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 #include "lapic.h"
  13
  14 #include <linux/eventfd.h>
  15 #include <linux/kvm_host.h>
  16 #include <linux/sched/stat.h>
  17
  18 #include <trace/events/kvm.h>
  19 #include <xen/interface/xen.h>
  20 #include <xen/interface/vcpu.h>
  21 #include <xen/interface/version.h>
  22 #include <xen/interface/event_channel.h>
  23 #include <xen/interface/sched.h>
  24
  25 #include "trace.h"
  26
  27 static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm);
  28 static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
  29 static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r);
  30
  31 DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ);
  32
  33 static int kvm_xen_shared_info_init(struct kvm *kvm, gfn_t gfn)
  34 {
  35         struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
  36         struct pvclock_wall_clock *wc;
  37         gpa_t gpa = gfn_to_gpa(gfn);
  38         u32 *wc_sec_hi;
  39         u32 wc_version;
  40         u64 wall_nsec;
  41         int ret = 0;
  42         int idx = srcu_read_lock(&kvm->srcu);
  43
  44         if (gfn == GPA_INVALID) {
  45                 kvm_gfn_to_pfn_cache_destroy(kvm, gpc);
  46                 goto out;
  47         }
  48
  49         do {
  50                 ret = kvm_gfn_to_pfn_cache_init(kvm, gpc, NULL, KVM_HOST_USES_PFN,
  51                                                 gpa, PAGE_SIZE);
  52                 if (ret)
  53                         goto out;
  54
  55                 /*
  56                  * This code mirrors kvm_write_wall_clock() except that it writes
  57                  * directly through the pfn cache and doesn't mark the page dirty.
  58                  */
  59                 wall_nsec = ktime_get_real_ns() - get_kvmclock_ns(kvm);
  60
  61                 /* It could be invalid again already, so we need to check */
  62                 read_lock_irq(&gpc->lock);
  63
  64                 if (gpc->valid)
  65                         break;
  66
  67                 read_unlock_irq(&gpc->lock);
  68         } while (1);
  69
  70         /* Paranoia checks on the 32-bit struct layout */
  71         BUILD_BUG_ON(offsetof(struct compat_shared_info, wc) != 0x900);
  72         BUILD_BUG_ON(offsetof(struct compat_shared_info, arch.wc_sec_hi) != 0x924);
  73         BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0);
  74
  75 #ifdef CONFIG_X86_64
  76         /* Paranoia checks on the 64-bit struct layout */
  77         BUILD_BUG_ON(offsetof(struct shared_info, wc) != 0xc00);
  78         BUILD_BUG_ON(offsetof(struct shared_info, wc_sec_hi) != 0xc0c);
  79
  80         if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
  81                 struct shared_info *shinfo = gpc->khva;
  82
  83                 wc_sec_hi = &shinfo->wc_sec_hi;
  84                 wc = &shinfo->wc;
  85         } else
  86 #endif
  87         {
  88                 struct compat_shared_info *shinfo = gpc->khva;
  89
  90                 wc_sec_hi = &shinfo->arch.wc_sec_hi;
  91                 wc = &shinfo->wc;
  92         }
  93
  94         /* Increment and ensure an odd value */
  95         wc_version = wc->version = (wc->version + 1) | 1;
  96         smp_wmb();
  97
  98         wc->nsec = do_div(wall_nsec,  1000000000);
  99         wc->sec = (u32)wall_nsec;
 100         *wc_sec_hi = wall_nsec >> 32;
 101         smp_wmb();
 102
 103         wc->version = wc_version + 1;
 104         read_unlock_irq(&gpc->lock);
 105
 106         kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE);
 107
 108 out:
 109         srcu_read_unlock(&kvm->srcu, idx);
 110         return ret;
 111 }
 112
 113 void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu)
 114 {
 115         if (atomic_read(&vcpu->arch.xen.timer_pending) > 0) {
 116                 struct kvm_xen_evtchn e;
 117
 118                 e.vcpu_id = vcpu->vcpu_id;
 119                 e.vcpu_idx = vcpu->vcpu_idx;
 120                 e.port = vcpu->arch.xen.timer_virq;
 121                 e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
 122
 123                 kvm_xen_set_evtchn(&e, vcpu->kvm);
 124
 125                 vcpu->arch.xen.timer_expires = 0;
 126                 atomic_set(&vcpu->arch.xen.timer_pending, 0);
 127         }
 128 }
 129
 130 static enum hrtimer_restart xen_timer_callback(struct hrtimer *timer)
 131 {
 132         struct kvm_vcpu *vcpu = container_of(timer, struct kvm_vcpu,
 133                                              arch.xen.timer);
 134         if (atomic_read(&vcpu->arch.xen.timer_pending))
 135                 return HRTIMER_NORESTART;
 136
 137         atomic_inc(&vcpu->arch.xen.timer_pending);
 138         kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
 139         kvm_vcpu_kick(vcpu);
 140
 141         return HRTIMER_NORESTART;
 142 }
 143
 144 static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 guest_abs, s64 delta_ns)
 145 {
 146         atomic_set(&vcpu->arch.xen.timer_pending, 0);
 147         vcpu->arch.xen.timer_expires = guest_abs;
 148
 149         if (delta_ns <= 0) {
 150                 xen_timer_callback(&vcpu->arch.xen.timer);
 151         } else {
 152                 ktime_t ktime_now = ktime_get();
 153                 hrtimer_start(&vcpu->arch.xen.timer,
 154                               ktime_add_ns(ktime_now, delta_ns),
 155                               HRTIMER_MODE_ABS_HARD);
 156         }
 157 }
 158
 159 static void kvm_xen_stop_timer(struct kvm_vcpu *vcpu)
 160 {
 161         hrtimer_cancel(&vcpu->arch.xen.timer);
 162         vcpu->arch.xen.timer_expires = 0;
 163         atomic_set(&vcpu->arch.xen.timer_pending, 0);
 164 }
 165
 166 static void kvm_xen_init_timer(struct kvm_vcpu *vcpu)
 167 {
 168         hrtimer_init(&vcpu->arch.xen.timer, CLOCK_MONOTONIC,
 169                      HRTIMER_MODE_ABS_HARD);
 170         vcpu->arch.xen.timer.function = xen_timer_callback;
 171 }
 172
 173 static void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
 174 {
 175         struct kvm_vcpu_xen *vx = &v->arch.xen;
 176         u64 now = get_kvmclock_ns(v->kvm);
 177         u64 delta_ns = now - vx->runstate_entry_time;
 178         u64 run_delay = current->sched_info.run_delay;
 179
 180         if (unlikely(!vx->runstate_entry_time))
 181                 vx->current_runstate = RUNSTATE_offline;
 182
 183         /*
 184          * Time waiting for the scheduler isn't "stolen" if the
 185          * vCPU wasn't running anyway.
 186          */
 187         if (vx->current_runstate == RUNSTATE_running) {
 188                 u64 steal_ns = run_delay - vx->last_steal;
 189
 190                 delta_ns -= steal_ns;
 191
 192                 vx->runstate_times[RUNSTATE_runnable] += steal_ns;
 193         }
 194         vx->last_steal = run_delay;
 195
 196         vx->runstate_times[vx->current_runstate] += delta_ns;
 197         vx->current_runstate = state;
 198         vx->runstate_entry_time = now;
 199 }
 200
 201 void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, int state)
 202 {
 203         struct kvm_vcpu_xen *vx = &v->arch.xen;
 204         struct gfn_to_pfn_cache *gpc = &vx->runstate_cache;
 205         uint64_t *user_times;
 206         unsigned long flags;
 207         size_t user_len;
 208         int *user_state;
 209
 210         kvm_xen_update_runstate(v, state);
 211
 212         if (!vx->runstate_cache.active)
 213                 return;
 214
 215         if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode)
 216                 user_len = sizeof(struct vcpu_runstate_info);
 217         else
 218                 user_len = sizeof(struct compat_vcpu_runstate_info);
 219
 220         read_lock_irqsave(&gpc->lock, flags);
 221         while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc, gpc->gpa,
 222                                            user_len)) {
 223                 read_unlock_irqrestore(&gpc->lock, flags);
 224
 225                 /* When invoked from kvm_sched_out() we cannot sleep */
 226                 if (state == RUNSTATE_runnable)
 227                         return;
 228
 229                 if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc, gpc->gpa, user_len))
 230                         return;
 231
 232                 read_lock_irqsave(&gpc->lock, flags);
 233         }
 234
 235         /*
 236          * The only difference between 32-bit and 64-bit versions of the
 237          * runstate struct us the alignment of uint64_t in 32-bit, which
 238          * means that the 64-bit version has an additional 4 bytes of
 239          * padding after the first field 'state'.
