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);
  31
  32         return 0;
  33 }
  34
  35 static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
  36 {
  37         /*
  38          * NOTE: For simplicity, we make VCPU suspend emulation to be
  39          * same-as WFI (Wait-for-interrupt) emulation.
  40          *
  41          * This means for KVM the wakeup events are interrupts and
  42          * this is consistent with intended use of StateID as described
  43          * in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
  44          *
  45          * Further, we also treat power-down request to be same as
  46          * stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
  47          * specification (ARM DEN 0022A). This means all suspend states
  48          * for KVM will preserve the register state.
  49          */
  50         kvm_vcpu_block(vcpu);
  51         kvm_clear_request(KVM_REQ_UNHALT, vcpu);
  52
  53         return PSCI_RET_SUCCESS;
  54 }
  55
  56 static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
  57 {
  58         vcpu->arch.power_off = true;
  59         kvm_make_request(KVM_REQ_SLEEP, vcpu);
  60         kvm_vcpu_kick(vcpu);
  61 }
  62
  63 static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
  64 {
  65         struct vcpu_reset_state *reset_state;
  66         struct kvm *kvm = source_vcpu->kvm;
  67         struct kvm_vcpu *vcpu = NULL;
  68         unsigned long cpu_id;
  69
  70         cpu_id = smccc_get_arg1(source_vcpu) & MPIDR_HWID_BITMASK;
  71         if (vcpu_mode_is_32bit(source_vcpu))
  72                 cpu_id &= ~((u32) 0);
  73
  74         vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);
  75
  76         /*
  77          * Make sure the caller requested a valid CPU and that the CPU is
  78          * turned off.
  79          */
  80         if (!vcpu)
  81                 return PSCI_RET_INVALID_PARAMS;
  82         if (!vcpu->arch.power_off) {
  83                 if (kvm_psci_version(source_vcpu, kvm) != KVM_ARM_PSCI_0_1)
  84                         return PSCI_RET_ALREADY_ON;
  85                 else
  86                         return PSCI_RET_INVALID_PARAMS;
  87         }
  88
  89         reset_state = &vcpu->arch.reset_state;
  90
  91         reset_state->pc = smccc_get_arg2(source_vcpu);
  92
  93         /* Propagate caller endianness */
  94         reset_state->be = kvm_vcpu_is_be(source_vcpu);
  95
  96         /*
  97          * NOTE: We always update r0 (or x0) because for PSCI v0.1
  98          * the general puspose registers are undefined upon CPU_ON.
  99          */
 100         reset_state->r0 = smccc_get_arg3(source_vcpu);
 101
 102         WRITE_ONCE(reset_state->reset, true);
 103         kvm_make_request(KVM_REQ_VCPU_RESET, vcpu);
 104
 105         /*
 106          * Make sure the reset request is observed if the change to
 107          * power_state is observed.
 108          */
 109         smp_wmb();
 110
 111         vcpu->arch.power_off = false;
 112         kvm_vcpu_wake_up(vcpu);
 113
 114         return PSCI_RET_SUCCESS;
 115 }
 116
 117 static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
 118 {
 119         int i, matching_cpus = 0;
 120         unsigned long mpidr;
 121         unsigned long target_affinity;
 122         unsigned long target_affinity_mask;
 123         unsigned long lowest_affinity_level;
 124         struct kvm *kvm = vcpu->kvm;
 125         struct kvm_vcpu *tmp;
 126
 127         target_affinity = smccc_get_arg1(vcpu);
 128         lowest_affinity_level = smccc_get_arg2(vcpu);
 129
 130         /* Determine target affinity mask */
 131         target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
 132         if (!target_affinity_mask)
 133                 return PSCI_RET_INVALID_PARAMS;
 134
 135         /* Ignore other bits of target affinity */
 136         target_affinity &= target_affinity_mask;
 137
 138         /*
 139          * If one or more VCPU matching target affinity are running
 140          * then ON else OFF
 141          */
 142         kvm_for_each_vcpu(i, tmp, kvm) {
 143                 mpidr = kvm_vcpu_get_mpidr_aff(tmp);
 144                 if ((mpidr & target_affinity_mask) == target_affinity) {
 145                         matching_cpus++;
 146                         if (!tmp->arch.power_off)
 147                                 return PSCI_0_2_AFFINITY_LEVEL_ON;
 148                 }
 149         }
 150
 151         if (!matching_cpus)
 152                 return PSCI_RET_INVALID_PARAMS;
 153
 154         return PSCI_0_2_AFFINITY_LEVEL_OFF;
 155 }
 156
 157 static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
 158 {
 159         int i;
 160         struct kvm_vcpu *tmp;
 161
 162         /*
 163          * The KVM ABI specifies that a system event exit may call KVM_RUN
 164          * again and may perform shutdown/reboot at a later time that when the
 165          * actual request is made.  Since we are implementing PSCI and a
 166          * caller of PSCI reboot and shutdown expects that the system shuts
 167          * down or reboots immediately, let's make sure that VCPUs are not run
 168          * after this call is handled and before the VCPUs have been
 169          * re-initialized.
