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(((struct vcpu_runstate_info *)0)->state_entry_time) !=
 131                      sizeof(state_entry_time));
 132         BUILD_BUG_ON(sizeof(((struct compat_vcpu_runstate_info *)0)->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(((struct vcpu_runstate_info *)0)->state) !=
 148                      sizeof(vx->current_runstate));
 149         BUILD_BUG_ON(sizeof(((struct compat_vcpu_runstate_info *)0)->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(((struct vcpu_runstate_info *)0)->time) !=
 167                      sizeof(((struct compat_vcpu_runstate_info *)0)->time));
 168         BUILD_BUG_ON(sizeof(((struct vcpu_runstate_info *)0)->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         u8 rc = 0;
 194
 195         /*
 196          * If the global upcall vector (HVMIRQ_callback_vector) is set and
 197          * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending.
 198          */
 199         struct gfn_to_hva_cache *ghc = &v->arch.xen.vcpu_info_cache;
 200         struct kvm_memslots *slots = kvm_memslots(v->kvm);
 201         unsigned int offset = offsetof(struct vcpu_info, evtchn_upcall_pending);
 202
 203         /* No need for compat handling here */
 204         BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) !=
 205                      offsetof(struct compat_vcpu_info, evtchn_upcall_pending));
 206         BUILD_BUG_ON(sizeof(rc) !=
 207                      sizeof(((struct vcpu_info *)0)->evtchn_upcall_pending));
 208         BUILD_BUG_ON(sizeof(rc) !=
 209                      sizeof(((struct compat_vcpu_info *)0)->evtchn_upcall_pending));
 210
 211         /*
 212          * For efficiency, this mirrors the checks for using the valid
 213          * cache in kvm_read_guest_offset_cached(), but just uses
 214          * __get_user() instead. And falls back to the slow path.
 215          */
 216         if (likely(slots->generation == ghc->generation &&
 217                    !kvm_is_error_hva(ghc->hva) && ghc->memslot)) {
 218                 /* Fast path */
 219                 __get_user(rc, (u8 __user *)ghc->hva + offset);
 220         } else {
 221                 /* Slow path */
 222                 kvm_read_guest_offset_cached(v->kvm, ghc, &rc, offset,
 223                                              sizeof(rc));
 224         }
 225
 226         return rc;
 227 }
 228
 229 int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 230 {
 231         int r = -ENOENT;
 232
 233         mutex_lock(&kvm->lock);
 234
 235         switch (data->type) {
 236         case KVM_XEN_ATTR_TYPE_LONG_MODE:
 237                 if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) {
 238                         r = -EINVAL;
 239                 } else {
 240                         kvm->arch.xen.long_mode = !!data->u.long_mode;
 241                         r = 0;
 242                 }
 243                 break;
 244
 245         case KVM_XEN_ATTR_TYPE_SHARED_INFO:
 246                 if (data->u.shared_info.gfn == GPA_INVALID) {
 247                         kvm->arch.xen.shinfo_gfn = GPA_INVALID;
 248                         r = 0;
 249                         break;
 250                 }
 251                 r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
 252                 break;
 253
 254
 255         case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
 256                 if (data->u.vector && data->u.vector < 0x10)
 257                         r = -EINVAL;
 258                 else {
 259                         kvm->arch.xen.upcall_vector = data->u.vector;
 260                         r = 0;
 261                 }
 262                 break;
 263
 264         default:
 265                 break;
 266         }
 267
 268         mutex_unlock(&kvm->lock);
 269         return r;
 270 }
 271
 272 int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 273 {
 274         int r = -ENOENT;
 275
 276         mutex_lock(&kvm->lock);
 277
 278         switch (data->type) {
 279         case KVM_XEN_ATTR_TYPE_LONG_MODE:
 280                 data->u.long_mode = kvm->arch.xen.long_mode;
 281                 r = 0;
 282                 break;
 283
 284         case KVM_XEN_ATTR_TYPE_SHARED_INFO:
 285                 data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_gfn);
 286                 r = 0;
 287                 break;
 288
 289         case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
 290                 data->u.vector = kvm->arch.xen.upcall_vector;
 291                 r = 0;
 292                 break;
 293
 294         default:
 295                 break;
