virt/kvm/arm/psci.c

   1 /*
   2  * Copyright (C) 2012 - ARM Ltd
   3  * Author: Marc Zyngier <marc.zyngier@arm.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <linux/arm-smccc.h>
  19 #include <linux/preempt.h>
  20 #include <linux/kvm_host.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/wait.h>
  23
  24 #include <asm/cputype.h>
  25 #include <asm/kvm_emulate.h>
  26 #include <asm/kvm_host.h>
  27
  28 #include <kvm/arm_psci.h>
  29
  30 /*
  31  * This is an implementation of the Power State Coordination Interface
  32  * as described in ARM document number ARM DEN 0022A.
  33  */
  34
  35 #define AFFINITY_MASK(level)    ~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
  36
  37 static u32 smccc_get_function(struct kvm_vcpu *vcpu)
  38 {
  39         return vcpu_get_reg(vcpu, 0);
  40 }
  41
  42 static unsigned long smccc_get_arg1(struct kvm_vcpu *vcpu)
  43 {
  44         return vcpu_get_reg(vcpu, 1);
  45 }
  46
  47 static unsigned long smccc_get_arg2(struct kvm_vcpu *vcpu)
  48 {
  49         return vcpu_get_reg(vcpu, 2);
  50 }
  51
  52 static unsigned long smccc_get_arg3(struct kvm_vcpu *vcpu)
  53 {
  54         return vcpu_get_reg(vcpu, 3);
  55 }
  56
  57 static void smccc_set_retval(struct kvm_vcpu *vcpu,
  58                              unsigned long a0,
  59                              unsigned long a1,
  60                              unsigned long a2,
  61                              unsigned long a3)
  62 {
  63         vcpu_set_reg(vcpu, 0, a0);
  64         vcpu_set_reg(vcpu, 1, a1);
  65         vcpu_set_reg(vcpu, 2, a2);
  66         vcpu_set_reg(vcpu, 3, a3);
  67 }
  68
  69 static unsigned long psci_affinity_mask(unsigned long affinity_level)
  70 {
  71         if (affinity_level <= 3)
  72                 return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);
  73
  74         return 0;
  75 }
  76
  77 static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
  78 {
  79         /*
  80          * NOTE: For simplicity, we make VCPU suspend emulation to be
  81          * same-as WFI (Wait-for-interrupt) emulation.
  82          *
  83          * This means for KVM the wakeup events are interrupts and
  84          * this is consistent with intended use of StateID as described
  85          * in section 5.4.1 of PSCI v0.2 specification (ARM DEN 0022A).
  86          *
  87          * Further, we also treat power-down request to be same as
  88          * stand-by request as-per section 5.4.2 clause 3 of PSCI v0.2
  89          * specification (ARM DEN 0022A). This means all suspend states
  90          * for KVM will preserve the register state.
  91          */
  92         kvm_vcpu_block(vcpu);
  93         kvm_clear_request(KVM_REQ_UNHALT, vcpu);
  94
  95         return PSCI_RET_SUCCESS;
  96 }
  97
  98 static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
  99 {
 100         vcpu->arch.power_off = true;
 101         kvm_make_request(KVM_REQ_SLEEP, vcpu);
 102         kvm_vcpu_kick(vcpu);
 103 }
 104
 105 static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
 106 {
 107         struct kvm *kvm = source_vcpu->kvm;
 108         struct kvm_vcpu *vcpu = NULL;
 109         struct swait_queue_head *wq;
 110         unsigned long cpu_id;
 111         unsigned long context_id;
 112         phys_addr_t target_pc;
 113
 114         cpu_id = smccc_get_arg1(source_vcpu) & MPIDR_HWID_BITMASK;
 115         if (vcpu_mode_is_32bit(source_vcpu))
 116                 cpu_id &= ~((u32) 0);
 117
 118         vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);
 119
 120         /*
 121          * Make sure the caller requested a valid CPU and that the CPU is
 122          * turned off.
 123          */
 124         if (!vcpu)
 125                 return PSCI_RET_INVALID_PARAMS;
 126         if (!vcpu->arch.power_off) {
 127                 if (kvm_psci_version(source_vcpu, kvm) != KVM_ARM_PSCI_0_1)
 128                         return PSCI_RET_ALREADY_ON;
 129                 else
 130                         return PSCI_RET_INVALID_PARAMS;
 131         }
 132
 133         target_pc = smccc_get_arg2(source_vcpu);
 134         context_id = smccc_get_arg3(source_vcpu);
 135
 136         kvm_reset_vcpu(vcpu);
 137
 138         /* Gracefully handle Thumb2 entry point */
 139         if (vcpu_mode_is_32bit(vcpu) && (target_pc & 1)) {
 140                 target_pc &= ~((phys_addr_t) 1);
 141                 vcpu_set_thumb(vcpu);
 142         }
 143
 144         /* Propagate caller endianness */
 145         if (kvm_vcpu_is_be(source_vcpu))
 146                 kvm_vcpu_set_be(vcpu);
 147
 148         *vcpu_pc(vcpu) = target_pc;
 149         /*
 150          * NOTE: We always update r0 (or x0) because for PSCI v0.1
 151          * the general puspose registers are undefined upon CPU_ON.