 170          */
 171         kvm_for_each_vcpu(i, tmp, vcpu->kvm)
 172                 tmp->arch.power_off = true;
 173         kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
 174
 175         memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
 176         vcpu->run->system_event.type = type;
 177         vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
 178 }
 179
 180 static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
 181 {
 182         kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
 183 }
 184
 185 static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
 186 {
 187         kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
 188 }
 189
 190 static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
 191 {
 192         struct kvm *kvm = vcpu->kvm;
 193         u32 psci_fn = smccc_get_function(vcpu);
 194         unsigned long val;
 195         int ret = 1;
 196
 197         switch (psci_fn) {
 198         case PSCI_0_2_FN_PSCI_VERSION:
 199                 /*
 200                  * Bits[31:16] = Major Version = 0
 201                  * Bits[15:0] = Minor Version = 2
 202                  */
 203                 val = KVM_ARM_PSCI_0_2;
 204                 break;
 205         case PSCI_0_2_FN_CPU_SUSPEND:
 206         case PSCI_0_2_FN64_CPU_SUSPEND:
 207                 val = kvm_psci_vcpu_suspend(vcpu);
 208                 break;
 209         case PSCI_0_2_FN_CPU_OFF:
 210                 kvm_psci_vcpu_off(vcpu);
 211                 val = PSCI_RET_SUCCESS;
 212                 break;
 213         case PSCI_0_2_FN_CPU_ON:
 214         case PSCI_0_2_FN64_CPU_ON:
 215                 mutex_lock(&kvm->lock);
 216                 val = kvm_psci_vcpu_on(vcpu);
 217                 mutex_unlock(&kvm->lock);
 218                 break;
 219         case PSCI_0_2_FN_AFFINITY_INFO:
 220         case PSCI_0_2_FN64_AFFINITY_INFO:
 221                 val = kvm_psci_vcpu_affinity_info(vcpu);
 222                 break;
 223         case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
 224                 /*
 225                  * Trusted OS is MP hence does not require migration
 226                  * or
 227                  * Trusted OS is not present
 228                  */
 229                 val = PSCI_0_2_TOS_MP;
 230                 break;
 231         case PSCI_0_2_FN_SYSTEM_OFF:
 232                 kvm_psci_system_off(vcpu);
 233                 /*
 234                  * We should'nt be going back to guest VCPU after
 235                  * receiving SYSTEM_OFF request.
 236                  *
 237                  * If user space accidently/deliberately resumes
 238                  * guest VCPU after SYSTEM_OFF request then guest
 239                  * VCPU should see internal failure from PSCI return
 240                  * value. To achieve this, we preload r0 (or x0) with
 241                  * PSCI return value INTERNAL_FAILURE.
 242                  */
 243                 val = PSCI_RET_INTERNAL_FAILURE;
 244                 ret = 0;
 245                 break;
 246         case PSCI_0_2_FN_SYSTEM_RESET:
 247                 kvm_psci_system_reset(vcpu);
 248                 /*
 249                  * Same reason as SYSTEM_OFF for preloading r0 (or x0)
 250                  * with PSCI return value INTERNAL_FAILURE.