 296         }
 297
 298         mutex_unlock(&kvm->lock);
 299         return r;
 300 }
 301
 302 int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 303 {
 304         int idx, r = -ENOENT;
 305
 306         mutex_lock(&vcpu->kvm->lock);
 307         idx = srcu_read_lock(&vcpu->kvm->srcu);
 308
 309         switch (data->type) {
 310         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
 311                 /* No compat necessary here. */
 312                 BUILD_BUG_ON(sizeof(struct vcpu_info) !=
 313                              sizeof(struct compat_vcpu_info));
 314                 BUILD_BUG_ON(offsetof(struct vcpu_info, time) !=
 315                              offsetof(struct compat_vcpu_info, time));
 316
 317                 if (data->u.gpa == GPA_INVALID) {
 318                         vcpu->arch.xen.vcpu_info_set = false;
 319                         r = 0;
 320                         break;
 321                 }
 322
 323                 r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
 324                                               &vcpu->arch.xen.vcpu_info_cache,
 325                                               data->u.gpa,
 326                                               sizeof(struct vcpu_info));
 327                 if (!r) {
 328                         vcpu->arch.xen.vcpu_info_set = true;
 329                         kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 330                 }
 331                 break;
 332
 333         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 334                 if (data->u.gpa == GPA_INVALID) {
 335                         vcpu->arch.xen.vcpu_time_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_time_info_cache,
 342                                               data->u.gpa,
 343                                               sizeof(struct pvclock_vcpu_time_info));
 344                 if (!r) {
 345                         vcpu->arch.xen.vcpu_time_info_set = true;
 346                         kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 347                 }
 348                 break;
 349
 350         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
 351                 if (!sched_info_on()) {
 352                         r = -EOPNOTSUPP;
 353                         break;
 354                 }
 355                 if (data->u.gpa == GPA_INVALID) {
 356                         vcpu->arch.xen.runstate_set = false;
 357                         r = 0;
 358                         break;
 359                 }
 360
 361                 r = kvm_gfn_to_hva_cache_init(vcpu->kvm,
 362                                               &vcpu->arch.xen.runstate_cache,
 363                                               data->u.gpa,
 364                                               sizeof(struct vcpu_runstate_info));
 365                 if (!r) {
 366                         vcpu->arch.xen.runstate_set = true;
 367                 }
 368                 break;
 369
 370         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
 371                 if (!sched_info_on()) {
 372                         r = -EOPNOTSUPP;
 373                         break;
 374                 }
 375                 if (data->u.runstate.state > RUNSTATE_offline) {
 376                         r = -EINVAL;
 377                         break;
 378                 }
 379
 380                 kvm_xen_update_runstate(vcpu, data->u.runstate.state);
 381                 r = 0;
 382                 break;
 383
 384         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
 385                 if (!sched_info_on()) {
 386                         r = -EOPNOTSUPP;
 387                         break;
 388                 }
 389                 if (data->u.runstate.state > RUNSTATE_offline) {
 390                         r = -EINVAL;
 391                         break;
 392                 }
 393                 if (data->u.runstate.state_entry_time !=
 394                     (data->u.runstate.time_running +
 395                      data->u.runstate.time_runnable +
 396                      data->u.runstate.time_blocked +
 397                      data->u.runstate.time_offline)) {
 398                         r = -EINVAL;
 399                         break;
 400                 }
 401                 if (get_kvmclock_ns(vcpu->kvm) <
 402                     data->u.runstate.state_entry_time) {
 403                         r = -EINVAL;
 404                         break;
 405                 }
 406
 407                 vcpu->arch.xen.current_runstate = data->u.runstate.state;