 152          */
 153         smccc_set_retval(vcpu, context_id, 0, 0, 0);
 154         vcpu->arch.power_off = false;
 155         smp_mb();               /* Make sure the above is visible */
 156
 157         wq = kvm_arch_vcpu_wq(vcpu);
 158         swake_up(wq);
 159
 160         return PSCI_RET_SUCCESS;
 161 }
 162
 163 static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
 164 {
 165         int i, matching_cpus = 0;
 166         unsigned long mpidr;
 167         unsigned long target_affinity;
 168         unsigned long target_affinity_mask;
 169         unsigned long lowest_affinity_level;
 170         struct kvm *kvm = vcpu->kvm;
 171         struct kvm_vcpu *tmp;
 172
 173         target_affinity = smccc_get_arg1(vcpu);
 174         lowest_affinity_level = smccc_get_arg2(vcpu);
 175
 176         /* Determine target affinity mask */
 177         target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
 178         if (!target_affinity_mask)
 179                 return PSCI_RET_INVALID_PARAMS;
 180
 181         /* Ignore other bits of target affinity */
 182         target_affinity &= target_affinity_mask;
 183
 184         /*
 185          * If one or more VCPU matching target affinity are running
 186          * then ON else OFF
 187          */
 188         kvm_for_each_vcpu(i, tmp, kvm) {
 189                 mpidr = kvm_vcpu_get_mpidr_aff(tmp);
 190                 if ((mpidr & target_affinity_mask) == target_affinity) {
 191                         matching_cpus++;
 192                         if (!tmp->arch.power_off)
 193                                 return PSCI_0_2_AFFINITY_LEVEL_ON;
 194                 }
 195         }
 196
 197         if (!matching_cpus)
 198                 return PSCI_RET_INVALID_PARAMS;
 199
 200         return PSCI_0_2_AFFINITY_LEVEL_OFF;
 201 }
 202
 203 static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
 204 {
 205         int i;
 206         struct kvm_vcpu *tmp;
 207
 208         /*
 209          * The KVM ABI specifies that a system event exit may call KVM_RUN
 210          * again and may perform shutdown/reboot at a later time that when the
 211          * actual request is made.  Since we are implementing PSCI and a
 212          * caller of PSCI reboot and shutdown expects that the system shuts
 213          * down or reboots immediately, let's make sure that VCPUs are not run
 214          * after this call is handled and before the VCPUs have been
 215          * re-initialized.
 216          */
 217         kvm_for_each_vcpu(i, tmp, vcpu->kvm)
 218                 tmp->arch.power_off = true;
 219         kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
 220
 221         memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
 222         vcpu->run->system_event.type = type;
 223         vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
 224 }
 225
 226 static void kvm_psci_system_off(struct kvm_vcpu *vcpu)
 227 {
 228         kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
 229 }
 230
 231 static void kvm_psci_system_reset(struct kvm_vcpu *vcpu)
 232 {
 233         kvm_prepare_system_event(vcpu, KVM_SYSTEM_EVENT_RESET);
 234 }
 235
 236 static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
 237 {
 238         struct kvm *kvm = vcpu->kvm;
 239         u32 psci_fn = smccc_get_function(vcpu);
 240         unsigned long val;
 241         int ret = 1;
 242
 243         switch (psci_fn) {
 244         case PSCI_0_2_FN_PSCI_VERSION:
 245                 /*
 246                  * Bits[31:16] = Major Version = 0
 247                  * Bits[15:0] = Minor Version = 2
 248                  */
 249                 val = KVM_ARM_PSCI_0_2;
 250                 break;
 251         case PSCI_0_2_FN_CPU_SUSPEND:
 252         case PSCI_0_2_FN64_CPU_SUSPEND:
 253                 val = kvm_psci_vcpu_suspend(vcpu);
 254                 break;
 255         case PSCI_0_2_FN_CPU_OFF:
 256                 kvm_psci_vcpu_off(vcpu);
 257                 val = PSCI_RET_SUCCESS;
 258                 break;
 259         case PSCI_0_2_FN_CPU_ON:
 260         case PSCI_0_2_FN64_CPU_ON:
 261                 mutex_lock(&kvm->lock);
 262                 val = kvm_psci_vcpu_on(vcpu);
 263                 mutex_unlock(&kvm->lock);
 264                 break;
 265         case PSCI_0_2_FN_AFFINITY_INFO:
 266         case PSCI_0_2_FN64_AFFINITY_INFO:
 267                 val = kvm_psci_vcpu_affinity_info(vcpu);
 268                 break;
 269         case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
 270                 /*
 271                  * Trusted OS is MP hence does not require migration
 272                  * or
 273                  * Trusted OS is not present
 274                  */
 275                 val = PSCI_0_2_TOS_MP;
 276                 break;
 277         case PSCI_0_2_FN_SYSTEM_OFF:
 278                 kvm_psci_system_off(vcpu);
 279                 /*
 280                  * We should'nt be going back to guest VCPU after
 281                  * receiving SYSTEM_OFF request.
