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
kvm_xen_shared_info_init(struct kvm * kvm,gfn_t gfn)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_gpc_deactivate(kvm, gpc);
46 goto out;
47 }
48
49 do {
50 ret = kvm_gpc_activate(kvm, gpc, NULL, KVM_HOST_USES_PFN, gpa,
51 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
kvm_xen_inject_timer_irqs(struct kvm_vcpu * vcpu)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
xen_timer_callback(struct hrtimer * timer)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
kvm_xen_start_timer(struct kvm_vcpu * vcpu,u64 guest_abs,s64 delta_ns)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
kvm_xen_stop_timer(struct kvm_vcpu * vcpu)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
kvm_xen_init_timer(struct kvm_vcpu * vcpu)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
kvm_xen_update_runstate(struct kvm_vcpu * v,int state)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
kvm_xen_update_runstate_guest(struct kvm_vcpu * v,int state)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
kvm_xen_inject_vcpu_vector(struct kvm_vcpu * v)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 */
kvm_xen_inject_pending_events(struct kvm_vcpu * v)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
__kvm_xen_has_interrupt(struct kvm_vcpu * v)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
kvm_xen_hvm_set_attr(struct kvm * kvm,struct kvm_xen_hvm_attr * data)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
kvm_xen_hvm_get_attr(struct kvm * kvm,struct kvm_xen_hvm_attr * data)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
kvm_xen_vcpu_set_attr(struct kvm_vcpu * vcpu,struct kvm_xen_vcpu_attr * data)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_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache);
558 r = 0;
559 break;
560 }
561
562 r = kvm_gpc_activate(vcpu->kvm,
563 &vcpu->arch.xen.vcpu_info_cache, NULL,
564 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_gpc_deactivate(vcpu->kvm,
574 &vcpu->arch.xen.vcpu_time_info_cache);
575 r = 0;
576 break;
577 }
578
579 r = kvm_gpc_activate(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_gpc_deactivate(vcpu->kvm,
594 &vcpu->arch.xen.runstate_cache);
595 r = 0;
596 break;
597 }
598
599 r = kvm_gpc_activate(vcpu->kvm, &vcpu->arch.xen.runstate_cache,
600 NULL, KVM_HOST_USES_PFN, data->u.gpa,
601 sizeof(struct vcpu_runstate_info));
602 break;
603
604 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
605 if (!sched_info_on()) {
606 r = -EOPNOTSUPP;
607 break;
608 }
609 if (data->u.runstate.state > RUNSTATE_offline) {
610 r = -EINVAL;
611 break;
612 }
613
614 kvm_xen_update_runstate(vcpu, data->u.runstate.state);
615 r = 0;
616 break;
617
618 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
619 if (!sched_info_on()) {
620 r = -EOPNOTSUPP;
621 break;
622 }
623 if (data->u.runstate.state > RUNSTATE_offline) {
624 r = -EINVAL;
625 break;
626 }
627 if (data->u.runstate.state_entry_time !=
628 (data->u.runstate.time_running +
629 data->u.runstate.time_runnable +
630 data->u.runstate.time_blocked +
631 data->u.runstate.time_offline)) {
632 r = -EINVAL;
633 break;
634 }
635 if (get_kvmclock_ns(vcpu->kvm) <
636 data->u.runstate.state_entry_time) {
637 r = -EINVAL;
638 break;
639 }
640
641 vcpu->arch.xen.current_runstate = data->u.runstate.state;
642 vcpu->arch.xen.runstate_entry_time =
643 data->u.runstate.state_entry_time;
644 vcpu->arch.xen.runstate_times[RUNSTATE_running] =
645 data->u.runstate.time_running;
646 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] =
647 data->u.runstate.time_runnable;
648 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] =
649 data->u.runstate.time_blocked;
650 vcpu->arch.xen.runstate_times[RUNSTATE_offline] =
651 data->u.runstate.time_offline;
652 vcpu->arch.xen.last_steal = current->sched_info.run_delay;
653 r = 0;
654 break;
655
656 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
657 if (!sched_info_on()) {
658 r = -EOPNOTSUPP;
659 break;
660 }
661 if (data->u.runstate.state > RUNSTATE_offline &&
662 data->u.runstate.state != (u64)-1) {
663 r = -EINVAL;
664 break;
665 }
666 /* The adjustment must add up */