 240          *
 241          * So we use 'int __user *user_state' to point to the state field,
 242          * and 'uint64_t __user *user_times' for runstate_entry_time. So
 243          * the actual array of time[] in each state starts at user_times[1].
 244          */
 245         BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) != 0);
 246         BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state) != 0);
 247         BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c);
 248 #ifdef CONFIG_X86_64
 249         BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
 250                      offsetof(struct compat_vcpu_runstate_info, state_entry_time) + 4);
 251         BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, time) !=
 252                      offsetof(struct compat_vcpu_runstate_info, time) + 4);
 253 #endif
 254
 255         user_state = gpc->khva;
 256
 257         if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode)
 258                 user_times = gpc->khva + offsetof(struct vcpu_runstate_info,
 259                                                   state_entry_time);
 260         else
 261                 user_times = gpc->khva + offsetof(struct compat_vcpu_runstate_info,
 262                                                   state_entry_time);
 263
 264         /*
 265          * First write the updated state_entry_time at the appropriate
 266          * location determined by 'offset'.
 267          */
 268         BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state_entry_time) !=
 269                      sizeof(user_times[0]));
 270         BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) !=
 271                      sizeof(user_times[0]));
 272
 273         user_times[0] = vx->runstate_entry_time | XEN_RUNSTATE_UPDATE;
 274         smp_wmb();
 275
 276         /*
 277          * Next, write the new runstate. This is in the *same* place
 278          * for 32-bit and 64-bit guests, asserted here for paranoia.
 279          */
 280         BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) !=
 281                      offsetof(struct compat_vcpu_runstate_info, state));
 282         BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state) !=
 283                      sizeof(vx->current_runstate));
 284         BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state) !=
 285                      sizeof(vx->current_runstate));
 286
 287         *user_state = vx->current_runstate;
 288
 289         /*
 290          * Write the actual runstate times immediately after the
 291          * runstate_entry_time.
 292          */
 293         BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
 294                      offsetof(struct vcpu_runstate_info, time) - sizeof(u64));
 295         BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state_entry_time) !=
 296                      offsetof(struct compat_vcpu_runstate_info, time) - sizeof(u64));
 297         BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
 298                      sizeof_field(struct compat_vcpu_runstate_info, time));
 299         BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
 300                      sizeof(vx->runstate_times));
 301
 302         memcpy(user_times + 1, vx->runstate_times, sizeof(vx->runstate_times));
 303         smp_wmb();
 304
 305         /*
 306          * Finally, clear the XEN_RUNSTATE_UPDATE bit in the guest's
 307          * runstate_entry_time field.
 308          */
 309         user_times[0] &= ~XEN_RUNSTATE_UPDATE;
 310         smp_wmb();
 311
 312         read_unlock_irqrestore(&gpc->lock, flags);
 313
 314         mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT);
 315 }
 316
 317 static void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v)
 318 {
 319         struct kvm_lapic_irq irq = { };
 320         int r;
 321
 322         irq.dest_id = v->vcpu_id;
 323         irq.vector = v->arch.xen.upcall_vector;
 324         irq.dest_mode = APIC_DEST_PHYSICAL;
 325         irq.shorthand = APIC_DEST_NOSHORT;
 326         irq.delivery_mode = APIC_DM_FIXED;
 327         irq.level = 1;
 328
 329         /* The fast version will always work for physical unicast */
 330         WARN_ON_ONCE(!kvm_irq_delivery_to_apic_fast(v->kvm, NULL, &irq, &r, NULL));
 331 }
 332
 333 /*
 334  * On event channel delivery, the vcpu_info may not have been accessible.
 335  * In that case, there are bits in vcpu->arch.xen.evtchn_pending_sel which
 336  * need to be marked into the vcpu_info (and evtchn_upcall_pending set).
 337  * Do so now that we can sleep in the context of the vCPU to bring the
 338  * page in, and refresh the pfn cache for it.
 339  */
 340 void kvm_xen_inject_pending_events(struct kvm_vcpu *v)
 341 {
 342         unsigned long evtchn_pending_sel = READ_ONCE(v->arch.xen.evtchn_pending_sel);
 343         struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
 344         unsigned long flags;
 345
 346         if (!evtchn_pending_sel)
 347                 return;
 348
 349         /*
 350          * Yes, this is an open-coded loop. But that's just what put_user()
 351          * does anyway. Page it in and retry the instruction. We're just a
 352          * little more honest about it.
 353          */
 354         read_lock_irqsave(&gpc->lock, flags);
 355         while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc, gpc->gpa,
 356                                            sizeof(struct vcpu_info))) {
 357                 read_unlock_irqrestore(&gpc->lock, flags);
 358
 359                 if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc, gpc->gpa,
 360                                                  sizeof(struct vcpu_info)))
 361                         return;
 362
 363                 read_lock_irqsave(&gpc->lock, flags);
 364         }
 365
 366         /* Now gpc->khva is a valid kernel address for the vcpu_info */
 367         if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) {
 368                 struct vcpu_info *vi = gpc->khva;
 369
 370                 asm volatile(LOCK_PREFIX "orq %0, %1\n"
 371                              "notq %0\n"
 372                              LOCK_PREFIX "andq %0, %2\n"
 373                              : "=r" (evtchn_pending_sel),
 374                                "+m" (vi->evtchn_pending_sel),
 375                                "+m" (v->arch.xen.evtchn_pending_sel)
 376                              : "0" (evtchn_pending_sel));
 377                 WRITE_ONCE(vi->evtchn_upcall_pending, 1);
 378         } else {
 379                 u32 evtchn_pending_sel32 = evtchn_pending_sel;
 380                 struct compat_vcpu_info *vi = gpc->khva;
 381
 382                 asm volatile(LOCK_PREFIX "orl %0, %1\n"
 383                              "notl %0\n"
 384                              LOCK_PREFIX "andl %0, %2\n"
 385                              : "=r" (evtchn_pending_sel32),
 386                                "+m" (vi->evtchn_pending_sel),
 387                                "+m" (v->arch.xen.evtchn_pending_sel)
 388                              : "0" (evtchn_pending_sel32));
 389                 WRITE_ONCE(vi->evtchn_upcall_pending, 1);
 390         }
 391         read_unlock_irqrestore(&gpc->lock, flags);
 392
 393         /* For the per-vCPU lapic vector, deliver it as MSI. */
 394         if (v->arch.xen.upcall_vector)
 395                 kvm_xen_inject_vcpu_vector(v);
 396
 397         mark_page_dirty_in_slot(v->kvm, gpc->memslot, gpc->gpa >> PAGE_SHIFT);
 398 }
 399
 400 int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
 401 {
 402         struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
 403         unsigned long flags;
 404         u8 rc = 0;
 405
 406         /*
 407          * If the global upcall vector (HVMIRQ_callback_vector) is set and
 408          * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending.
 409          */
 410
 411         /* No need for compat handling here */
 412         BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) !=
 413                      offsetof(struct compat_vcpu_info, evtchn_upcall_pending));
 414         BUILD_BUG_ON(sizeof(rc) !=
 415                      sizeof_field(struct vcpu_info, evtchn_upcall_pending));
 416         BUILD_BUG_ON(sizeof(rc) !=
 417                      sizeof_field(struct compat_vcpu_info, evtchn_upcall_pending));
 418
 419         read_lock_irqsave(&gpc->lock, flags);
 420         while (!kvm_gfn_to_pfn_cache_check(v->kvm, gpc, gpc->gpa,
 421                                            sizeof(struct vcpu_info))) {
 422                 read_unlock_irqrestore(&gpc->lock, flags);
 423
 424                 /*
 425                  * This function gets called from kvm_vcpu_block() after setting the
 426                  * task to TASK_INTERRUPTIBLE, to see if it needs to wake immediately
 427                  * from a HLT. So we really mustn't sleep. If the page ended up absent
 428                  * at that point, just return 1 in order to trigger an immediate wake,
 429                  * and we'll end up getting called again from a context where we *can*
 430                  * fault in the page and wait for it.
 431                  */
 432                 if (in_atomic() || !task_is_running(current))
 433                         return 1;
 434
 435                 if (kvm_gfn_to_pfn_cache_refresh(v->kvm, gpc, gpc->gpa,
 436                                                  sizeof(struct vcpu_info))) {
 437                         /*
 438                          * If this failed, userspace has screwed up the
 439                          * vcpu_info mapping. No interrupts for you.