 282                  *
 283                  * If user space accidently/deliberately resumes
 284                  * guest VCPU after SYSTEM_OFF request then guest
 285                  * VCPU should see internal failure from PSCI return
 286                  * value. To achieve this, we preload r0 (or x0) with
 287                  * PSCI return value INTERNAL_FAILURE.
 288                  */
 289                 val = PSCI_RET_INTERNAL_FAILURE;
 290                 ret = 0;
 291                 break;
 292         case PSCI_0_2_FN_SYSTEM_RESET:
 293                 kvm_psci_system_reset(vcpu);
 294                 /*
 295                  * Same reason as SYSTEM_OFF for preloading r0 (or x0)
 296                  * with PSCI return value INTERNAL_FAILURE.
 297                  */
 298                 val = PSCI_RET_INTERNAL_FAILURE;
 299                 ret = 0;
 300                 break;
 301         default:
 302                 val = PSCI_RET_NOT_SUPPORTED;
 303                 break;
 304         }
 305
 306         smccc_set_retval(vcpu, val, 0, 0, 0);
 307         return ret;
 308 }
 309
 310 static int kvm_psci_1_0_call(struct kvm_vcpu *vcpu)
 311 {
 312         u32 psci_fn = smccc_get_function(vcpu);
 313         u32 feature;
 314         unsigned long val;
 315         int ret = 1;
 316
 317         switch(psci_fn) {
 318         case PSCI_0_2_FN_PSCI_VERSION:
 319                 val = KVM_ARM_PSCI_1_0;
 320                 break;
 321         case PSCI_1_0_FN_PSCI_FEATURES:
 322                 feature = smccc_get_arg1(vcpu);
 323                 switch(feature) {
 324                 case PSCI_0_2_FN_PSCI_VERSION:
 325                 case PSCI_0_2_FN_CPU_SUSPEND:
 326                 case PSCI_0_2_FN64_CPU_SUSPEND:
 327                 case PSCI_0_2_FN_CPU_OFF:
 328                 case PSCI_0_2_FN_CPU_ON:
 329                 case PSCI_0_2_FN64_CPU_ON:
 330                 case PSCI_0_2_FN_AFFINITY_INFO:
 331                 case PSCI_0_2_FN64_AFFINITY_INFO:
 332                 case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
 333                 case PSCI_0_2_FN_SYSTEM_OFF:
 334                 case PSCI_0_2_FN_SYSTEM_RESET:
 335                 case PSCI_1_0_FN_PSCI_FEATURES:
 336                 case ARM_SMCCC_VERSION_FUNC_ID:
 337                         val = 0;
 338                         break;
 339                 default:
 340                         val = PSCI_RET_NOT_SUPPORTED;
 341                         break;
 342                 }
 343                 break;
 344         default:
 345                 return kvm_psci_0_2_call(vcpu);
 346         }
 347
 348         smccc_set_retval(vcpu, val, 0, 0, 0);
 349         return ret;
 350 }
 351
 352 static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu)
 353 {
 354         struct kvm *kvm = vcpu->kvm;
 355         u32 psci_fn = smccc_get_function(vcpu);
 356         unsigned long val;
 357
 358         switch (psci_fn) {
 359         case KVM_PSCI_FN_CPU_OFF:
 360                 kvm_psci_vcpu_off(vcpu);
 361                 val = PSCI_RET_SUCCESS;
 362                 break;
 363         case KVM_PSCI_FN_CPU_ON:
 364                 mutex_lock(&kvm->lock);
 365                 val = kvm_psci_vcpu_on(vcpu);
 366                 mutex_unlock(&kvm->lock);
 367                 break;
 368         default:
 369                 val = PSCI_RET_NOT_SUPPORTED;
 370                 break;
 371         }
 372
 373         smccc_set_retval(vcpu, val, 0, 0, 0);
 374         return 1;
 375 }
 376
 377 /**
 378  * kvm_psci_call - handle PSCI call if r0 value is in range
 379  * @vcpu: Pointer to the VCPU struct
 380  *
 381  * Handle PSCI calls from guests through traps from HVC instructions.