667 if (data->u.runstate.state_entry_time !=
668 (data->u.runstate.time_running +
669 data->u.runstate.time_runnable +
670 data->u.runstate.time_blocked +
671 data->u.runstate.time_offline)) {
672 r = -EINVAL;
673 break;
674 }
675
676 if (get_kvmclock_ns(vcpu->kvm) <
677 (vcpu->arch.xen.runstate_entry_time +
678 data->u.runstate.state_entry_time)) {
679 r = -EINVAL;
680 break;
681 }
682
683 vcpu->arch.xen.runstate_entry_time +=
684 data->u.runstate.state_entry_time;
685 vcpu->arch.xen.runstate_times[RUNSTATE_running] +=
686 data->u.runstate.time_running;
687 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] +=
688 data->u.runstate.time_runnable;
689 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] +=
690 data->u.runstate.time_blocked;
691 vcpu->arch.xen.runstate_times[RUNSTATE_offline] +=
692 data->u.runstate.time_offline;
693
694 if (data->u.runstate.state <= RUNSTATE_offline)
695 kvm_xen_update_runstate(vcpu, data->u.runstate.state);
696 r = 0;
697 break;
698
699 case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
700 if (data->u.vcpu_id >= KVM_MAX_VCPUS)
701 r = -EINVAL;
702 else {
703 vcpu->arch.xen.vcpu_id = data->u.vcpu_id;
704 r = 0;
705 }
706 break;
707
708 case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
709 if (data->u.timer.port &&
710 data->u.timer.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) {
711 r = -EINVAL;
712 break;
713 }
714
715 if (!vcpu->arch.xen.timer.function)
716 kvm_xen_init_timer(vcpu);
717
718 /* Stop the timer (if it's running) before changing the vector */
719 kvm_xen_stop_timer(vcpu);
720 vcpu->arch.xen.timer_virq = data->u.timer.port;
721
722 /* Start the timer if the new value has a valid vector+expiry. */
723 if (data->u.timer.port && data->u.timer.expires_ns)
724 kvm_xen_start_timer(vcpu, data->u.timer.expires_ns,
725 data->u.timer.expires_ns -
726 get_kvmclock_ns(vcpu->kvm));
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
kvm_xen_vcpu_get_attr(struct kvm_vcpu * vcpu,struct kvm_xen_vcpu_attr * data)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
kvm_xen_write_hypercall_page(struct kvm_vcpu * vcpu,u64 data)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
kvm_xen_hvm_config(struct kvm * kvm,struct kvm_xen_hvm_config * xhc)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
kvm_xen_hypercall_set_result(struct kvm_vcpu * vcpu,u64 result)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
kvm_xen_hypercall_complete_userspace(struct kvm_vcpu * vcpu)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
max_evtchn_port(struct kvm * kvm)957 static inline int max_evtchn_port(struct kvm *kvm)
958 {
959 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode)
960 return EVTCHN_2L_NR_CHANNELS;
961 else
962 return COMPAT_EVTCHN_2L_NR_CHANNELS;
963 }
964
wait_pending_event(struct kvm_vcpu * vcpu,int nr_ports,evtchn_port_t * ports)965 static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports,
966 evtchn_port_t *ports)
967 {
968 struct kvm *kvm = vcpu->kvm;
969 struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
970 unsigned long *pending_bits;
971 unsigned long flags;
972 bool ret = true;
973 int idx, i;
974
975 read_lock_irqsave(&gpc->lock, flags);
976 idx = srcu_read_lock(&kvm->srcu);
977 if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, PAGE_SIZE))
978 goto out_rcu;
979
980 ret = false;
981 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
982 struct shared_info *shinfo = gpc->khva;
983 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
984 } else {
985 struct compat_shared_info *shinfo = gpc->khva;
986 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
987 }
988
989 for (i = 0; i < nr_ports; i++) {
990 if (test_bit(ports[i], pending_bits)) {
991 ret = true;
992 break;
993 }
994 }
995
996 out_rcu:
997 srcu_read_unlock(&kvm->srcu, idx);
998 read_unlock_irqrestore(&gpc->lock, flags);
999
1000 return ret;
1001 }
1002
kvm_xen_schedop_poll(struct kvm_vcpu * vcpu,bool longmode,u64 param,u64 * r)1003 static bool kvm_xen_schedop_poll(struct kvm_vcpu *vcpu, bool longmode,
1004 u64 param, u64 *r)
1005 {
1006 int idx, i;
1007 struct sched_poll sched_poll;
1008 evtchn_port_t port, *ports;