 440                          */
 441                         return 0;
 442                 }
 443                 read_lock_irqsave(&gpc->lock, flags);
 444         }
 445
 446         rc = ((struct vcpu_info *)gpc->khva)->evtchn_upcall_pending;
 447         read_unlock_irqrestore(&gpc->lock, flags);
 448         return rc;
 449 }
 450
 451 int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 452 {
 453         int r = -ENOENT;
 454
 455
 456         switch (data->type) {
 457         case KVM_XEN_ATTR_TYPE_LONG_MODE:
 458                 if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) {
 459                         r = -EINVAL;
 460                 } else {
 461                         mutex_lock(&kvm->lock);
 462                         kvm->arch.xen.long_mode = !!data->u.long_mode;
 463                         mutex_unlock(&kvm->lock);
 464                         r = 0;
 465                 }
 466                 break;
 467
 468         case KVM_XEN_ATTR_TYPE_SHARED_INFO:
 469                 mutex_lock(&kvm->lock);
 470                 r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
 471                 mutex_unlock(&kvm->lock);
 472                 break;
 473
 474         case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
 475                 if (data->u.vector && data->u.vector < 0x10)
 476                         r = -EINVAL;
 477                 else {
 478                         mutex_lock(&kvm->lock);
 479                         kvm->arch.xen.upcall_vector = data->u.vector;
 480                         mutex_unlock(&kvm->lock);
 481                         r = 0;
 482                 }
 483                 break;
 484
 485         case KVM_XEN_ATTR_TYPE_EVTCHN:
 486                 r = kvm_xen_setattr_evtchn(kvm, data);
 487                 break;
 488
 489         case KVM_XEN_ATTR_TYPE_XEN_VERSION:
 490                 mutex_lock(&kvm->lock);
 491                 kvm->arch.xen.xen_version = data->u.xen_version;
 492                 mutex_unlock(&kvm->lock);
 493                 r = 0;
 494                 break;
 495
 496         default:
 497                 break;
 498         }
 499
 500         return r;
 501 }
 502
 503 int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 504 {
 505         int r = -ENOENT;
 506
 507         mutex_lock(&kvm->lock);
 508
 509         switch (data->type) {
 510         case KVM_XEN_ATTR_TYPE_LONG_MODE:
 511                 data->u.long_mode = kvm->arch.xen.long_mode;
 512                 r = 0;
 513                 break;
 514
 515         case KVM_XEN_ATTR_TYPE_SHARED_INFO:
 516                 if (kvm->arch.xen.shinfo_cache.active)
 517                         data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_cache.gpa);
 518                 else
 519                         data->u.shared_info.gfn = GPA_INVALID;
 520                 r = 0;
 521                 break;
 522
 523         case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
 524                 data->u.vector = kvm->arch.xen.upcall_vector;
 525                 r = 0;
 526                 break;
 527
 528         case KVM_XEN_ATTR_TYPE_XEN_VERSION:
 529                 data->u.xen_version = kvm->arch.xen.xen_version;
 530                 r = 0;
 531                 break;
 532
 533         default:
 534                 break;
 535         }
 536
 537         mutex_unlock(&kvm->lock);
 538         return r;
 539 }
 540
 541 int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 542 {
 543         int idx, r = -ENOENT;
 544
 545         mutex_lock(&vcpu->kvm->lock);
 546         idx = srcu_read_lock(&vcpu->kvm->srcu);
 547
 548         switch (data->type) {
 549         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
 550                 /* No compat necessary here. */
 551                 BUILD_BUG_ON(sizeof(struct vcpu_info) !=
 552                              sizeof(struct compat_vcpu_info));
 553                 BUILD_BUG_ON(offsetof(struct vcpu_info, time) !=
 554                              offsetof(struct compat_vcpu_info, time));
 555
 556                 if (data->u.gpa == GPA_INVALID) {
 557                         kvm_gfn_to_pfn_cache_destroy(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache);
 558                         r = 0;
 559                         break;
 560                 }
 561
 562                 r = kvm_gfn_to_pfn_cache_init(vcpu->kvm,
 563                                               &vcpu->arch.xen.vcpu_info_cache,
 564                                               NULL, KVM_HOST_USES_PFN, data->u.gpa,
 565                                               sizeof(struct vcpu_info));
 566                 if (!r)
 567                         kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 568
 569                 break;
 570
 571         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 572                 if (data->u.gpa == GPA_INVALID) {
 573                         kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
 574                                                      &vcpu->arch.xen.vcpu_time_info_cache);
 575                         r = 0;
 576                         break;
 577                 }
 578
 579                 r = kvm_gfn_to_pfn_cache_init(vcpu->kvm,
 580                                               &vcpu->arch.xen.vcpu_time_info_cache,
 581                                               NULL, KVM_HOST_USES_PFN, data->u.gpa,
 582                                               sizeof(struct pvclock_vcpu_time_info));
 583                 if (!r)
 584                         kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 585                 break;
 586
 587         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
 588                 if (!sched_info_on()) {
 589                         r = -EOPNOTSUPP;
 590                         break;
 591                 }
 592                 if (data->u.gpa == GPA_INVALID) {
 593                         kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
 594                                                      &vcpu->arch.xen.runstate_cache);
 595                         r = 0;
 596                         break;
 597                 }
 598
 599                 r = kvm_gfn_to_pfn_cache_init(vcpu->kvm,
 600                                               &vcpu->arch.xen.runstate_cache,
 601                                               NULL, KVM_HOST_USES_PFN, data->u.gpa,
 602                                               sizeof(struct vcpu_runstate_info));
 603                 break;
 604
 605         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
 606                 if (!sched_info_on()) {
 607                         r = -EOPNOTSUPP;
 608                         break;
 609                 }
 610                 if (data->u.runstate.state > RUNSTATE_offline) {
 611                         r = -EINVAL;
 612                         break;
 613                 }
 614
 615                 kvm_xen_update_runstate(vcpu, data->u.runstate.state);
 616                 r = 0;
 617                 break;
 618
 619         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
 620                 if (!sched_info_on()) {
 621                         r = -EOPNOTSUPP;
 622                         break;
 623                 }
 624                 if (data->u.runstate.state > RUNSTATE_offline) {
 625                         r = -EINVAL;
 626                         break;
 627                 }
 628                 if (data->u.runstate.state_entry_time !=
 629                     (data->u.runstate.time_running +
 630                      data->u.runstate.time_runnable +
 631                      data->u.runstate.time_blocked +
 632                      data->u.runstate.time_offline)) {
 633                         r = -EINVAL;
 634                         break;
 635                 }
 636                 if (get_kvmclock_ns(vcpu->kvm) <
 637                     data->u.runstate.state_entry_time) {
 638                         r = -EINVAL;
 639                         break;
 640                 }
 641
 642                 vcpu->arch.xen.current_runstate = data->u.runstate.state;
 643                 vcpu->arch.xen.runstate_entry_time =
 644                         data->u.runstate.state_entry_time;
 645                 vcpu->arch.xen.runstate_times[RUNSTATE_running] =
 646                         data->u.runstate.time_running;
 647                 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] =
 648                         data->u.runstate.time_runnable;
 649                 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] =
 650                         data->u.runstate.time_blocked;
 651                 vcpu->arch.xen.runstate_times[RUNSTATE_offline] =
 652                         data->u.runstate.time_offline;
 653                 vcpu->arch.xen.last_steal = current->sched_info.run_delay;
 654                 r = 0;
 655                 break;
 656
 657         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
 658                 if (!sched_info_on()) {
 659                         r = -EOPNOTSUPP;
 660                         break;
 661                 }
 662                 if (data->u.runstate.state > RUNSTATE_offline &&
 663                     data->u.runstate.state != (u64)-1) {
 664                         r = -EINVAL;
 665                         break;
 666                 }
 667                 /* The adjustment must add up */
 668                 if (data->u.runstate.state_entry_time !=
 669                     (data->u.runstate.time_running +
 670                      data->u.runstate.time_runnable +
 671                      data->u.runstate.time_blocked +
 672                      data->u.runstate.time_offline)) {
 673                         r = -EINVAL;
 674                         break;
 675                 }
 676
 677                 if (get_kvmclock_ns(vcpu->kvm) <
 678                     (vcpu->arch.xen.runstate_entry_time +
 679                      data->u.runstate.state_entry_time)) {
 680                         r = -EINVAL;
 681                         break;
 682                 }
