arch/x86/kvm/xen.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright © 2019 Oracle and/or its affiliates. All rights reserved.
   4  * Copyright © 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   5  *
   6  * KVM Xen emulation
   7  */
   8
   9 #include "x86.h"
  10 #include "xen.h"
  11 #include "hyperv.h"
  12
  13 #include <linux/kvm_host.h>
  14 #include <linux/sched/stat.h>
  15
  16 #include <trace/events/kvm.h>
  17 #include <xen/interface/xen.h>
  18 #include <xen/interface/vcpu.h>
  19
  20 #include "trace.h"
  21
  22 DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ);
  23
  24 static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
  25 {
  26         gpa_t gpa = gfn_to_gpa(gfn);
  27         int wc_ofs, sec_hi_ofs;
  28         int ret = 0;
  29         int idx = srcu_read_lock(&kvm->srcu);
  30
  31         if (kvm_is_error_hva(gfn_to_hva(kvm, gfn))) {
  32                 ret = -EFAULT;
  33                 goto out;
  34         }
  35         kvm->arch.xen.shinfo_gfn = gfn;
  36
  37         /* Paranoia checks on the 32-bit struct layout */
  38         BUILD_BUG_ON(offsetof(struct compat_shared_info, wc) != 0x900);
  39         BUILD_BUG_ON(offsetof(struct compat_shared_info, arch.wc_sec_hi) != 0x924);
  40         BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0);
  41
  42         /* 32-bit location by default */
  43         wc_ofs = offsetof(struct compat_shared_info, wc);
  44         sec_hi_ofs = offsetof(struct compat_shared_info, arch.wc_sec_hi);
  45
  46 #ifdef CONFIG_X86_64
  47         /* Paranoia checks on the 64-bit struct layout */
  48         BUILD_BUG_ON(offsetof(struct shared_info, wc) != 0xc00);
  49         BUILD_BUG_ON(offsetof(struct shared_info, wc_sec_hi) != 0xc0c);
  50
  51         if (kvm->arch.xen.long_mode) {
  52                 wc_ofs = offsetof(struct shared_info, wc);
  53                 sec_hi_ofs = offsetof(struct shared_info, wc_sec_hi);
  54         }
  55 #endif
  56
  57         kvm_write_wall_clock(kvm, gpa + wc_ofs, sec_hi_ofs - wc_ofs);
  58         kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE);
  59
  60 out:
  61         srcu_read_unlock(&kvm->srcu, idx);
  62         return ret;
  63 }
  64
  65 static void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
  66 {
  67         struct kvm_vcpu_xen *vx = &v->arch.xen;
  68         u64 now = get_kvmclock_ns(v->kvm);
  69         u64 delta_ns = now - vx->runstate_entry_time;
  70         u64 run_delay = current->sched_info.run_delay;
  71
  72         if (unlikely(!vx->runstate_entry_time))
  73                 vx->current_runstate = RUNSTATE_offline;
  74
  75         /*
  76          * Time waiting for the scheduler isn't "stolen" if the
  77          * vCPU wasn't running anyway.
  78          */
  79         if (vx->current_runstate == RUNSTATE_running) {
  80                 u64 steal_ns = run_delay - vx->last_steal;
  81
  82                 delta_ns -= steal_ns;
  83
  84                 vx->runstate_times[RUNSTATE_runnable] += steal_ns;
  85         }
  86         vx->last_steal = run_delay;
  87
  88         vx->runstate_times[vx->current_runstate] += delta_ns;
  89         vx->current_runstate = state;
  90         vx->runstate_entry_time = now;
  91 }
  92
  93 void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state)
  94 {
  95         struct kvm_vcpu_xen *vx = &v->arch.xen;
  96         uint64_t state_entry_time;
  97         unsigned int offset;
  98
  99         kvm_xen_update_runstate(v, state);
 100
 101         if (!vx->runstate_set)
 102                 return;
 103
 104         BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c);
 105
 106         offset = offsetof(struct compat_vcpu_runstate_info, state_entry_time);
 107 #ifdef CONFIG_X86_64
 108         /*
 109          * The only difference is alignment of uint64_t in 32-bit.
 110          * So the first field 'state' is accessed directly using
 111          * offsetof() (where its offset happens to be zero), while the
 112          * remaining fields which are all uint64_t, start at 'offset'
 113          * which we tweak here by adding 4.