1009 gpa_t gpa;
1010
1011 if (!longmode || !lapic_in_kernel(vcpu) ||
1012 !(vcpu->kvm->arch.xen_hvm_config.flags & KVM_XEN_HVM_CONFIG_EVTCHN_SEND))
1013 return false;
1014
1015 idx = srcu_read_lock(&vcpu->kvm->srcu);
1016 gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
1017 srcu_read_unlock(&vcpu->kvm->srcu, idx);
1018
1019 if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &sched_poll,
1020 sizeof(sched_poll))) {
1021 *r = -EFAULT;
1022 return true;
1023 }
1024
1025 if (unlikely(sched_poll.nr_ports > 1)) {
1026 /* Xen (unofficially) limits number of pollers to 128 */
1027 if (sched_poll.nr_ports > 128) {
1028 *r = -EINVAL;
1029 return true;
1030 }
1031
1032 ports = kmalloc_array(sched_poll.nr_ports,
1033 sizeof(*ports), GFP_KERNEL);
1034 if (!ports) {
1035 *r = -ENOMEM;
1036 return true;
1037 }
1038 } else
1039 ports = &port;
1040
1041 for (i = 0; i < sched_poll.nr_ports; i++) {
1042 idx = srcu_read_lock(&vcpu->kvm->srcu);
1043 gpa = kvm_mmu_gva_to_gpa_system(vcpu,
1044 (gva_t)(sched_poll.ports + i),
1045 NULL);
1046 srcu_read_unlock(&vcpu->kvm->srcu, idx);
1047
1048 if (!gpa || kvm_vcpu_read_guest(vcpu, gpa,
1049 &ports[i], sizeof(port))) {
1050 *r = -EFAULT;
1051 goto out;
1052 }
1053 if (ports[i] >= max_evtchn_port(vcpu->kvm)) {
1054 *r = -EINVAL;
1055 goto out;
1056 }
1057 }
1058
1059 if (sched_poll.nr_ports == 1)
1060 vcpu->arch.xen.poll_evtchn = port;
1061 else
1062 vcpu->arch.xen.poll_evtchn = -1;
1063
1064 set_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask);
1065
1066 if (!wait_pending_event(vcpu, sched_poll.nr_ports, ports)) {
1067 vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
1068
1069 if (sched_poll.timeout)
1070 mod_timer(&vcpu->arch.xen.poll_timer,
1071 jiffies + nsecs_to_jiffies(sched_poll.timeout));
1072
1073 kvm_vcpu_halt(vcpu);
1074
1075 if (sched_poll.timeout)
1076 del_timer(&vcpu->arch.xen.poll_timer);
1077
1078 vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
1079 }
1080
1081 vcpu->arch.xen.poll_evtchn = 0;
1082 *r = 0;
1083 out:
1084 /* Really, this is only needed in case of timeout */
1085 clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask);
1086
1087 if (unlikely(sched_poll.nr_ports > 1))
1088 kfree(ports);
1089 return true;
1090 }
1091
cancel_evtchn_poll(struct timer_list * t)1092 static void cancel_evtchn_poll(struct timer_list *t)
1093 {
1094 struct kvm_vcpu *vcpu = from_timer(vcpu, t, arch.xen.poll_timer);
1095
1096 kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1097 kvm_vcpu_kick(vcpu);
1098 }
1099
kvm_xen_hcall_sched_op(struct kvm_vcpu * vcpu,bool longmode,int cmd,u64 param,u64 * r)1100 static bool kvm_xen_hcall_sched_op(struct kvm_vcpu *vcpu, bool longmode,
1101 int cmd, u64 param, u64 *r)
1102 {
1103 switch (cmd) {
1104 case SCHEDOP_poll:
1105 if (kvm_xen_schedop_poll(vcpu, longmode, param, r))
1106 return true;
1107 fallthrough;
1108 case SCHEDOP_yield:
1109 kvm_vcpu_on_spin(vcpu, true);
1110 *r = 0;
1111 return true;
1112 default:
1113 break;
1114 }
1115
1116 return false;
1117 }
1118
1119 struct compat_vcpu_set_singleshot_timer {
1120 uint64_t timeout_abs_ns;
1121 uint32_t flags;
1122 } __attribute__((packed));
1123
kvm_xen_hcall_vcpu_op(struct kvm_vcpu * vcpu,bool longmode,int cmd,int vcpu_id,u64 param,u64 * r)1124 static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
1125 int vcpu_id, u64 param, u64 *r)
1126 {
1127 struct vcpu_set_singleshot_timer oneshot;
1128 s64 delta;
1129 gpa_t gpa;
1130 int idx;
1131
1132 if (!kvm_xen_timer_enabled(vcpu))
1133 return false;
1134
1135 switch (cmd) {
1136 case VCPUOP_set_singleshot_timer:
1137 if (vcpu->arch.xen.vcpu_id != vcpu_id) {
1138 *r = -EINVAL;
1139 return true;
1140 }
1141 idx = srcu_read_lock(&vcpu->kvm->srcu);
1142 gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
1143 srcu_read_unlock(&vcpu->kvm->srcu, idx);
1144
1145 /*
1146 * The only difference for 32-bit compat is the 4 bytes of
1147 * padding after the interesting part of the structure. So
1148 * for a faithful emulation of Xen we have to *try* to copy
1149 * the padding and return -EFAULT if we can't. Otherwise we
1150 * might as well just have copied the 12-byte 32-bit struct.