 683
 684                 vcpu->arch.xen.runstate_entry_time +=
 685                         data->u.runstate.state_entry_time;
 686                 vcpu->arch.xen.runstate_times[RUNSTATE_running] +=
 687                         data->u.runstate.time_running;
 688                 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] +=
 689                         data->u.runstate.time_runnable;
 690                 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] +=
 691                         data->u.runstate.time_blocked;
 692                 vcpu->arch.xen.runstate_times[RUNSTATE_offline] +=
 693                         data->u.runstate.time_offline;
 694
 695                 if (data->u.runstate.state <= RUNSTATE_offline)
 696                         kvm_xen_update_runstate(vcpu, data->u.runstate.state);
 697                 r = 0;
 698                 break;
 699
 700         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
 701                 if (data->u.vcpu_id >= KVM_MAX_VCPUS)
 702                         r = -EINVAL;
 703                 else {
 704                         vcpu->arch.xen.vcpu_id = data->u.vcpu_id;
 705                         r = 0;
 706                 }
 707                 break;
 708
 709         case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
 710                 if (data->u.timer.port) {
 711                         if (data->u.timer.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) {
 712                                 r = -EINVAL;
 713                                 break;
 714                         }
 715                         vcpu->arch.xen.timer_virq = data->u.timer.port;
 716                         kvm_xen_init_timer(vcpu);
 717
 718                         /* Restart the timer if it's set */
 719                         if (data->u.timer.expires_ns)
 720                                 kvm_xen_start_timer(vcpu, data->u.timer.expires_ns,
 721                                                     data->u.timer.expires_ns -
 722                                                     get_kvmclock_ns(vcpu->kvm));
 723                 } else if (kvm_xen_timer_enabled(vcpu)) {
 724                         kvm_xen_stop_timer(vcpu);
 725                         vcpu->arch.xen.timer_virq = 0;
 726                 }
 727
 728                 r = 0;
 729                 break;
 730
 731         case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
 732                 if (data->u.vector && data->u.vector < 0x10)
 733                         r = -EINVAL;
 734                 else {
 735                         vcpu->arch.xen.upcall_vector = data->u.vector;
 736                         r = 0;
 737                 }
 738                 break;
 739
 740         default:
 741                 break;
 742         }
 743
 744         srcu_read_unlock(&vcpu->kvm->srcu, idx);
 745         mutex_unlock(&vcpu->kvm->lock);
 746         return r;
 747 }
 748
 749 int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
 750 {
 751         int r = -ENOENT;
 752
 753         mutex_lock(&vcpu->kvm->lock);
 754
 755         switch (data->type) {
 756         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
 757                 if (vcpu->arch.xen.vcpu_info_cache.active)
 758                         data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
 759                 else
 760                         data->u.gpa = GPA_INVALID;
 761                 r = 0;
 762                 break;
 763
 764         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
 765                 if (vcpu->arch.xen.vcpu_time_info_cache.active)
 766                         data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
 767                 else
 768                         data->u.gpa = GPA_INVALID;
 769                 r = 0;
 770                 break;
 771
 772         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
 773                 if (!sched_info_on()) {
 774                         r = -EOPNOTSUPP;
 775                         break;
 776                 }
 777                 if (vcpu->arch.xen.runstate_cache.active) {
 778                         data->u.gpa = vcpu->arch.xen.runstate_cache.gpa;
 779                         r = 0;
 780                 }
 781                 break;
 782
 783         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
 784                 if (!sched_info_on()) {
 785                         r = -EOPNOTSUPP;
 786                         break;
 787                 }
 788                 data->u.runstate.state = vcpu->arch.xen.current_runstate;
 789                 r = 0;
 790                 break;
 791
 792         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
 793                 if (!sched_info_on()) {
 794                         r = -EOPNOTSUPP;
 795                         break;
 796                 }
 797                 data->u.runstate.state = vcpu->arch.xen.current_runstate;
 798                 data->u.runstate.state_entry_time =
 799                         vcpu->arch.xen.runstate_entry_time;
 800                 data->u.runstate.time_running =
 801                         vcpu->arch.xen.runstate_times[RUNSTATE_running];
 802                 data->u.runstate.time_runnable =
 803                         vcpu->arch.xen.runstate_times[RUNSTATE_runnable];
 804                 data->u.runstate.time_blocked =
 805                         vcpu->arch.xen.runstate_times[RUNSTATE_blocked];
 806                 data->u.runstate.time_offline =
 807                         vcpu->arch.xen.runstate_times[RUNSTATE_offline];
 808                 r = 0;
 809                 break;
 810
 811         case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
 812                 r = -EINVAL;
 813                 break;
 814
 815         case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
 816                 data->u.vcpu_id = vcpu->arch.xen.vcpu_id;
 817                 r = 0;
 818                 break;
 819
 820         case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
 821                 data->u.timer.port = vcpu->arch.xen.timer_virq;
 822                 data->u.timer.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
 823                 data->u.timer.expires_ns = vcpu->arch.xen.timer_expires;
 824                 r = 0;
 825                 break;
 826
 827         case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
 828                 data->u.vector = vcpu->arch.xen.upcall_vector;
 829                 r = 0;
 830                 break;
 831
 832         default:
 833                 break;
 834         }
 835
 836         mutex_unlock(&vcpu->kvm->lock);
 837         return r;
 838 }
 839
 840 int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
 841 {
 842         struct kvm *kvm = vcpu->kvm;
 843         u32 page_num = data & ~PAGE_MASK;
 844         u64 page_addr = data & PAGE_MASK;
 845         bool lm = is_long_mode(vcpu);
 846
 847         /* Latch long_mode for shared_info pages etc. */
 848         vcpu->kvm->arch.xen.long_mode = lm;
 849
 850         /*
 851          * If Xen hypercall intercept is enabled, fill the hypercall
 852          * page with VMCALL/VMMCALL instructions since that's what
 853          * we catch. Else the VMM has provided the hypercall pages
 854          * with instructions of its own choosing, so use those.
 855          */
 856         if (kvm_xen_hypercall_enabled(kvm)) {
 857                 u8 instructions[32];
 858                 int i;
 859
 860                 if (page_num)
 861                         return 1;
 862
 863                 /* mov imm32, %eax */
 864                 instructions[0] = 0xb8;
 865
 866                 /* vmcall / vmmcall */
 867                 static_call(kvm_x86_patch_hypercall)(vcpu, instructions + 5);
 868
 869                 /* ret */
 870                 instructions[8] = 0xc3;
 871
 872                 /* int3 to pad */
 873                 memset(instructions + 9, 0xcc, sizeof(instructions) - 9);
 874
 875                 for (i = 0; i < PAGE_SIZE / sizeof(instructions); i++) {
 876                         *(u32 *)&instructions[1] = i;
 877                         if (kvm_vcpu_write_guest(vcpu,
 878                                                  page_addr + (i * sizeof(instructions)),
 879                                                  instructions, sizeof(instructions)))
 880                                 return 1;
 881                 }
 882         } else {
 883                 /*
 884                  * Note, truncation is a non-issue as 'lm' is guaranteed to be
 885                  * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes.
 886                  */
 887                 hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64
 888                                      : kvm->arch.xen_hvm_config.blob_addr_32;
 889                 u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
 890                                   : kvm->arch.xen_hvm_config.blob_size_32;
 891                 u8 *page;
 892
 893                 if (page_num >= blob_size)
 894                         return 1;
 895
 896                 blob_addr += page_num * PAGE_SIZE;
 897
 898                 page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE);
 899                 if (IS_ERR(page))
 900                         return PTR_ERR(page);
 901
 902                 if (kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE)) {
 903                         kfree(page);
 904                         return 1;
 905                 }
 906         }
 907         return 0;
 908 }
 909
 910 int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
 911 {
 912         /* Only some feature flags need to be *enabled* by userspace */
 913         u32 permitted_flags = KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL |
 914                 KVM_XEN_HVM_CONFIG_EVTCHN_SEND;
 915
 916         if (xhc->flags & ~permitted_flags)
 917                 return -EINVAL;
 918
 919         /*
 920          * With hypercall interception the kernel generates its own
 921          * hypercall page so it must not be provided.