 408                 vcpu->arch.xen.runstate_entry_time =
 409                         data->u.runstate.state_entry_time;
 410                 vcpu->arch.xen.runstate_times[RUNSTATE_running] =
 411                         data->u.runstate.time_running;
 412                 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] =
 413                         data->u.runstate.time_runnable;
 414                 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] =
 415                         data->u.runstate.time_blocked;
 416                 vcpu->arch.xen.runstate_times[RUNSTATE_offline] =
 417                         data->u.runstate.time_offline;
 418                 vcpu->arch.xen.last_steal = current->sched_info.run_delay;
 419                 r = 0;
 420                 break;
 421
 422         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
 423                 if (!sched_info_on()) {
 424                         r = -EOPNOTSUPP;
 425                         break;
 426                 }
 427                 if (data->u.runstate.state > RUNSTATE_offline &&
 428                     data->u.runstate.state != (u64)-1) {
 429                         r = -EINVAL;
 430                         break;
 431                 }
 432                 /* The adjustment must add up */
 433                 if (data->u.runstate.state_entry_time !=
 434                     (data->u.runstate.time_running +
 435                      data->u.runstate.time_runnable +
 436                      data->u.runstate.time_blocked +
 437                      data->u.runstate.time_offline)) {
 438                         r = -EINVAL;
 439                         break;
 440                 }
 441
 442                 if (get_kvmclock_ns(vcpu->kvm) <
 443                     (vcpu->arch.xen.runstate_entry_time +
 444                      data->u.runstate.state_entry_time)) {
 445                         r = -EINVAL;
 446                         break;
 447                 }
 448
 449                 vcpu->arch.xen.runstate_entry_time +=
 450                         data->u.runstate.state_entry_time;
 451                 vcpu->arch.xen.runstate_times[RUNSTATE_running] +=
 452                         data->u.runstate.time_running;
 453                 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] +=
 454                         data->u.runstate.time_runnable;
 455                 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] +=
 456                         data->u.runstate.time_blocked;
 457                 vcpu->arch.xen.runstate_times[RUNSTATE_offline] +=
 458                         data->u.runstate.time_offline;
 459
 460                 if (data->u.runstate.state <= RUNSTATE_offline)
 461                         kvm_xen_update_runstate(vcpu, data->u.runstate.state);
 462                 r = 0;
 463                 break;
 464
 465         default:
 466                 break;
 467         }
 468
 469         srcu_read_unlock(&vcpu->kvm->srcu, idx);
 470         mutex_unlock(&vcpu->kvm->lock);
 471         return r;
 472 }
 473
 474 int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 475 {
 476         int r = -ENOENT;
 477
 478         mutex_lock(&vcpu->kvm->lock);
 479
 480         switch (data->type) {
 481         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
 482                 if (vcpu->arch.xen.vcpu_info_set)
 483                         data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
 484                 else
 485                         data->u.gpa = GPA_INVALID;
 486                 r = 0;
 487                 break;
 488
 489         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 490                 if (vcpu->arch.xen.vcpu_time_info_set)
 491                         data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
 492                 else
 493                         data->u.gpa = GPA_INVALID;
 494                 r = 0;
 495                 break;
 496
 497         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
 498                 if (!sched_info_on()) {
 499                         r = -EOPNOTSUPP;
 500                         break;
 501                 }
 502                 if (vcpu->arch.xen.runstate_set) {
 503                         data->u.gpa = vcpu->arch.xen.runstate_cache.gpa;
 504                         r = 0;
 505                 }
 506                 break;
 507
 508         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
 509                 if (!sched_info_on()) {
 510                         r = -EOPNOTSUPP;
 511                         break;
 512                 }