1151 */
1152 BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
1153 offsetof(struct vcpu_set_singleshot_timer, timeout_abs_ns));
1154 BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
1155 sizeof_field(struct vcpu_set_singleshot_timer, timeout_abs_ns));
1156 BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, flags) !=
1157 offsetof(struct vcpu_set_singleshot_timer, flags));
1158 BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, flags) !=
1159 sizeof_field(struct vcpu_set_singleshot_timer, flags));
1160
1161 if (!gpa ||
1162 kvm_vcpu_read_guest(vcpu, gpa, &oneshot, longmode ? sizeof(oneshot) :
1163 sizeof(struct compat_vcpu_set_singleshot_timer))) {
1164 *r = -EFAULT;
1165 return true;
1166 }
1167
1168 delta = oneshot.timeout_abs_ns - get_kvmclock_ns(vcpu->kvm);
1169 if ((oneshot.flags & VCPU_SSHOTTMR_future) && delta < 0) {
1170 *r = -ETIME;
1171 return true;
1172 }
1173
1174 kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, delta);
1175 *r = 0;
1176 return true;
1177
1178 case VCPUOP_stop_singleshot_timer:
1179 if (vcpu->arch.xen.vcpu_id != vcpu_id) {
1180 *r = -EINVAL;
1181 return true;
1182 }
1183 kvm_xen_stop_timer(vcpu);
1184 *r = 0;
1185 return true;
1186 }
1187
1188 return false;
1189 }
1190
kvm_xen_hcall_set_timer_op(struct kvm_vcpu * vcpu,uint64_t timeout,u64 * r)1191 static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout,
1192 u64 *r)
1193 {
1194 if (!kvm_xen_timer_enabled(vcpu))
1195 return false;
1196
1197 if (timeout) {
1198 uint64_t guest_now = get_kvmclock_ns(vcpu->kvm);
1199 int64_t delta = timeout - guest_now;
1200
1201 /* Xen has a 'Linux workaround' in do_set_timer_op() which
1202 * checks for negative absolute timeout values (caused by
1203 * integer overflow), and for values about 13 days in the
1204 * future (2^50ns) which would be caused by jiffies
1205 * overflow. For those cases, it sets the timeout 100ms in
1206 * the future (not *too* soon, since if a guest really did
1207 * set a long timeout on purpose we don't want to keep
1208 * churning CPU time by waking it up).