 922          */
 923         if ((xhc->flags & KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) &&
 924             (xhc->blob_addr_32 || xhc->blob_addr_64 ||
 925              xhc->blob_size_32 || xhc->blob_size_64))
 926                 return -EINVAL;
 927
 928         mutex_lock(&kvm->lock);
 929
 930         if (xhc->msr && !kvm->arch.xen_hvm_config.msr)
 931                 static_branch_inc(&kvm_xen_enabled.key);
 932         else if (!xhc->msr && kvm->arch.xen_hvm_config.msr)
 933                 static_branch_slow_dec_deferred(&kvm_xen_enabled);
 934
 935         memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc));
 936
 937         mutex_unlock(&kvm->lock);
 938         return 0;
 939 }
 940
 941 static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
 942 {
 943         kvm_rax_write(vcpu, result);
 944         return kvm_skip_emulated_instruction(vcpu);
 945 }
 946
 947 static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
 948 {
 949         struct kvm_run *run = vcpu->run;
 950
 951         if (unlikely(!kvm_is_linear_rip(vcpu, vcpu->arch.xen.hypercall_rip)))
 952                 return 1;
 953
 954         return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result);
 955 }
 956
 957 static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports,
 958                                evtchn_port_t *ports)
 959 {
 960         struct kvm *kvm = vcpu->kvm;
 961         struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
 962         unsigned long *pending_bits;
 963         unsigned long flags;
 964         bool ret = true;
 965         int idx, i;
 966
 967         read_lock_irqsave(&gpc->lock, flags);
 968         idx = srcu_read_lock(&kvm->srcu);
 969         if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, PAGE_SIZE))
 970                 goto out_rcu;
 971
 972         ret = false;
 973         if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
 974                 struct shared_info *shinfo = gpc->khva;
 975                 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
 976         } else {
 977                 struct compat_shared_info *shinfo = gpc->khva;
 978                 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
 979         }
 980
 981         for (i = 0; i < nr_ports; i++) {
 982                 if (test_bit(ports[i], pending_bits)) {
 983                         ret = true;
 984                         break;
 985                 }
 986         }
 987
 988  out_rcu:
 989         srcu_read_unlock(&kvm->srcu, idx);
 990         read_unlock_irqrestore(&gpc->lock, flags);
 991
 992         return ret;
 993 }
 994
 995 static bool kvm_xen_schedop_poll(struct kvm_vcpu *vcpu, bool longmode,
 996                                  u64 param, u64 *r)
 997 {
 998         int idx, i;
 999         struct sched_poll sched_poll;
1000         evtchn_port_t port, *ports;
1001         gpa_t gpa;
1002
1003         if (!longmode || !lapic_in_kernel(vcpu) ||
1004             !(vcpu->kvm->arch.xen_hvm_config.flags & KVM_XEN_HVM_CONFIG_EVTCHN_SEND))
1005                 return false;
1006
1007         idx = srcu_read_lock(&vcpu->kvm->srcu);
1008         gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
1009         srcu_read_unlock(&vcpu->kvm->srcu, idx);
1010
1011         if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &sched_poll,
1012                                         sizeof(sched_poll))) {
1013                 *r = -EFAULT;
1014                 return true;
1015         }
1016
1017         if (unlikely(sched_poll.nr_ports > 1)) {
1018                 /* Xen (unofficially) limits number of pollers to 128 */
1019                 if (sched_poll.nr_ports > 128) {
1020                         *r = -EINVAL;
1021                         return true;
1022                 }
1023
1024                 ports = kmalloc_array(sched_poll.nr_ports,
1025                                       sizeof(*ports), GFP_KERNEL);
1026                 if (!ports) {
1027                         *r = -ENOMEM;
1028                         return true;
1029                 }
1030         } else
1031                 ports = &port;
1032
1033         for (i = 0; i < sched_poll.nr_ports; i++) {
1034                 idx = srcu_read_lock(&vcpu->kvm->srcu);
1035                 gpa = kvm_mmu_gva_to_gpa_system(vcpu,
1036                                                 (gva_t)(sched_poll.ports + i),
1037                                                 NULL);
1038                 srcu_read_unlock(&vcpu->kvm->srcu, idx);
1039
1040                 if (!gpa || kvm_vcpu_read_guest(vcpu, gpa,
1041                                                 &ports[i], sizeof(port))) {
1042                         *r = -EFAULT;
1043                         goto out;
1044                 }
1045         }
1046
1047         if (sched_poll.nr_ports == 1)
1048                 vcpu->arch.xen.poll_evtchn = port;
1049         else
1050                 vcpu->arch.xen.poll_evtchn = -1;
1051
1052         set_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.xen.poll_mask);
1053
1054         if (!wait_pending_event(vcpu, sched_poll.nr_ports, ports)) {
1055                 vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
1056
1057                 if (sched_poll.timeout)
1058                         mod_timer(&vcpu->arch.xen.poll_timer,
1059                                   jiffies + nsecs_to_jiffies(sched_poll.timeout));
1060
1061                 kvm_vcpu_halt(vcpu);
1062
1063                 if (sched_poll.timeout)
1064                         del_timer(&vcpu->arch.xen.poll_timer);
1065
1066                 vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
1067                 kvm_clear_request(KVM_REQ_UNHALT, vcpu);
1068         }
1069
1070         vcpu->arch.xen.poll_evtchn = 0;
1071         *r = 0;
1072 out:
1073         /* Really, this is only needed in case of timeout */
1074         clear_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.xen.poll_mask);
1075
1076         if (unlikely(sched_poll.nr_ports > 1))
1077                 kfree(ports);
1078         return true;
1079 }
1080
1081 static void cancel_evtchn_poll(struct timer_list *t)
1082 {
1083         struct kvm_vcpu *vcpu = from_timer(vcpu, t, arch.xen.poll_timer);
1084
1085         kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1086         kvm_vcpu_kick(vcpu);
1087 }
1088
1089 static bool kvm_xen_hcall_sched_op(struct kvm_vcpu *vcpu, bool longmode,
1090                                    int cmd, u64 param, u64 *r)
1091 {
1092         switch (cmd) {
1093         case SCHEDOP_poll:
1094                 if (kvm_xen_schedop_poll(vcpu, longmode, param, r))
1095                         return true;
1096                 fallthrough;
1097         case SCHEDOP_yield:
1098                 kvm_vcpu_on_spin(vcpu, true);
1099                 *r = 0;
1100                 return true;
1101         default:
1102                 break;
1103         }
1104
1105         return false;
1106 }
1107
1108 struct compat_vcpu_set_singleshot_timer {
1109     uint64_t timeout_abs_ns;
1110     uint32_t flags;
1111 } __attribute__((packed));
1112
1113 static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
1114                                   int vcpu_id, u64 param, u64 *r)
1115 {
1116         struct vcpu_set_singleshot_timer oneshot;
1117         s64 delta;
1118         gpa_t gpa;
1119         int idx;
1120
1121         if (!kvm_xen_timer_enabled(vcpu))
1122                 return false;
1123
1124         switch (cmd) {
1125         case VCPUOP_set_singleshot_timer:
1126                 if (vcpu->arch.xen.vcpu_id != vcpu_id) {
1127                         *r = -EINVAL;
1128                         return true;
1129                 }
1130                 idx = srcu_read_lock(&vcpu->kvm->srcu);
1131                 gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
1132                 srcu_read_unlock(&vcpu->kvm->srcu, idx);
1133
1134                 /*
1135                  * The only difference for 32-bit compat is the 4 bytes of
1136                  * padding after the interesting part of the structure. So
1137                  * for a faithful emulation of Xen we have to *try* to copy
1138                  * the padding and return -EFAULT if we can't. Otherwise we
1139                  * might as well just have copied the 12-byte 32-bit struct.
1140                  */
1141                 BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
1142                              offsetof(struct vcpu_set_singleshot_timer, timeout_abs_ns));
1143                 BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
1144                              sizeof_field(struct vcpu_set_singleshot_timer, timeout_abs_ns));
1145                 BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, flags) !=
1146                              offsetof(struct vcpu_set_singleshot_timer, flags));
1147                 BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, flags) !=
1148                              sizeof_field(struct vcpu_set_singleshot_timer, flags));
1149
1150                 if (!gpa ||
1151                     kvm_vcpu_read_guest(vcpu, gpa, &oneshot, longmode ? sizeof(oneshot) :
1152                                         sizeof(struct compat_vcpu_set_singleshot_timer))) {
1153                         *r = -EFAULT;
1154                         return true;
1155                 }
1156
1157                 delta = oneshot.timeout_abs_ns - get_kvmclock_ns(vcpu->kvm);
1158                 if ((oneshot.flags & VCPU_SSHOTTMR_future) && delta < 0) {
1159                         *r = -ETIME;
1160                         return true;
1161                 }
1162
1163                 kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, delta);
1164                 *r = 0;
1165                 return true;
1166
1167         case VCPUOP_stop_singleshot_timer:
1168                 if (vcpu->arch.xen.vcpu_id != vcpu_id) {
1169                         *r = -EINVAL;
1170                         return true;
1171                 }
1172                 kvm_xen_stop_timer(vcpu);
1173                 *r = 0;
1174                 return true;
1175         }
1176
1177         return false;
1178 }
1179
1180 static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout,
1181                                        u64 *r)
1182 {
1183         if (!kvm_xen_timer_enabled(vcpu))
1184                 return false;
1185
1186         if (timeout) {
1187                 uint64_t guest_now = get_kvmclock_ns(vcpu->kvm);
1188                 int64_t delta = timeout - guest_now;
1189
1190                 /* Xen has a 'Linux workaround' in do_set_timer_op() which
1191                  * checks for negative absolute timeout values (caused by
1192                  * integer overflow), and for values about 13 days in the
1193                  * future (2^50ns) which would be caused by jiffies
1194                  * overflow. For those cases, it sets the timeout 100ms in
1195                  * the future (not *too* soon, since if a guest really did
1196                  * set a long timeout on purpose we don't want to keep
1197                  * churning CPU time by waking it up).