 114          */
 115         BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
 116                      offsetof(struct compat_vcpu_runstate_info, state_entry_time) + 4);
 117         BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, time) !=
 118                      offsetof(struct compat_vcpu_runstate_info, time) + 4);
 119
 120         if (v->kvm->arch.xen.long_mode)
 121                 offset = offsetof(struct vcpu_runstate_info, state_entry_time);
 122 #endif
 123         /*
 124          * First write the updated state_entry_time at the appropriate
 125          * location determined by 'offset'.
 126          */
 127         state_entry_time = vx->runstate_entry_time;
 128         state_entry_time |= XEN_RUNSTATE_UPDATE;
 129
 130         BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state_entry_time) !=
 131                      sizeof(state_entry_time));
 132         BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) !=
 133                      sizeof(state_entry_time));
 134
 135         if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache,
 136                                           &state_entry_time, offset,
 137                                           sizeof(state_entry_time)))
 138                 return;
 139         smp_wmb();
 140
 141         /*
 142          * Next, write the new runstate. This is in the *same* place
 143          * for 32-bit and 64-bit guests, asserted here for paranoia.
 144          */
 145         BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) !=
 146                      offsetof(struct compat_vcpu_runstate_info, state));
 147         BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state) !=
 148                      sizeof(vx->current_runstate));
 149         BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state) !=
 150                      sizeof(vx->current_runstate));
 151
 152         if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache,
 153                                           &vx->current_runstate,
 154                                           offsetof(struct vcpu_runstate_info, state),
 155                                           sizeof(vx->current_runstate)))
 156                 return;
 157
 158         /*
 159          * Write the actual runstate times immediately after the
 160          * runstate_entry_time.
 161          */
 162         BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
 163                      offsetof(struct vcpu_runstate_info, time) - sizeof(u64));
 164         BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state_entry_time) !=
 165                      offsetof(struct compat_vcpu_runstate_info, time) - sizeof(u64));
 166         BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
 167                      sizeof_field(struct compat_vcpu_runstate_info, time));
 168         BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
 169                      sizeof(vx->runstate_times));
 170
 171         if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache,
 172                                           &vx->runstate_times[0],
 173                                           offset + sizeof(u64),
 174                                           sizeof(vx->runstate_times)))
 175                 return;
 176
 177         smp_wmb();
 178
 179         /*
 180          * Finally, clear the XEN_RUNSTATE_UPDATE bit in the guest's
 181          * runstate_entry_time field.
 182          */
 183
 184         state_entry_time &= ~XEN_RUNSTATE_UPDATE;
 185         if (kvm_write_guest_offset_cached(v->kvm, &v->arch.xen.runstate_cache,
 186                                           &state_entry_time, offset,
 187                                           sizeof(state_entry_time)))
 188                 return;
 189 }
 190
 191 int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
 192 {
 193         int err;
 194         u8 rc = 0;
 195
 196         /*
 197          * If the global upcall vector (HVMIRQ_callback_vector) is set and
 198          * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending.
 199          */
 200         struct gfn_to_hva_cache *ghc = &v->arch.xen.vcpu_info_cache;
 201         struct kvm_memslots *slots = kvm_memslots(v->kvm);
 202         unsigned int offset = offsetof(struct vcpu_info, evtchn_upcall_pending);
 203
 204         /* No need for compat handling here */
 205         BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) !=
 206                      offsetof(struct compat_vcpu_info, evtchn_upcall_pending));
 207         BUILD_BUG_ON(sizeof(rc) !=
 208                      sizeof_field(struct vcpu_info, evtchn_upcall_pending));
 209         BUILD_BUG_ON(sizeof(rc) !=
 210                      sizeof_field(struct compat_vcpu_info, evtchn_upcall_pending));
 211
 212         /*
 213          * For efficiency, this mirrors the checks for using the valid
 214          * cache in kvm_read_guest_offset_cached(), but just uses
 215          * __get_user() instead. And falls back to the slow path.
 216          */
 217         if (likely(slots->generation == ghc->generation &&
 218                    !kvm_is_error_hva(ghc->hva) && ghc->memslot)) {
 219                 /* Fast path */
 220                 pagefault_disable();
 221                 err = __get_user(rc, (u8 __user *)ghc->hva + offset);
 222                 pagefault_enable();
 223                 if (!err)
 224                         return rc;
 225         }
 226
 227         /* Slow path */
 228
 229         /*
 230          * This function gets called from kvm_vcpu_block() after setting the
 231          * task to TASK_INTERRUPTIBLE, to see if it needs to wake immediately
 232          * from a HLT. So we really mustn't sleep. If the page ended up absent
 233          * at that point, just return 1 in order to trigger an immediate wake,
 234          * and we'll end up getting called again from a context where we *can*
 235          * fault in the page and wait for it.