1209 */
1210 if (unlikely((int64_t)timeout < 0 ||
1211 (delta > 0 && (uint32_t) (delta >> 50) != 0))) {
1212 delta = 100 * NSEC_PER_MSEC;
1213 timeout = guest_now + delta;
1214 }
1215
1216 kvm_xen_start_timer(vcpu, timeout, delta);
1217 } else {
1218 kvm_xen_stop_timer(vcpu);
1219 }
1220
1221 *r = 0;
1222 return true;
1223 }
1224
kvm_xen_hypercall(struct kvm_vcpu * vcpu)1225 int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
1226 {
1227 bool longmode;
1228 u64 input, params[6], r = -ENOSYS;
1229 bool handled = false;
1230 u8 cpl;
1231
1232 input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);
1233
1234 /* Hyper-V hypercalls get bit 31 set in EAX */
1235 if ((input & 0x80000000) &&
1236 kvm_hv_hypercall_enabled(vcpu))
1237 return kvm_hv_hypercall(vcpu);
1238
1239 longmode = is_64_bit_hypercall(vcpu);
1240 if (!longmode) {
1241 params[0] = (u32)kvm_rbx_read(vcpu);
1242 params[1] = (u32)kvm_rcx_read(vcpu);
1243 params[2] = (u32)kvm_rdx_read(vcpu);
1244 params[3] = (u32)kvm_rsi_read(vcpu);
1245 params[4] = (u32)kvm_rdi_read(vcpu);
1246 params[5] = (u32)kvm_rbp_read(vcpu);
1247 }
1248 #ifdef CONFIG_X86_64
1249 else {
1250 params[0] = (u64)kvm_rdi_read(vcpu);
1251 params[1] = (u64)kvm_rsi_read(vcpu);
1252 params[2] = (u64)kvm_rdx_read(vcpu);
1253 params[3] = (u64)kvm_r10_read(vcpu);
1254 params[4] = (u64)kvm_r8_read(vcpu);
1255 params[5] = (u64)kvm_r9_read(vcpu);
1256 }
1257 #endif
1258 cpl = static_call(kvm_x86_get_cpl)(vcpu);
1259 trace_kvm_xen_hypercall(input, params[0], params[1], params[2],
1260 params[3], params[4], params[5]);
1261
1262 /*
1263 * Only allow hypercall acceleration for CPL0. The rare hypercalls that
1264 * are permitted in guest userspace can be handled by the VMM.
1265 */
1266 if (unlikely(cpl > 0))
1267 goto handle_in_userspace;
1268
1269 switch (input) {
1270 case __HYPERVISOR_xen_version:
1271 if (params[0] == XENVER_version && vcpu->kvm->arch.xen.xen_version) {
1272 r = vcpu->kvm->arch.xen.xen_version;
1273 handled = true;
1274 }
1275 break;
1276 case __HYPERVISOR_event_channel_op:
1277 if (params[0] == EVTCHNOP_send)
1278 handled = kvm_xen_hcall_evtchn_send(vcpu, params[1], &r);
1279 break;
1280 case __HYPERVISOR_sched_op:
1281 handled = kvm_xen_hcall_sched_op(vcpu, longmode, params[0],
1282 params[1], &r);
1283 break;
1284 case __HYPERVISOR_vcpu_op:
1285 handled = kvm_xen_hcall_vcpu_op(vcpu, longmode, params[0], params[1],
1286 params[2], &r);
1287 break;
1288 case __HYPERVISOR_set_timer_op: {
1289 u64 timeout = params[0];
1290 /* In 32-bit mode, the 64-bit timeout is in two 32-bit params. */
1291 if (!longmode)
1292 timeout |= params[1] << 32;
1293 handled = kvm_xen_hcall_set_timer_op(vcpu, timeout, &r);
1294 break;
1295 }
1296 default:
1297 break;
1298 }
1299
1300 if (handled)
1301 return kvm_xen_hypercall_set_result(vcpu, r);
1302
1303 handle_in_userspace:
1304 vcpu->run->exit_reason = KVM_EXIT_XEN;
1305 vcpu->run->xen.type = KVM_EXIT_XEN_HCALL;
1306 vcpu->run->xen.u.hcall.longmode = longmode;
1307 vcpu->run->xen.u.hcall.cpl = cpl;
1308 vcpu->run->xen.u.hcall.input = input;
1309 vcpu->run->xen.u.hcall.params[0] = params[0];
1310 vcpu->run->xen.u.hcall.params[1] = params[1];
1311 vcpu->run->xen.u.hcall.params[2] = params[2];
1312 vcpu->run->xen.u.hcall.params[3] = params[3];
1313 vcpu->run->xen.u.hcall.params[4] = params[4];
1314 vcpu->run->xen.u.hcall.params[5] = params[5];
1315 vcpu->arch.xen.hypercall_rip = kvm_get_linear_rip(vcpu);
1316 vcpu->arch.complete_userspace_io =
1317 kvm_xen_hypercall_complete_userspace;
1318
1319 return 0;
1320 }
1321
kvm_xen_check_poller(struct kvm_vcpu * vcpu,int port)1322 static void kvm_xen_check_poller(struct kvm_vcpu *vcpu, int port)
1323 {
1324 int poll_evtchn = vcpu->arch.xen.poll_evtchn;
1325
1326 if ((poll_evtchn == port || poll_evtchn == -1) &&
1327 test_and_clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask)) {
1328 kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1329 kvm_vcpu_kick(vcpu);
1330 }
1331 }
1332
1333 /*
1334 * The return value from this function is propagated to kvm_set_irq() API,
1335 * so it returns:
1336 * < 0 Interrupt was ignored (masked or not delivered for other reasons)
1337 * = 0 Interrupt was coalesced (previous irq is still pending)
1338 * > 0 Number of CPUs interrupt was delivered to
1339 *
1340 * It is also called directly from kvm_arch_set_irq_inatomic(), where the
1341 * only check on its return value is a comparison with -EWOULDBLOCK'.