1198                  */
1199                 if (unlikely((int64_t)timeout < 0 ||
1200                              (delta > 0 && (uint32_t) (delta >> 50) != 0))) {
1201                         delta = 100 * NSEC_PER_MSEC;
1202                         timeout = guest_now + delta;
1203                 }
1204
1205                 kvm_xen_start_timer(vcpu, timeout, delta);
1206         } else {
1207                 kvm_xen_stop_timer(vcpu);
1208         }
1209
1210         *r = 0;
1211         return true;
1212 }
1213
1214 int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
1215 {
1216         bool longmode;
1217         u64 input, params[6], r = -ENOSYS;
1218         bool handled = false;
1219
1220         input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);
1221
1222         /* Hyper-V hypercalls get bit 31 set in EAX */
1223         if ((input & 0x80000000) &&
1224             kvm_hv_hypercall_enabled(vcpu))
1225                 return kvm_hv_hypercall(vcpu);
1226
1227         longmode = is_64_bit_hypercall(vcpu);
1228         if (!longmode) {
1229                 params[0] = (u32)kvm_rbx_read(vcpu);
1230                 params[1] = (u32)kvm_rcx_read(vcpu);
1231                 params[2] = (u32)kvm_rdx_read(vcpu);
1232                 params[3] = (u32)kvm_rsi_read(vcpu);
1233                 params[4] = (u32)kvm_rdi_read(vcpu);
1234                 params[5] = (u32)kvm_rbp_read(vcpu);
1235         }
1236 #ifdef CONFIG_X86_64
1237         else {
1238                 params[0] = (u64)kvm_rdi_read(vcpu);
1239                 params[1] = (u64)kvm_rsi_read(vcpu);
1240                 params[2] = (u64)kvm_rdx_read(vcpu);
1241                 params[3] = (u64)kvm_r10_read(vcpu);
1242                 params[4] = (u64)kvm_r8_read(vcpu);
1243                 params[5] = (u64)kvm_r9_read(vcpu);
1244         }
1245 #endif
1246         trace_kvm_xen_hypercall(input, params[0], params[1], params[2],
1247                                 params[3], params[4], params[5]);
1248
1249         switch (input) {
1250         case __HYPERVISOR_xen_version:
1251                 if (params[0] == XENVER_version && vcpu->kvm->arch.xen.xen_version) {
1252                         r = vcpu->kvm->arch.xen.xen_version;
1253                         handled = true;
1254                 }
1255                 break;
1256         case __HYPERVISOR_event_channel_op:
1257                 if (params[0] == EVTCHNOP_send)
1258                         handled = kvm_xen_hcall_evtchn_send(vcpu, params[1], &r);
1259                 break;
1260         case __HYPERVISOR_sched_op:
1261                 handled = kvm_xen_hcall_sched_op(vcpu, longmode, params[0],
1262                                                  params[1], &r);
1263                 break;
1264         case __HYPERVISOR_vcpu_op:
1265                 handled = kvm_xen_hcall_vcpu_op(vcpu, longmode, params[0], params[1],
1266                                                 params[2], &r);
1267                 break;
1268         case __HYPERVISOR_set_timer_op: {
1269                 u64 timeout = params[0];
1270                 /* In 32-bit mode, the 64-bit timeout is in two 32-bit params. */
1271                 if (!longmode)
1272                         timeout |= params[1] << 32;
1273                 handled = kvm_xen_hcall_set_timer_op(vcpu, timeout, &r);
1274                 break;
1275         }
1276         default:
1277                 break;
1278         }
1279
1280         if (handled)
1281                 return kvm_xen_hypercall_set_result(vcpu, r);
1282
1283         vcpu->run->exit_reason = KVM_EXIT_XEN;
1284         vcpu->run->xen.type = KVM_EXIT_XEN_HCALL;
1285         vcpu->run->xen.u.hcall.longmode = longmode;
1286         vcpu->run->xen.u.hcall.cpl = static_call(kvm_x86_get_cpl)(vcpu);
1287         vcpu->run->xen.u.hcall.input = input;
1288         vcpu->run->xen.u.hcall.params[0] = params[0];
1289         vcpu->run->xen.u.hcall.params[1] = params[1];
1290         vcpu->run->xen.u.hcall.params[2] = params[2];
1291         vcpu->run->xen.u.hcall.params[3] = params[3];
1292         vcpu->run->xen.u.hcall.params[4] = params[4];
1293         vcpu->run->xen.u.hcall.params[5] = params[5];
1294         vcpu->arch.xen.hypercall_rip = kvm_get_linear_rip(vcpu);
1295         vcpu->arch.complete_userspace_io =
1296                 kvm_xen_hypercall_complete_userspace;
1297
1298         return 0;
1299 }
1300
1301 static inline int max_evtchn_port(struct kvm *kvm)
1302 {
1303         if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode)
1304                 return EVTCHN_2L_NR_CHANNELS;
1305         else
1306                 return COMPAT_EVTCHN_2L_NR_CHANNELS;
1307 }
1308
1309 static void kvm_xen_check_poller(struct kvm_vcpu *vcpu, int port)
1310 {
1311         int poll_evtchn = vcpu->arch.xen.poll_evtchn;
1312
1313         if ((poll_evtchn == port || poll_evtchn == -1) &&
1314             test_and_clear_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.xen.poll_mask)) {
1315                 kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1316                 kvm_vcpu_kick(vcpu);
1317         }
1318 }
1319
1320 /*
1321  * The return value from this function is propagated to kvm_set_irq() API,
1322  * so it returns:
1323  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
1324  *  = 0   Interrupt was coalesced (previous irq is still pending)
1325  *  > 0   Number of CPUs interrupt was delivered to
1326  *
1327  * It is also called directly from kvm_arch_set_irq_inatomic(), where the
1328  * only check on its return value is a comparison with -EWOULDBLOCK'.
1329  */
1330 int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm)
1331 {
1332         struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1333         struct kvm_vcpu *vcpu;
1334         unsigned long *pending_bits, *mask_bits;
1335         unsigned long flags;
1336         int port_word_bit;
1337         bool kick_vcpu = false;
1338         int vcpu_idx, idx, rc;
1339
1340         vcpu_idx = READ_ONCE(xe->vcpu_idx);
1341         if (vcpu_idx >= 0)
1342                 vcpu = kvm_get_vcpu(kvm, vcpu_idx);
1343         else {
1344                 vcpu = kvm_get_vcpu_by_id(kvm, xe->vcpu_id);
1345                 if (!vcpu)
1346                         return -EINVAL;
1347                 WRITE_ONCE(xe->vcpu_idx, kvm_vcpu_get_idx(vcpu));
1348         }
1349
1350         if (!vcpu->arch.xen.vcpu_info_cache.active)
1351                 return -EINVAL;
1352
1353         if (xe->port >= max_evtchn_port(kvm))
1354                 return -EINVAL;
1355
1356         rc = -EWOULDBLOCK;
1357
1358         idx = srcu_read_lock(&kvm->srcu);
1359
1360         read_lock_irqsave(&gpc->lock, flags);
1361         if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, PAGE_SIZE))
1362                 goto out_rcu;
1363
1364         if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1365                 struct shared_info *shinfo = gpc->khva;
1366                 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1367                 mask_bits = (unsigned long *)&shinfo->evtchn_mask;
1368                 port_word_bit = xe->port / 64;
1369         } else {
1370                 struct compat_shared_info *shinfo = gpc->khva;
1371                 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1372                 mask_bits = (unsigned long *)&shinfo->evtchn_mask;
1373                 port_word_bit = xe->port / 32;
1374         }
1375
1376         /*
1377          * If this port wasn't already set, and if it isn't masked, then
1378          * we try to set the corresponding bit in the in-kernel shadow of
1379          * evtchn_pending_sel for the target vCPU. And if *that* wasn't
1380          * already set, then we kick the vCPU in question to write to the
1381          * *real* evtchn_pending_sel in its own guest vcpu_info struct.
1382          */
1383         if (test_and_set_bit(xe->port, pending_bits)) {
1384                 rc = 0; /* It was already raised */
1385         } else if (test_bit(xe->port, mask_bits)) {
1386                 rc = -ENOTCONN; /* Masked */
1387                 kvm_xen_check_poller(vcpu, xe->port);
1388         } else {
1389                 rc = 1; /* Delivered to the bitmap in shared_info. */
1390                 /* Now switch to the vCPU's vcpu_info to set the index and pending_sel */
1391                 read_unlock_irqrestore(&gpc->lock, flags);
1392                 gpc = &vcpu->arch.xen.vcpu_info_cache;
1393
1394                 read_lock_irqsave(&gpc->lock, flags);
1395                 if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, sizeof(struct vcpu_info))) {
1396                         /*
1397                          * Could not access the vcpu_info. Set the bit in-kernel
1398                          * and prod the vCPU to deliver it for itself.