 236          */
 237         if (in_atomic() || !task_is_running(current))
 238                 return 1;
 239
 240         kvm_read_guest_offset_cached(v->kvm, ghc, &rc, offset,
 241                                      sizeof(rc));
 242
 243         return rc;
 244 }
 245
 246 int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 247 {
 248         int r = -ENOENT;
 249
 250         mutex_lock(&kvm->lock);
 251
 252         switch (data->type) {
 253         case KVM_XEN_ATTR_TYPE_LONG_MODE:
 254                 if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) {
 255                         r = -EINVAL;
 256                 } else {
 257                         kvm->arch.xen.long_mode = !!data->u.long_mode;
 258                         r = 0;
 259                 }
 260                 break;
 261
 262         case KVM_XEN_ATTR_TYPE_SHARED_INFO:
 263                 if (data->u.shared_info.gfn == GPA_INVALID) {
 264                         kvm->arch.xen.shinfo_gfn = GPA_INVALID;
 265                         r = 0;
 266                         break;
 267                 }
 268                 r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
 269                 break;
 270
 271
 272         case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
 273                 if (data->u.vector && data->u.vector < 0x10)
 274                         r = -EINVAL;
 275                 else {
 276                         kvm->arch.xen.upcall_vector = data->u.vector;
 277                         r = 0;
 278                 }
 279                 break;
 280
 281         default:
 282                 break;
 283         }
 284
 285         mutex_unlock(&kvm->lock);
 286         return r;
 287 }
 288
 289 int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 290 {
 291         int r = -ENOENT;
 292
 293         mutex_lock(&kvm->lock);
 294
 295         switch (data->type) {
 296         case KVM_XEN_ATTR_TYPE_LONG_MODE:
 297                 data->u.long_mode = kvm->arch.xen.long_mode;
 298                 r = 0;
 299                 break;
 300
 301         case KVM_XEN_ATTR_TYPE_SHARED_INFO:
 302                 data->u.shared_info.gfn = kvm->arch.xen.shinfo_gfn;
 303                 r = 0;
 304                 break;
 305
 306         case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
 307                 data->u.vector = kvm->arch.xen.upcall_vector;
 308                 r = 0;
 309                 break;
 310
 311         default:
 312                 break;
 313         }
 314
 315         mutex_unlock(&kvm->lock);
 316         return r;
 317 }
 318
 319 int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 320 {
 321         int idx, r = -ENOENT;
 322
 323         mutex_lock(&vcpu->kvm->lock);
 324         idx = srcu_read_lock(&vcpu->kvm->srcu);
 325
 326         switch (data->type) {
 327         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
 328                 /* No compat necessary here. */
 329                 BUILD_BUG_ON(sizeof(struct vcpu_info) !=
 330                              sizeof(struct compat_vcpu_info));
 331                 BUILD_BUG_ON(offsetof(struct vcpu_info, time) !=
 332                              offsetof(struct compat_vcpu_info, time));
 333
 334                 if (data->u.gpa == GPA_INVALID) {
 335                         vcpu->arch.xen.vcpu_info_set = false;
 336                         r = 0;
 337                         break;
 338                 }
 339
 340                 r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
 341                                               &vcpu->arch.xen.vcpu_info_cache,
 342                                               data->u.gpa,
 343                                               sizeof(struct vcpu_info));
 344                 if (!r) {
 345                         vcpu->arch.xen.vcpu_info_set = true;
 346                         kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 347                 }
 348                 break;
 349
 350         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 351                 if (data->u.gpa == GPA_INVALID) {
 352                         vcpu->arch.xen.vcpu_time_info_set = false;
 353                         r = 0;
 354                         break;
 355                 }
 356
 357                 r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
 358                                               &vcpu->arch.xen.vcpu_time_info_cache,
 359                                               data->u.gpa,
 360                                               sizeof(struct pvclock_vcpu_time_info));
 361                 if (!r) {
 362                         vcpu->arch.xen.vcpu_time_info_set = true;
 363                         kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 364                 }
 365                 break;
 366
 367         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
 368                 if (!sched_info_on()) {
 369                         r = -EOPNOTSUPP;
 370                         break;
 371                 }
 372                 if (data->u.gpa == GPA_INVALID) {
 373                         vcpu->arch.xen.runstate_set = false;
 374                         r = 0;
 375                         break;
 376                 }
 377
 378                 r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
 379                                               &vcpu->arch.xen.runstate_cache,
 380                                               data->u.gpa,