1342 */
kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn * xe,struct kvm * kvm)1343 int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm)
1344 {
1345 struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1346 struct kvm_vcpu *vcpu;
1347 unsigned long *pending_bits, *mask_bits;
1348 unsigned long flags;
1349 int port_word_bit;
1350 bool kick_vcpu = false;
1351 int vcpu_idx, idx, rc;
1352
1353 vcpu_idx = READ_ONCE(xe->vcpu_idx);
1354 if (vcpu_idx >= 0)
1355 vcpu = kvm_get_vcpu(kvm, vcpu_idx);
1356 else {
1357 vcpu = kvm_get_vcpu_by_id(kvm, xe->vcpu_id);
1358 if (!vcpu)
1359 return -EINVAL;
1360 WRITE_ONCE(xe->vcpu_idx, vcpu->vcpu_idx);
1361 }
1362
1363 if (!vcpu->arch.xen.vcpu_info_cache.active)
1364 return -EINVAL;
1365
1366 if (xe->port >= max_evtchn_port(kvm))
1367 return -EINVAL;
1368
1369 rc = -EWOULDBLOCK;
1370
1371 idx = srcu_read_lock(&kvm->srcu);
1372
1373 read_lock_irqsave(&gpc->lock, flags);
1374 if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, PAGE_SIZE))
1375 goto out_rcu;
1376
1377 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1378 struct shared_info *shinfo = gpc->khva;
1379 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1380 mask_bits = (unsigned long *)&shinfo->evtchn_mask;
1381 port_word_bit = xe->port / 64;
1382 } else {
1383 struct compat_shared_info *shinfo = gpc->khva;
1384 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1385 mask_bits = (unsigned long *)&shinfo->evtchn_mask;
1386 port_word_bit = xe->port / 32;
1387 }
1388
1389 /*
1390 * If this port wasn't already set, and if it isn't masked, then
1391 * we try to set the corresponding bit in the in-kernel shadow of
1392 * evtchn_pending_sel for the target vCPU. And if *that* wasn't
1393 * already set, then we kick the vCPU in question to write to the
1394 * *real* evtchn_pending_sel in its own guest vcpu_info struct.
1395 */
1396 if (test_and_set_bit(xe->port, pending_bits)) {
1397 rc = 0; /* It was already raised */
1398 } else if (test_bit(xe->port, mask_bits)) {
1399 rc = -ENOTCONN; /* Masked */
1400 kvm_xen_check_poller(vcpu, xe->port);
1401 } else {
1402 rc = 1; /* Delivered to the bitmap in shared_info. */
1403 /* Now switch to the vCPU's vcpu_info to set the index and pending_sel */
1404 read_unlock_irqrestore(&gpc->lock, flags);
1405 gpc = &vcpu->arch.xen.vcpu_info_cache;
1406
1407 read_lock_irqsave(&gpc->lock, flags);
1408 if (!kvm_gfn_to_pfn_cache_check(kvm, gpc, gpc->gpa, sizeof(struct vcpu_info))) {
1409 /*
1410 * Could not access the vcpu_info. Set the bit in-kernel
1411 * and prod the vCPU to deliver it for itself.