1399                          */
1400                         if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel))
1401                                 kick_vcpu = true;
1402                         goto out_rcu;
1403                 }
1404
1405                 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1406                         struct vcpu_info *vcpu_info = gpc->khva;
1407                         if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) {
1408                                 WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
1409                                 kick_vcpu = true;
1410                         }
1411                 } else {
1412                         struct compat_vcpu_info *vcpu_info = gpc->khva;
1413                         if (!test_and_set_bit(port_word_bit,
1414                                               (unsigned long *)&vcpu_info->evtchn_pending_sel)) {
1415                                 WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
1416                                 kick_vcpu = true;
1417                         }
1418                 }
1419
1420                 /* For the per-vCPU lapic vector, deliver it as MSI. */
1421                 if (kick_vcpu && vcpu->arch.xen.upcall_vector) {
1422                         kvm_xen_inject_vcpu_vector(vcpu);
1423                         kick_vcpu = false;
1424                 }
1425         }
1426
1427  out_rcu:
1428         read_unlock_irqrestore(&gpc->lock, flags);
1429         srcu_read_unlock(&kvm->srcu, idx);
1430
1431         if (kick_vcpu) {
1432                 kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1433                 kvm_vcpu_kick(vcpu);
1434         }
1435
1436         return rc;
1437 }
1438
1439 static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm)
1440 {
1441         bool mm_borrowed = false;
1442         int rc;
1443
1444         rc = kvm_xen_set_evtchn_fast(xe, kvm);
1445         if (rc != -EWOULDBLOCK)
1446                 return rc;
1447
1448         if (current->mm != kvm->mm) {
1449                 /*
1450                  * If not on a thread which already belongs to this KVM,
1451                  * we'd better be in the irqfd workqueue.
1452                  */
1453                 if (WARN_ON_ONCE(current->mm))
1454                         return -EINVAL;
1455
1456                 kthread_use_mm(kvm->mm);
1457                 mm_borrowed = true;
1458         }
1459
1460         /*
1461          * For the irqfd workqueue, using the main kvm->lock mutex is
1462          * fine since this function is invoked from kvm_set_irq() with
1463          * no other lock held, no srcu. In future if it will be called
1464          * directly from a vCPU thread (e.g. on hypercall for an IPI)
1465          * then it may need to switch to using a leaf-node mutex for
1466          * serializing the shared_info mapping.
1467          */
1468         mutex_lock(&kvm->lock);
1469
1470         /*
1471          * It is theoretically possible for the page to be unmapped
1472          * and the MMU notifier to invalidate the shared_info before
1473          * we even get to use it. In that case, this looks like an
1474          * infinite loop. It was tempting to do it via the userspace
1475          * HVA instead... but that just *hides* the fact that it's
1476          * an infinite loop, because if a fault occurs and it waits
1477          * for the page to come back, it can *still* immediately
1478          * fault and have to wait again, repeatedly.
1479          *
1480          * Conversely, the page could also have been reinstated by
1481          * another thread before we even obtain the mutex above, so
1482          * check again *first* before remapping it.
1483          */
1484         do {
1485                 struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1486                 int idx;
1487
1488                 rc = kvm_xen_set_evtchn_fast(xe, kvm);
1489                 if (rc != -EWOULDBLOCK)
1490                         break;
1491
1492                 idx = srcu_read_lock(&kvm->srcu);
1493                 rc = kvm_gfn_to_pfn_cache_refresh(kvm, gpc, gpc->gpa, PAGE_SIZE);
1494                 srcu_read_unlock(&kvm->srcu, idx);
1495         } while(!rc);
1496
1497         mutex_unlock(&kvm->lock);
1498
1499         if (mm_borrowed)
1500                 kthread_unuse_mm(kvm->mm);
1501
1502         return rc;
1503 }
1504
1505 /* This is the version called from kvm_set_irq() as the .set function */
1506 static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
1507                          int irq_source_id, int level, bool line_status)
1508 {
1509         if (!level)
1510                 return -EINVAL;
1511
1512         return kvm_xen_set_evtchn(&e->xen_evtchn, kvm);
1513 }
1514
1515 /*
1516  * Set up an event channel interrupt from the KVM IRQ routing table.
1517  * Used for e.g. PIRQ from passed through physical devices.
1518  */
1519 int kvm_xen_setup_evtchn(struct kvm *kvm,
1520                          struct kvm_kernel_irq_routing_entry *e,
1521                          const struct kvm_irq_routing_entry *ue)
1522
1523 {
1524         struct kvm_vcpu *vcpu;
1525
1526         if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm))
1527                 return -EINVAL;
1528
1529         /* We only support 2 level event channels for now */
1530         if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1531                 return -EINVAL;
1532
1533         /*
1534          * Xen gives us interesting mappings from vCPU index to APIC ID,
1535          * which means kvm_get_vcpu_by_id() has to iterate over all vCPUs
1536          * to find it. Do that once at setup time, instead of every time.
1537          * But beware that on live update / live migration, the routing
1538          * table might be reinstated before the vCPU threads have finished
1539          * recreating their vCPUs.
1540          */
1541         vcpu = kvm_get_vcpu_by_id(kvm, ue->u.xen_evtchn.vcpu);
1542         if (vcpu)
1543                 e->xen_evtchn.vcpu_idx = kvm_vcpu_get_idx(vcpu);
1544         else
1545                 e->xen_evtchn.vcpu_idx = -1;
1546
1547         e->xen_evtchn.port = ue->u.xen_evtchn.port;
1548         e->xen_evtchn.vcpu_id = ue->u.xen_evtchn.vcpu;
1549         e->xen_evtchn.priority = ue->u.xen_evtchn.priority;
1550         e->set = evtchn_set_fn;
1551
1552         return 0;
1553 }
1554
1555 /*
1556  * Explicit event sending from userspace with KVM_XEN_HVM_EVTCHN_SEND ioctl.
1557  */
1558 int kvm_xen_hvm_evtchn_send(struct kvm *kvm, struct kvm_irq_routing_xen_evtchn *uxe)
1559 {
1560         struct kvm_xen_evtchn e;
1561         int ret;
1562
1563         if (!uxe->port || uxe->port >= max_evtchn_port(kvm))
1564                 return -EINVAL;
1565
1566         /* We only support 2 level event channels for now */
1567         if (uxe->priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1568                 return -EINVAL;
1569
1570         e.port = uxe->port;
1571         e.vcpu_id = uxe->vcpu;
1572         e.vcpu_idx = -1;
1573         e.priority = uxe->priority;
1574
1575         ret = kvm_xen_set_evtchn(&e, kvm);
1576
1577         /*
1578          * None of that 'return 1 if it actually got delivered' nonsense.
1579          * We don't care if it was masked (-ENOTCONN) either.
1580          */
1581         if (ret > 0 || ret == -ENOTCONN)
1582                 ret = 0;
1583
1584         return ret;
1585 }
1586
1587 /*
1588  * Support for *outbound* event channel events via the EVTCHNOP_send hypercall.
1589  */
1590 struct evtchnfd {
1591         u32 send_port;
1592         u32 type;
1593         union {
1594                 struct kvm_xen_evtchn port;
1595                 struct {
1596                         u32 port; /* zero */
1597                         struct eventfd_ctx *ctx;
1598                 } eventfd;
1599         } deliver;
1600 };
1601
1602 /*
1603  * Update target vCPU or priority for a registered sending channel.
1604  */
1605 static int kvm_xen_eventfd_update(struct kvm *kvm,
1606                                   struct kvm_xen_hvm_attr *data)
1607 {
1608         u32 port = data->u.evtchn.send_port;
1609         struct evtchnfd *evtchnfd;
1610
1611         if (!port || port >= max_evtchn_port(kvm))
1612                 return -EINVAL;
1613
1614         mutex_lock(&kvm->lock);
1615         evtchnfd = idr_find(&kvm->arch.xen.evtchn_ports, port);
1616         mutex_unlock(&kvm->lock);
1617
1618         if (!evtchnfd)
1619                 return -ENOENT;
1620
1621         /* For an UPDATE, nothing may change except the priority/vcpu */
1622         if (evtchnfd->type != data->u.evtchn.type)
1623                 return -EINVAL;
1624
1625         /*
1626          * Port cannot change, and if it's zero that was an eventfd
1627          * which can't be changed either.