 381                                               sizeof(struct vcpu_runstate_info));
 382                 if (!r) {
 383                         vcpu->arch.xen.runstate_set = true;
 384                 }
 385                 break;
 386
 387         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
 388                 if (!sched_info_on()) {
 389                         r = -EOPNOTSUPP;
 390                         break;
 391                 }
 392                 if (data->u.runstate.state > RUNSTATE_offline) {
 393                         r = -EINVAL;
 394                         break;
 395                 }
 396
 397                 kvm_xen_update_runstate(vcpu, data->u.runstate.state);
 398                 r = 0;
 399                 break;
 400
 401         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
 402                 if (!sched_info_on()) {
 403                         r = -EOPNOTSUPP;
 404                         break;
 405                 }
 406                 if (data->u.runstate.state > RUNSTATE_offline) {
 407                         r = -EINVAL;
 408                         break;
 409                 }
 410                 if (data->u.runstate.state_entry_time !=
 411                     (data->u.runstate.time_running +
 412                      data->u.runstate.time_runnable +
 413                      data->u.runstate.time_blocked +
 414                      data->u.runstate.time_offline)) {
 415                         r = -EINVAL;
 416                         break;
 417                 }
 418                 if (get_kvmclock_ns(vcpu->kvm) <
 419                     data->u.runstate.state_entry_time) {
 420                         r = -EINVAL;
 421                         break;
 422                 }
 423
 424                 vcpu->arch.xen.current_runstate = data->u.runstate.state;
 425                 vcpu->arch.xen.runstate_entry_time =
 426                         data->u.runstate.state_entry_time;
 427                 vcpu->arch.xen.runstate_times[RUNSTATE_running] =
 428                         data->u.runstate.time_running;
 429                 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] =
 430                         data->u.runstate.time_runnable;
 431                 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] =
 432                         data->u.runstate.time_blocked;
 433                 vcpu->arch.xen.runstate_times[RUNSTATE_offline] =
 434                         data->u.runstate.time_offline;
 435                 vcpu->arch.xen.last_steal = current->sched_info.run_delay;
 436                 r = 0;
 437                 break;
 438
 439         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
 440                 if (!sched_info_on()) {
 441                         r = -EOPNOTSUPP;
 442                         break;
 443                 }
 444                 if (data->u.runstate.state > RUNSTATE_offline &&
 445                     data->u.runstate.state != (u64)-1) {
 446                         r = -EINVAL;
 447                         break;
 448                 }
 449                 /* The adjustment must add up */
 450                 if (data->u.runstate.state_entry_time !=
 451                     (data->u.runstate.time_running +
 452                      data->u.runstate.time_runnable +
 453                      data->u.runstate.time_blocked +
 454                      data->u.runstate.time_offline)) {
 455                         r = -EINVAL;
 456                         break;
 457                 }
 458
 459                 if (get_kvmclock_ns(vcpu->kvm) <
 460                     (vcpu->arch.xen.runstate_entry_time +
 461                      data->u.runstate.state_entry_time)) {
 462                         r = -EINVAL;
 463                         break;
 464                 }
 465
 466                 vcpu->arch.xen.runstate_entry_time +=
 467                         data->u.runstate.state_entry_time;
 468                 vcpu->arch.xen.runstate_times[RUNSTATE_running] +=
 469                         data->u.runstate.time_running;
 470                 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] +=
 471                         data->u.runstate.time_runnable;
 472                 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] +=
 473                         data->u.runstate.time_blocked;
 474                 vcpu->arch.xen.runstate_times[RUNSTATE_offline] +=
 475                         data->u.runstate.time_offline;
 476
 477                 if (data->u.runstate.state <= RUNSTATE_offline)
 478                         kvm_xen_update_runstate(vcpu, data->u.runstate.state);
 479                 r = 0;
 480                 break;
 481
 482         default:
 483                 break;
 484         }
 485
 486         srcu_read_unlock(&vcpu->kvm->srcu, idx);
 487         mutex_unlock(&vcpu->kvm->lock);
 488         return r;
 489 }
 490
 491 int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 492 {
 493         int r = -ENOENT;
 494
 495         mutex_lock(&vcpu->kvm->lock);
 496
 497         switch (data->type) {
 498         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
 499                 if (vcpu->arch.xen.vcpu_info_set)
 500                         data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
 501                 else
 502                         data->u.gpa = GPA_INVALID;
 503                 r = 0;
 504                 break;
 505
 506         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 507                 if (vcpu->arch.xen.vcpu_time_info_set)