1412 */
1413 if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel))
1414 kick_vcpu = true;
1415 goto out_rcu;
1416 }
1417
1418 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1419 struct vcpu_info *vcpu_info = gpc->khva;
1420 if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) {
1421 WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
1422 kick_vcpu = true;
1423 }
1424 } else {
1425 struct compat_vcpu_info *vcpu_info = gpc->khva;
1426 if (!test_and_set_bit(port_word_bit,
1427 (unsigned long *)&vcpu_info->evtchn_pending_sel)) {
1428 WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
1429 kick_vcpu = true;
1430 }
1431 }
1432
1433 /* For the per-vCPU lapic vector, deliver it as MSI. */
1434 if (kick_vcpu && vcpu->arch.xen.upcall_vector) {
1435 kvm_xen_inject_vcpu_vector(vcpu);
1436 kick_vcpu = false;
1437 }
1438 }
1439
1440 out_rcu:
1441 read_unlock_irqrestore(&gpc->lock, flags);
1442 srcu_read_unlock(&kvm->srcu, idx);
1443
1444 if (kick_vcpu) {
1445 kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1446 kvm_vcpu_kick(vcpu);
1447 }
1448
1449 return rc;
1450 }
1451
kvm_xen_set_evtchn(struct kvm_xen_evtchn * xe,struct kvm * kvm)1452 static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm)
1453 {
1454 bool mm_borrowed = false;
1455 int rc;
1456
1457 rc = kvm_xen_set_evtchn_fast(xe, kvm);
1458 if (rc != -EWOULDBLOCK)
1459 return rc;
1460
1461 if (current->mm != kvm->mm) {
1462 /*
1463 * If not on a thread which already belongs to this KVM,
1464 * we'd better be in the irqfd workqueue.
1465 */
1466 if (WARN_ON_ONCE(current->mm))
1467 return -EINVAL;
1468
1469 kthread_use_mm(kvm->mm);
1470 mm_borrowed = true;
1471 }
1472
1473 /*
1474 * For the irqfd workqueue, using the main kvm->lock mutex is
1475 * fine since this function is invoked from kvm_set_irq() with
1476 * no other lock held, no srcu. In future if it will be called
1477 * directly from a vCPU thread (e.g. on hypercall for an IPI)
1478 * then it may need to switch to using a leaf-node mutex for
1479 * serializing the shared_info mapping.
1480 */
1481 mutex_lock(&kvm->lock);
1482
1483 /*
1484 * It is theoretically possible for the page to be unmapped
1485 * and the MMU notifier to invalidate the shared_info before
1486 * we even get to use it. In that case, this looks like an
1487 * infinite loop. It was tempting to do it via the userspace
1488 * HVA instead... but that just *hides* the fact that it's
1489 * an infinite loop, because if a fault occurs and it waits
1490 * for the page to come back, it can *still* immediately
1491 * fault and have to wait again, repeatedly.
1492 *
1493 * Conversely, the page could also have been reinstated by
1494 * another thread before we even obtain the mutex above, so
1495 * check again *first* before remapping it.
1496 */
1497 do {
1498 struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1499 int idx;
1500
1501 rc = kvm_xen_set_evtchn_fast(xe, kvm);
1502 if (rc != -EWOULDBLOCK)
1503 break;
1504
1505 idx = srcu_read_lock(&kvm->srcu);
1506 rc = kvm_gfn_to_pfn_cache_refresh(kvm, gpc, gpc->gpa, PAGE_SIZE);
1507 srcu_read_unlock(&kvm->srcu, idx);
1508 } while(!rc);
1509
1510 mutex_unlock(&kvm->lock);
1511
1512 if (mm_borrowed)
1513 kthread_unuse_mm(kvm->mm);
1514
1515 return rc;
1516 }
1517
1518 /* This is the version called from kvm_set_irq() as the .set function */
evtchn_set_fn(struct kvm_kernel_irq_routing_entry * e,struct kvm * kvm,int irq_source_id,int level,bool line_status)1519 static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
1520 int irq_source_id, int level, bool line_status)
1521 {
1522 if (!level)
1523 return -EINVAL;
1524
1525 return kvm_xen_set_evtchn(&e->xen_evtchn, kvm);
1526 }
1527
1528 /*
1529 * Set up an event channel interrupt from the KVM IRQ routing table.
1530 * Used for e.g. PIRQ from passed through physical devices.