1628          */
1629         if (!evtchnfd->deliver.port.port ||
1630             evtchnfd->deliver.port.port != data->u.evtchn.deliver.port.port)
1631                 return -EINVAL;
1632
1633         /* We only support 2 level event channels for now */
1634         if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1635                 return -EINVAL;
1636
1637         mutex_lock(&kvm->lock);
1638         evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
1639         if (evtchnfd->deliver.port.vcpu_id != data->u.evtchn.deliver.port.vcpu) {
1640                 evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
1641                 evtchnfd->deliver.port.vcpu_idx = -1;
1642         }
1643         mutex_unlock(&kvm->lock);
1644         return 0;
1645 }
1646
1647 /*
1648  * Configure the target (eventfd or local port delivery) for sending on
1649  * a given event channel.
1650  */
1651 static int kvm_xen_eventfd_assign(struct kvm *kvm,
1652                                   struct kvm_xen_hvm_attr *data)
1653 {
1654         u32 port = data->u.evtchn.send_port;
1655         struct eventfd_ctx *eventfd = NULL;
1656         struct evtchnfd *evtchnfd = NULL;
1657         int ret = -EINVAL;
1658
1659         if (!port || port >= max_evtchn_port(kvm))
1660                 return -EINVAL;
1661
1662         evtchnfd = kzalloc(sizeof(struct evtchnfd), GFP_KERNEL);
1663         if (!evtchnfd)
1664                 return -ENOMEM;
1665
1666         switch(data->u.evtchn.type) {
1667         case EVTCHNSTAT_ipi:
1668                 /* IPI  must map back to the same port# */
1669                 if (data->u.evtchn.deliver.port.port != data->u.evtchn.send_port)
1670                         goto out; /* -EINVAL */
1671                 break;
1672
1673         case EVTCHNSTAT_interdomain:
1674                 if (data->u.evtchn.deliver.port.port) {
1675                         if (data->u.evtchn.deliver.port.port >= max_evtchn_port(kvm))
1676                                 goto out; /* -EINVAL */
1677                 } else {
1678                         eventfd = eventfd_ctx_fdget(data->u.evtchn.deliver.eventfd.fd);
1679                         if (IS_ERR(eventfd)) {
1680                                 ret = PTR_ERR(eventfd);
1681                                 goto out;
1682                         }
1683                 }
1684                 break;
1685
1686         case EVTCHNSTAT_virq:
1687         case EVTCHNSTAT_closed:
1688         case EVTCHNSTAT_unbound:
1689         case EVTCHNSTAT_pirq:
1690         default: /* Unknown event channel type */
1691                 goto out; /* -EINVAL */
1692         }
1693
1694         evtchnfd->send_port = data->u.evtchn.send_port;
1695         evtchnfd->type = data->u.evtchn.type;
1696         if (eventfd) {
1697                 evtchnfd->deliver.eventfd.ctx = eventfd;
1698         } else {
1699                 /* We only support 2 level event channels for now */
1700                 if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1701                         goto out; /* -EINVAL; */
1702
1703                 evtchnfd->deliver.port.port = data->u.evtchn.deliver.port.port;
1704                 evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
1705                 evtchnfd->deliver.port.vcpu_idx = -1;
1706                 evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
1707         }
1708
1709         mutex_lock(&kvm->lock);
1710         ret = idr_alloc(&kvm->arch.xen.evtchn_ports, evtchnfd, port, port + 1,
1711                         GFP_KERNEL);
1712         mutex_unlock(&kvm->lock);
1713         if (ret >= 0)
1714                 return 0;
1715
1716         if (ret == -ENOSPC)
1717                 ret = -EEXIST;
1718 out:
1719         if (eventfd)
1720                 eventfd_ctx_put(eventfd);
1721         kfree(evtchnfd);
1722         return ret;
1723 }
1724
1725 static int kvm_xen_eventfd_deassign(struct kvm *kvm, u32 port)
1726 {
1727         struct evtchnfd *evtchnfd;
1728
1729         mutex_lock(&kvm->lock);
1730         evtchnfd = idr_remove(&kvm->arch.xen.evtchn_ports, port);
1731         mutex_unlock(&kvm->lock);
1732
1733         if (!evtchnfd)
1734                 return -ENOENT;
1735
1736         if (kvm)
1737                 synchronize_srcu(&kvm->srcu);
1738         if (!evtchnfd->deliver.port.port)
1739                 eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
1740         kfree(evtchnfd);
1741         return 0;
1742 }
1743
1744 static int kvm_xen_eventfd_reset(struct kvm *kvm)
1745 {
1746         struct evtchnfd *evtchnfd;
1747         int i;
1748
1749         mutex_lock(&kvm->lock);
1750         idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
1751                 idr_remove(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port);
1752                 synchronize_srcu(&kvm->srcu);
1753                 if (!evtchnfd->deliver.port.port)
1754                         eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
1755                 kfree(evtchnfd);
1756         }
1757         mutex_unlock(&kvm->lock);
1758
1759         return 0;
1760 }
1761
1762 static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
1763 {
1764         u32 port = data->u.evtchn.send_port;
1765
1766         if (data->u.evtchn.flags == KVM_XEN_EVTCHN_RESET)
1767                 return kvm_xen_eventfd_reset(kvm);
1768
1769         if (!port || port >= max_evtchn_port(kvm))
1770                 return -EINVAL;
1771
1772         if (data->u.evtchn.flags == KVM_XEN_EVTCHN_DEASSIGN)
1773                 return kvm_xen_eventfd_deassign(kvm, port);
1774         if (data->u.evtchn.flags == KVM_XEN_EVTCHN_UPDATE)
1775                 return kvm_xen_eventfd_update(kvm, data);
1776         if (data->u.evtchn.flags)
1777                 return -EINVAL;
1778
1779         return kvm_xen_eventfd_assign(kvm, data);
1780 }
1781
1782 static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
1783 {
1784         struct evtchnfd *evtchnfd;
1785         struct evtchn_send send;
1786         gpa_t gpa;
1787         int idx;
1788
1789         idx = srcu_read_lock(&vcpu->kvm->srcu);
1790         gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
1791         srcu_read_unlock(&vcpu->kvm->srcu, idx);
1792
1793         if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &send, sizeof(send))) {
1794                 *r = -EFAULT;
1795                 return true;
1796         }
1797
1798         /* The evtchn_ports idr is protected by vcpu->kvm->srcu */
1799         evtchnfd = idr_find(&vcpu->kvm->arch.xen.evtchn_ports, send.port);
1800         if (!evtchnfd)
1801                 return false;
1802
1803         if (evtchnfd->deliver.port.port) {
1804                 int ret = kvm_xen_set_evtchn(&evtchnfd->deliver.port, vcpu->kvm);
1805                 if (ret < 0 && ret != -ENOTCONN)
1806                         return false;
1807         } else {
1808                 eventfd_signal(evtchnfd->deliver.eventfd.ctx, 1);
1809         }
1810
1811         *r = 0;
1812         return true;
1813 }
1814
1815 void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu)
1816 {
1817         vcpu->arch.xen.vcpu_id = vcpu->vcpu_idx;
1818         vcpu->arch.xen.poll_evtchn = 0;
1819         timer_setup(&vcpu->arch.xen.poll_timer, cancel_evtchn_poll, 0);
1820 }
1821
1822 void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
1823 {
1824         if (kvm_xen_timer_enabled(vcpu))
1825                 kvm_xen_stop_timer(vcpu);
1826
1827         kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
1828                                      &vcpu->arch.xen.runstate_cache);
1829         kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
1830                                      &vcpu->arch.xen.vcpu_info_cache);
1831         kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
1832                                      &vcpu->arch.xen.vcpu_time_info_cache);
1833         del_timer_sync(&vcpu->arch.xen.poll_timer);
1834 }
1835
1836 void kvm_xen_init_vm(struct kvm *kvm)
1837 {
1838         idr_init(&kvm->arch.xen.evtchn_ports);
1839 }
1840
1841 void kvm_xen_destroy_vm(struct kvm *kvm)
1842 {
1843         struct evtchnfd *evtchnfd;
1844         int i;
1845
1846         kvm_gfn_to_pfn_cache_destroy(kvm, &kvm->arch.xen.shinfo_cache);
1847
1848         idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
1849                 if (!evtchnfd->deliver.port.port)
1850                         eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
1851                 kfree(evtchnfd);
1852         }
1853         idr_destroy(&kvm->arch.xen.evtchn_ports);
1854
1855         if (kvm->arch.xen_hvm_config.msr)
1856                 static_branch_slow_dec_deferred(&kvm_xen_enabled);
1857 }