 251                  */
 252                 val = PSCI_RET_INTERNAL_FAILURE;
 253                 ret = 0;
 254                 break;
 255         default:
 256                 val = PSCI_RET_NOT_SUPPORTED;
 257                 break;
 258         }
 259
 260         smccc_set_retval(vcpu, val, 0, 0, 0);
 261         return ret;
 262 }
 263
 264 static int kvm_psci_1_0_call(struct kvm_vcpu *vcpu)
 265 {
 266         u32 psci_fn = smccc_get_function(vcpu);
 267         u32 feature;
 268         unsigned long val;
 269         int ret = 1;
 270
 271         switch(psci_fn) {
 272         case PSCI_0_2_FN_PSCI_VERSION:
 273                 val = KVM_ARM_PSCI_1_0;
 274                 break;
 275         case PSCI_1_0_FN_PSCI_FEATURES:
 276                 feature = smccc_get_arg1(vcpu);
 277                 switch(feature) {
 278                 case PSCI_0_2_FN_PSCI_VERSION:
 279                 case PSCI_0_2_FN_CPU_SUSPEND:
 280                 case PSCI_0_2_FN64_CPU_SUSPEND:
 281                 case PSCI_0_2_FN_CPU_OFF:
 282                 case PSCI_0_2_FN_CPU_ON:
 283                 case PSCI_0_2_FN64_CPU_ON:
 284                 case PSCI_0_2_FN_AFFINITY_INFO:
 285                 case PSCI_0_2_FN64_AFFINITY_INFO:
 286                 case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
 287                 case PSCI_0_2_FN_SYSTEM_OFF:
 288                 case PSCI_0_2_FN_SYSTEM_RESET:
 289                 case PSCI_1_0_FN_PSCI_FEATURES:
 290                 case ARM_SMCCC_VERSION_FUNC_ID:
 291                         val = 0;
 292                         break;
 293                 default:
 294                         val = PSCI_RET_NOT_SUPPORTED;
 295                         break;
 296                 }
 297                 break;
 298         default:
 299                 return kvm_psci_0_2_call(vcpu);
 300         }
 301
 302         smccc_set_retval(vcpu, val, 0, 0, 0);
 303         return ret;
 304 }
 305
 306 static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
 307 {
 308         struct kvm *kvm = vcpu->kvm;
 309         u32 psci_fn = smccc_get_function(vcpu);
 310         unsigned long val;
 311
 312         switch (psci_fn) {
 313         case KVM_PSCI_FN_CPU_OFF:
 314                 kvm_psci_vcpu_off(vcpu);
 315                 val = PSCI_RET_SUCCESS;
 316                 break;
 317         case KVM_PSCI_FN_CPU_ON:
 318                 mutex_lock(&kvm->lock);
 319                 val = kvm_psci_vcpu_on(vcpu);
 320                 mutex_unlock(&kvm->lock);
 321                 break;
 322         default:
 323                 val = PSCI_RET_NOT_SUPPORTED;
 324                 break;
 325         }
 326
 327         smccc_set_retval(vcpu, val, 0, 0, 0);
 328         return 1;
 329 }
 330
 331 /**
 332  * kvm_psci_call - handle PSCI call if r0 value is in range
 333  * @vcpu: Pointer to the VCPU struct
 334  *
 335  * Handle PSCI calls from guests through traps from HVC instructions.
 336  * The calling convention is similar to SMC calls to the secure world
 337  * where the function number is placed in r0.
 338  *
 339  * This function returns: > 0 (success), 0 (success but exit to user
 340  * space), and < 0 (errors)
 341  *
 342  * Errors:
 343  * -EINVAL: Unrecognized PSCI function
 344  */
 345 int kvm_psci_call(struct kvm_vcpu *vcpu)
 346 {
 347         switch (kvm_psci_version(vcpu, vcpu->kvm)) {
 348         case KVM_ARM_PSCI_1_0:
 349                 return kvm_psci_1_0_call(vcpu);
 350         case KVM_ARM_PSCI_0_2:
 351                 return kvm_psci_0_2_call(vcpu);
 352         case KVM_ARM_PSCI_0_1:
 353                 return kvm_psci_0_1_call(vcpu);
 354         default:
 355                 return -EINVAL;
 356         };
 357 }
 358
 359 int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
 360 {
 361         return 3;               /* PSCI version and two workaround registers */
 362 }
 363
 364 int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
 365 {
 366         if (put_user(KVM_REG_ARM_PSCI_VERSION, uindices++))
 367                 return -EFAULT;
 368
 369         if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1, uindices++))
 370                 return -EFAULT;
 371
 372         if (put_user(KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2, uindices++))
 373                 return -EFAULT;
 374
 375         return 0;
 376 }
 377
 378 #define KVM_REG_FEATURE_LEVEL_WIDTH     4
 379 #define KVM_REG_FEATURE_LEVEL_MASK      (BIT(KVM_REG_FEATURE_LEVEL_WIDTH) - 1)
 380
 381 /*
 382  * Convert the workaround level into an easy-to-compare number, where higher
 383  * values mean better protection.