 508                         data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
 509                 else
 510                         data->u.gpa = GPA_INVALID;
 511                 r = 0;
 512                 break;
 513
 514         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
 515                 if (!sched_info_on()) {
 516                         r = -EOPNOTSUPP;
 517                         break;
 518                 }
 519                 if (vcpu->arch.xen.runstate_set) {
 520                         data->u.gpa = vcpu->arch.xen.runstate_cache.gpa;
 521                         r = 0;
 522                 }
 523                 break;
 524
 525         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
 526                 if (!sched_info_on()) {
 527                         r = -EOPNOTSUPP;
 528                         break;
 529                 }
 530                 data->u.runstate.state = vcpu->arch.xen.current_runstate;
 531                 r = 0;
 532                 break;
 533
 534         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
 535                 if (!sched_info_on()) {
 536                         r = -EOPNOTSUPP;
 537                         break;
 538                 }
 539                 data->u.runstate.state = vcpu->arch.xen.current_runstate;
 540                 data->u.runstate.state_entry_time =
 541                         vcpu->arch.xen.runstate_entry_time;
 542                 data->u.runstate.time_running =
 543                         vcpu->arch.xen.runstate_times[RUNSTATE_running];
 544                 data->u.runstate.time_runnable =
 545                         vcpu->arch.xen.runstate_times[RUNSTATE_runnable];
 546                 data->u.runstate.time_blocked =
 547                         vcpu->arch.xen.runstate_times[RUNSTATE_blocked];
 548                 data->u.runstate.time_offline =
 549                         vcpu->arch.xen.runstate_times[RUNSTATE_offline];
 550                 r = 0;
 551                 break;
 552
 553         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
 554                 r = -EINVAL;
 555                 break;
 556
 557         default:
 558                 break;
 559         }
 560
 561         mutex_unlock(&vcpu->kvm->lock);
 562         return r;
 563 }
 564
 565 int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
 566 {
 567         struct kvm *kvm = vcpu->kvm;
 568         u32 page_num = data & ~PAGE_MASK;
 569         u64 page_addr = data & PAGE_MASK;
 570         bool lm = is_long_mode(vcpu);
 571
 572         /* Latch long_mode for shared_info pages etc. */
 573         vcpu->kvm->arch.xen.long_mode = lm;
 574
 575         /*
 576          * If Xen hypercall intercept is enabled, fill the hypercall
 577          * page with VMCALL/VMMCALL instructions since that's what
 578          * we catch. Else the VMM has provided the hypercall pages
 579          * with instructions of its own choosing, so use those.
 580          */
 581         if (kvm_xen_hypercall_enabled(kvm)) {
 582                 u8 instructions[32];
 583                 int i;
 584
 585                 if (page_num)
 586                         return 1;
 587
 588                 /* mov imm32, %eax */
 589                 instructions[0] = 0xb8;
 590
 591                 /* vmcall / vmmcall */
 592                 kvm_x86_ops.patch_hypercall(vcpu, instructions + 5);
 593
 594                 /* ret */
 595                 instructions[8] = 0xc3;
 596
 597                 /* int3 to pad */
 598                 memset(instructions + 9, 0xcc, sizeof(instructions) - 9);
 599
 600                 for (i = 0; i < PAGE_SIZE / sizeof(instructions); i++) {
 601                         *(u32 *)&instructions[1] = i;
 602                         if (kvm_vcpu_write_guest(vcpu,
 603                                                  page_addr + (i * sizeof(instructions)),
 604                                                  instructions, sizeof(instructions)))
 605                                 return 1;
 606                 }
 607         } else {
 608                 /*
 609                  * Note, truncation is a non-issue as 'lm' is guaranteed to be
 610                  * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes.
 611                  */
 612                 hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64
 613                                      : kvm->arch.xen_hvm_config.blob_addr_32;
 614                 u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
 615                                   : kvm->arch.xen_hvm_config.blob_size_32;
 616                 u8 *page;
 617
 618                 if (page_num >= blob_size)
 619                         return 1;
 620
 621                 blob_addr += page_num * PAGE_SIZE;
 622
 623                 page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE);
 624                 if (IS_ERR(page))
 625                         return PTR_ERR(page);
 626
 627                 if (kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE)) {
 628                         kfree(page);
 629                         return 1;
 630                 }
 631         }
 632         return 0;
 633 }
 634
 635 int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
 636 {
 637         if (xhc->flags & ~KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL)
 638                 return -EINVAL;
 639
 640         /*
 641          * With hypercall interception the kernel generates its own
 642          * hypercall page so it must not be provided.