 513                 data->u.runstate.state = vcpu->arch.xen.current_runstate;
 514                 r = 0;
 515                 break;
 516
 517         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
 518                 if (!sched_info_on()) {
 519                         r = -EOPNOTSUPP;
 520                         break;
 521                 }
 522                 data->u.runstate.state = vcpu->arch.xen.current_runstate;
 523                 data->u.runstate.state_entry_time =
 524                         vcpu->arch.xen.runstate_entry_time;
 525                 data->u.runstate.time_running =
 526                         vcpu->arch.xen.runstate_times[RUNSTATE_running];
 527                 data->u.runstate.time_runnable =
 528                         vcpu->arch.xen.runstate_times[RUNSTATE_runnable];
 529                 data->u.runstate.time_blocked =
 530                         vcpu->arch.xen.runstate_times[RUNSTATE_blocked];
 531                 data->u.runstate.time_offline =
 532                         vcpu->arch.xen.runstate_times[RUNSTATE_offline];
 533                 r = 0;
 534                 break;
 535
 536         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
 537                 r = -EINVAL;
 538                 break;
 539
 540         default:
 541                 break;
 542         }
 543
 544         mutex_unlock(&vcpu->kvm->lock);
 545         return r;
 546 }
 547
 548 int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
 549 {
 550         struct kvm *kvm = vcpu->kvm;
 551         u32 page_num = data & ~PAGE_MASK;
 552         u64 page_addr = data & PAGE_MASK;
 553         bool lm = is_long_mode(vcpu);
 554
 555         /* Latch long_mode for shared_info pages etc. */
 556         vcpu->kvm->arch.xen.long_mode = lm;
 557
 558         /*
 559          * If Xen hypercall intercept is enabled, fill the hypercall
 560          * page with VMCALL/VMMCALL instructions since that's what
 561          * we catch. Else the VMM has provided the hypercall pages
 562          * with instructions of its own choosing, so use those.
 563          */
 564         if (kvm_xen_hypercall_enabled(kvm)) {
 565                 u8 instructions[32];
 566                 int i;
 567
 568                 if (page_num)
 569                         return 1;
 570
 571                 /* mov imm32, %eax */
 572                 instructions[0] = 0xb8;
 573
 574                 /* vmcall / vmmcall */
 575                 kvm_x86_ops.patch_hypercall(vcpu, instructions + 5);
 576
 577                 /* ret */
 578                 instructions[8] = 0xc3;
 579
 580                 /* int3 to pad */
 581                 memset(instructions + 9, 0xcc, sizeof(instructions) - 9);
 582
 583                 for (i = 0; i < PAGE_SIZE / sizeof(instructions); i++) {
 584                         *(u32 *)&instructions[1] = i;
 585                         if (kvm_vcpu_write_guest(vcpu,
 586                                                  page_addr + (i * sizeof(instructions)),
 587                                                  instructions, sizeof(instructions)))
 588                                 return 1;
 589                 }
 590         } else {
 591                 /*
 592                  * Note, truncation is a non-issue as 'lm' is guaranteed to be
 593                  * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes.
 594                  */
 595                 hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64
 596                                      : kvm->arch.xen_hvm_config.blob_addr_32;
 597                 u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
 598                                   : kvm->arch.xen_hvm_config.blob_size_32;
 599                 u8 *page;
 600
 601                 if (page_num >= blob_size)
 602                         return 1;
 603
 604                 blob_addr += page_num * PAGE_SIZE;
 605
 606                 page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE);
 607                 if (IS_ERR(page))
 608                         return PTR_ERR(page);
 609
 610                 if (kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE)) {
 611                         kfree(page);
 612                         return 1;
 613                 }
 614         }
 615         return 0;
 616 }
 617
 618 int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
 619 {
 620         if (xhc->flags & ~KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL)
 621                 return -EINVAL;
 622
 623         /*
 624          * With hypercall interception the kernel generates its own
 625          * hypercall page so it must not be provided.