 382  * The calling convention is similar to SMC calls to the secure world
 383  * where the function number is placed in r0.
 384  *
 385  * This function returns: > 0 (success), 0 (success but exit to user
 386  * space), and < 0 (errors)
 387  *
 388  * Errors:
 389  * -EINVAL: Unrecognized PSCI function
 390  */
 391 static int kvm_psci_call(struct kvm_vcpu *vcpu)
 392 {
 393         switch (kvm_psci_version(vcpu, vcpu->kvm)) {
 394         case KVM_ARM_PSCI_1_0:
 395                 return kvm_psci_1_0_call(vcpu);
 396         case KVM_ARM_PSCI_0_2:
 397                 return kvm_psci_0_2_call(vcpu);
 398         case KVM_ARM_PSCI_0_1:
 399                 return kvm_psci_0_1_call(vcpu);
 400         default:
 401                 return -EINVAL;
 402         };
 403 }
 404
 405 int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 406 {
 407         u32 func_id = smccc_get_function(vcpu);
 408         u32 val = SMCCC_RET_NOT_SUPPORTED;
 409         u32 feature;
 410
 411         switch (func_id) {
 412         case ARM_SMCCC_VERSION_FUNC_ID:
 413                 val = ARM_SMCCC_VERSION_1_1;
 414                 break;
 415         case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
 416                 feature = smccc_get_arg1(vcpu);
 417                 switch(feature) {
 418                 case ARM_SMCCC_ARCH_WORKAROUND_1:
 419                         if (kvm_arm_harden_branch_predictor())
 420                                 val = SMCCC_RET_SUCCESS;
 421                         break;
 422                 case ARM_SMCCC_ARCH_WORKAROUND_2:
 423                         switch (kvm_arm_have_ssbd()) {
 424                         case KVM_SSBD_FORCE_DISABLE:
 425                         case KVM_SSBD_UNKNOWN:
 426                                 break;
 427                         case KVM_SSBD_KERNEL:
 428                                 val = SMCCC_RET_SUCCESS;
 429                                 break;
 430                         case KVM_SSBD_FORCE_ENABLE:
 431                         case KVM_SSBD_MITIGATED:
 432                                 val = SMCCC_RET_NOT_REQUIRED;
 433                                 break;
 434                         }
 435                         break;
 436                 }
 437                 break;
 438         default:
 439                 return kvm_psci_call(vcpu);
 440         }
 441
 442         smccc_set_retval(vcpu, val, 0, 0, 0);
 443         return 1;
 444 }
 445
 446 int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
 447 {
 448         return 1;               /* PSCI version */
 449 }
 450
 451 int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
 452 {
 453         if (put_user(KVM_REG_ARM_PSCI_VERSION, uindices))
 454                 return -EFAULT;
 455
 456         return 0;
 457 }
 458
 459 int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 460 {
 461         if (reg->id == KVM_REG_ARM_PSCI_VERSION) {
 462                 void __user *uaddr = (void __user *)(long)reg->addr;
 463                 u64 val;
 464
 465                 val = kvm_psci_version(vcpu, vcpu->kvm);
 466                 if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
 467                         return -EFAULT;
 468
 469                 return 0;
 470         }
 471
 472         return -EINVAL;
 473 }
 474
 475 int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 476 {
 477         if (reg->id == KVM_REG_ARM_PSCI_VERSION) {
 478                 void __user *uaddr = (void __user *)(long)reg->addr;
 479                 bool wants_02;
 480                 u64 val;
 481
 482                 if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
 483                         return -EFAULT;
 484
 485                 wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features);
 486
 487                 switch (val) {
 488                 case KVM_ARM_PSCI_0_1:
 489                         if (wants_02)
 490                                 return -EINVAL;
 491                         vcpu->kvm->arch.psci_version = val;
 492                         return 0;
 493                 case KVM_ARM_PSCI_0_2:
 494                 case KVM_ARM_PSCI_1_0:
 495                         if (!wants_02)
 496                                 return -EINVAL;
 497                         vcpu->kvm->arch.psci_version = val;
 498                         return 0;
 499                 }
 500         }
 501
 502         return -EINVAL;
 503 }