 643          */
 644         if ((xhc->flags & KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) &&
 645             (xhc->blob_addr_32 || xhc->blob_addr_64 ||
 646              xhc->blob_size_32 || xhc->blob_size_64))
 647                 return -EINVAL;
 648
 649         mutex_lock(&kvm->lock);
 650
 651         if (xhc->msr && !kvm->arch.xen_hvm_config.msr)
 652                 static_branch_inc(&kvm_xen_enabled.key);
 653         else if (!xhc->msr && kvm->arch.xen_hvm_config.msr)
 654                 static_branch_slow_dec_deferred(&kvm_xen_enabled);
 655
 656         memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc));
 657
 658         mutex_unlock(&kvm->lock);
 659         return 0;
 660 }
 661
 662 void kvm_xen_init_vm(struct kvm *kvm)
 663 {
 664         kvm->arch.xen.shinfo_gfn = GPA_INVALID;
 665 }
 666
 667 void kvm_xen_destroy_vm(struct kvm *kvm)
 668 {
 669         if (kvm->arch.xen_hvm_config.msr)
 670                 static_branch_slow_dec_deferred(&kvm_xen_enabled);
 671 }
 672
 673 static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
 674 {
 675         kvm_rax_write(vcpu, result);
 676         return kvm_skip_emulated_instruction(vcpu);
 677 }
 678
 679 static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
 680 {
 681         struct kvm_run *run = vcpu->run;
 682
 683         if (unlikely(!kvm_is_linear_rip(vcpu, vcpu->arch.xen.hypercall_rip)))
 684                 return 1;
 685
 686         return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result);
 687 }
 688
 689 int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
 690 {
 691         bool longmode;
 692         u64 input, params[6];
 693
 694         input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);
 695
 696         /* Hyper-V hypercalls get bit 31 set in EAX */
 697         if ((input & 0x80000000) &&
 698             kvm_hv_hypercall_enabled(vcpu))
 699                 return kvm_hv_hypercall(vcpu);
 700
 701         longmode = is_64_bit_hypercall(vcpu);
 702         if (!longmode) {
 703                 params[0] = (u32)kvm_rbx_read(vcpu);
 704                 params[1] = (u32)kvm_rcx_read(vcpu);
 705                 params[2] = (u32)kvm_rdx_read(vcpu);
 706                 params[3] = (u32)kvm_rsi_read(vcpu);
 707                 params[4] = (u32)kvm_rdi_read(vcpu);
 708                 params[5] = (u32)kvm_rbp_read(vcpu);
 709         }
 710 #ifdef CONFIG_X86_64
 711         else {
 712                 params[0] = (u64)kvm_rdi_read(vcpu);
 713                 params[1] = (u64)kvm_rsi_read(vcpu);
 714                 params[2] = (u64)kvm_rdx_read(vcpu);
 715                 params[3] = (u64)kvm_r10_read(vcpu);
 716                 params[4] = (u64)kvm_r8_read(vcpu);
 717                 params[5] = (u64)kvm_r9_read(vcpu);
 718         }
 719 #endif
 720         trace_kvm_xen_hypercall(input, params[0], params[1], params[2],
 721                                 params[3], params[4], params[5]);
 722
 723         vcpu->run->exit_reason = KVM_EXIT_XEN;
 724         vcpu->run->xen.type = KVM_EXIT_XEN_HCALL;
 725         vcpu->run->xen.u.hcall.longmode = longmode;
 726         vcpu->run->xen.u.hcall.cpl = kvm_x86_ops.get_cpl(vcpu);
 727         vcpu->run->xen.u.hcall.input = input;
 728         vcpu->run->xen.u.hcall.params[0] = params[0];
 729         vcpu->run->xen.u.hcall.params[1] = params[1];
 730         vcpu->run->xen.u.hcall.params[2] = params[2];
 731         vcpu->run->xen.u.hcall.params[3] = params[3];
 732         vcpu->run->xen.u.hcall.params[4] = params[4];
 733         vcpu->run->xen.u.hcall.params[5] = params[5];
 734         vcpu->arch.xen.hypercall_rip = kvm_get_linear_rip(vcpu);
 735         vcpu->arch.complete_userspace_io =
 736                 kvm_xen_hypercall_complete_userspace;
 737
 738         return 0;
 739 }