 384  */
 385 static int get_kernel_wa_level(u64 regid)
 386 {
 387         switch (regid) {
 388         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
 389                 switch (kvm_arm_harden_branch_predictor()) {
 390                 case KVM_BP_HARDEN_UNKNOWN:
 391                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
 392                 case KVM_BP_HARDEN_WA_NEEDED:
 393                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL;
 394                 case KVM_BP_HARDEN_NOT_REQUIRED:
 395                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED;
 396                 }
 397                 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
 398         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
 399                 switch (kvm_arm_have_ssbd()) {
 400                 case KVM_SSBD_FORCE_DISABLE:
 401                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
 402                 case KVM_SSBD_KERNEL:
 403                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL;
 404                 case KVM_SSBD_FORCE_ENABLE:
 405                 case KVM_SSBD_MITIGATED:
 406                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
 407                 case KVM_SSBD_UNKNOWN:
 408                 default:
 409                         return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN;
 410                 }
 411         }
 412
 413         return -EINVAL;
 414 }
 415
 416 int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 417 {
 418         void __user *uaddr = (void __user *)(long)reg->addr;
 419         u64 val;
 420
 421         switch (reg->id) {
 422         case KVM_REG_ARM_PSCI_VERSION:
 423                 val = kvm_psci_version(vcpu, vcpu->kvm);
 424                 break;
 425         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
 426                 val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
 427                 break;
 428         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
 429                 val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
 430
 431                 if (val == KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL &&
 432                     kvm_arm_get_vcpu_workaround_2_flag(vcpu))
 433                         val |= KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED;
 434                 break;
 435         default:
 436                 return -ENOENT;
 437         }
 438
 439         if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
 440                 return -EFAULT;
 441
 442         return 0;
 443 }
 444
 445 int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 446 {
 447         void __user *uaddr = (void __user *)(long)reg->addr;
 448         u64 val;
 449         int wa_level;
 450
 451         if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
 452                 return -EFAULT;
 453
 454         switch (reg->id) {
 455         case KVM_REG_ARM_PSCI_VERSION:
 456         {
 457                 bool wants_02;
 458
 459                 wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features);
 460
 461                 switch (val) {
 462                 case KVM_ARM_PSCI_0_1:
 463                         if (wants_02)
 464                                 return -EINVAL;
 465                         vcpu->kvm->arch.psci_version = val;
 466                         return 0;
 467                 case KVM_ARM_PSCI_0_2:
 468                 case KVM_ARM_PSCI_1_0:
 469                         if (!wants_02)
 470                                 return -EINVAL;
 471                         vcpu->kvm->arch.psci_version = val;
 472                         return 0;
 473                 }
 474                 break;
 475         }
 476
 477         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
 478                 if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
 479                         return -EINVAL;
 480
 481                 if (get_kernel_wa_level(reg->id) < val)
 482                         return -EINVAL;
 483
 484                 return 0;
 485
 486         case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
 487                 if (val & ~(KVM_REG_FEATURE_LEVEL_MASK |
 488                             KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED))
 489                         return -EINVAL;
 490
 491                 wa_level = val & KVM_REG_FEATURE_LEVEL_MASK;
 492
 493                 if (get_kernel_wa_level(reg->id) < wa_level)
 494                         return -EINVAL;
 495
 496                 /* The enabled bit must not be set unless the level is AVAIL. */
 497                 if (wa_level != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL &&
 498                     wa_level != val)
 499                         return -EINVAL;
 500
 501                 /* Are we finished or do we need to check the enable bit ? */
 502                 if (kvm_arm_have_ssbd() != KVM_SSBD_KERNEL)
 503                         return 0;
 504
 505                 /*
 506                  * If this kernel supports the workaround to be switched on
 507                  * or off, make sure it matches the requested setting.
 508                  */
 509                 switch (wa_level) {
 510                 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
 511                         kvm_arm_set_vcpu_workaround_2_flag(vcpu,
 512                             val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED);
 513                         break;
 514                 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
 515                         kvm_arm_set_vcpu_workaround_2_flag(vcpu, true);
 516                         break;
 517                 }
 518
 519                 return 0;
 520         default:
 521                 return -ENOENT;
 522         }
 523
 524         return -EINVAL;
 525 }