 626          */
 627         if ((xhc->flags & KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) &&
 628             (xhc->blob_addr_32 || xhc->blob_addr_64 ||
 629              xhc->blob_size_32 || xhc->blob_size_64))
 630                 return -EINVAL;
 631
 632         mutex_lock(&kvm->lock);
 633
 634         if (xhc->msr && !kvm->arch.xen_hvm_config.msr)
 635                 static_branch_inc(&kvm_xen_enabled.key);
 636         else if (!xhc->msr && kvm->arch.xen_hvm_config.msr)
 637                 static_branch_slow_dec_deferred(&kvm_xen_enabled);
 638
 639         memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc));
 640
 641         mutex_unlock(&kvm->lock);
 642         return 0;
 643 }
 644
 645 void kvm_xen_init_vm(struct kvm *kvm)
 646 {
 647         kvm->arch.xen.shinfo_gfn = GPA_INVALID;
 648 }
 649
 650 void kvm_xen_destroy_vm(struct kvm *kvm)
 651 {
 652         if (kvm->arch.xen_hvm_config.msr)
 653                 static_branch_slow_dec_deferred(&kvm_xen_enabled);
 654 }
 655
 656 static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
 657 {
 658         kvm_rax_write(vcpu, result);
 659         return kvm_skip_emulated_instruction(vcpu);
 660 }
 661
 662 static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
 663 {
 664         struct kvm_run *run = vcpu->run;
 665
 666         if (unlikely(!kvm_is_linear_rip(vcpu, vcpu->arch.xen.hypercall_rip)))
 667                 return 1;
 668
 669         return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result);
 670 }
 671
 672 int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
 673 {
 674         bool longmode;
 675         u64 input, params[6];
 676
 677         input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);
 678
 679         /* Hyper-V hypercalls get bit 31 set in EAX */
 680         if ((input & 0x80000000) &&
 681             kvm_hv_hypercall_enabled(vcpu))
 682                 return kvm_hv_hypercall(vcpu);
 683
 684         longmode = is_64_bit_mode(vcpu);
 685         if (!longmode) {
 686                 params[0] = (u32)kvm_rbx_read(vcpu);
 687                 params[1] = (u32)kvm_rcx_read(vcpu);
 688                 params[2] = (u32)kvm_rdx_read(vcpu);
 689                 params[3] = (u32)kvm_rsi_read(vcpu);
 690                 params[4] = (u32)kvm_rdi_read(vcpu);
 691                 params[5] = (u32)kvm_rbp_read(vcpu);
 692         }
 693 #ifdef CONFIG_X86_64
 694         else {
 695                 params[0] = (u64)kvm_rdi_read(vcpu);
 696                 params[1] = (u64)kvm_rsi_read(vcpu);
 697                 params[2] = (u64)kvm_rdx_read(vcpu);
 698                 params[3] = (u64)kvm_r10_read(vcpu);
 699                 params[4] = (u64)kvm_r8_read(vcpu);
 700                 params[5] = (u64)kvm_r9_read(vcpu);
 701         }
 702 #endif
 703         trace_kvm_xen_hypercall(input, params[0], params[1], params[2],
 704                                 params[3], params[4], params[5]);
 705
 706         vcpu->run->exit_reason = KVM_EXIT_XEN;
 707         vcpu->run->xen.type = KVM_EXIT_XEN_HCALL;
 708         vcpu->run->xen.u.hcall.longmode = longmode;
 709         vcpu->run->xen.u.hcall.cpl = kvm_x86_ops.get_cpl(vcpu);
 710         vcpu->run->xen.u.hcall.input = input;
 711         vcpu->run->xen.u.hcall.params[0] = params[0];
 712         vcpu->run->xen.u.hcall.params[1] = params[1];
 713         vcpu->run->xen.u.hcall.params[2] = params[2];
 714         vcpu->run->xen.u.hcall.params[3] = params[3];
 715         vcpu->run->xen.u.hcall.params[4] = params[4];
 716         vcpu->run->xen.u.hcall.params[5] = params[5];
 717         vcpu->arch.xen.hypercall_rip = kvm_get_linear_rip(vcpu);
 718         vcpu->arch.complete_userspace_io =
 719                 kvm_xen_hypercall_complete_userspace;
 720
 721         return 0;
 722 }