1531 */
kvm_xen_setup_evtchn(struct kvm * kvm,struct kvm_kernel_irq_routing_entry * e,const struct kvm_irq_routing_entry * ue)1532 int kvm_xen_setup_evtchn(struct kvm *kvm,
1533 struct kvm_kernel_irq_routing_entry *e,
1534 const struct kvm_irq_routing_entry *ue)
1535
1536 {
1537 struct kvm_vcpu *vcpu;
1538
1539 if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm))
1540 return -EINVAL;
1541
1542 /* We only support 2 level event channels for now */
1543 if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1544 return -EINVAL;
1545
1546 /*
1547 * Xen gives us interesting mappings from vCPU index to APIC ID,
1548 * which means kvm_get_vcpu_by_id() has to iterate over all vCPUs
1549 * to find it. Do that once at setup time, instead of every time.
1550 * But beware that on live update / live migration, the routing
1551 * table might be reinstated before the vCPU threads have finished
1552 * recreating their vCPUs.
1553 */
1554 vcpu = kvm_get_vcpu_by_id(kvm, ue->u.xen_evtchn.vcpu);
1555 if (vcpu)
1556 e->xen_evtchn.vcpu_idx = vcpu->vcpu_idx;
1557 else
1558 e->xen_evtchn.vcpu_idx = -1;
1559
1560 e->xen_evtchn.port = ue->u.xen_evtchn.port;
1561 e->xen_evtchn.vcpu_id = ue->u.xen_evtchn.vcpu;
1562 e->xen_evtchn.priority = ue->u.xen_evtchn.priority;
1563 e->set = evtchn_set_fn;
1564
1565 return 0;
1566 }
1567
1568 /*
1569 * Explicit event sending from userspace with KVM_XEN_HVM_EVTCHN_SEND ioctl.
1570 */
kvm_xen_hvm_evtchn_send(struct kvm * kvm,struct kvm_irq_routing_xen_evtchn * uxe)1571 int kvm_xen_hvm_evtchn_send(struct kvm *kvm, struct kvm_irq_routing_xen_evtchn *uxe)
1572 {
1573 struct kvm_xen_evtchn e;
1574 int ret;
1575
1576 if (!uxe->port || uxe->port >= max_evtchn_port(kvm))
1577 return -EINVAL;
1578
1579 /* We only support 2 level event channels for now */
1580 if (uxe->priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1581 return -EINVAL;
1582
1583 e.port = uxe->port;
1584 e.vcpu_id = uxe->vcpu;
1585 e.vcpu_idx = -1;
1586 e.priority = uxe->priority;
1587
1588 ret = kvm_xen_set_evtchn(&e, kvm);
1589
1590 /*
1591 * None of that 'return 1 if it actually got delivered' nonsense.
1592 * We don't care if it was masked (-ENOTCONN) either.
1593 */
1594 if (ret > 0 || ret == -ENOTCONN)
1595 ret = 0;
1596
1597 return ret;
1598 }
1599
1600 /*
1601 * Support for *outbound* event channel events via the EVTCHNOP_send hypercall.
1602 */
1603 struct evtchnfd {
1604 u32 send_port;
1605 u32 type;
1606 union {
1607 struct kvm_xen_evtchn port;
1608 struct {
1609 u32 port; /* zero */
1610 struct eventfd_ctx *ctx;
1611 } eventfd;
1612 } deliver;
1613 };
1614
1615 /*
1616 * Update target vCPU or priority for a registered sending channel.
1617 */
kvm_xen_eventfd_update(struct kvm * kvm,struct kvm_xen_hvm_attr * data)1618 static int kvm_xen_eventfd_update(struct kvm *kvm,
1619 struct kvm_xen_hvm_attr *data)
1620 {
1621 u32 port = data->u.evtchn.send_port;
1622 struct evtchnfd *evtchnfd;
1623
1624 if (!port || port >= max_evtchn_port(kvm))
1625 return -EINVAL;
1626
1627 mutex_lock(&kvm->lock);
1628 evtchnfd = idr_find(&kvm->arch.xen.evtchn_ports, port);
1629 mutex_unlock(&kvm->lock);
1630
1631 if (!evtchnfd)
1632 return -ENOENT;
1633
1634 /* For an UPDATE, nothing may change except the priority/vcpu */
1635 if (evtchnfd->type != data->u.evtchn.type)
1636 return -EINVAL;
1637
1638 /*
1639 * Port cannot change, and if it's zero that was an eventfd
1640 * which can't be changed either.
1641 */
1642 if (!evtchnfd->deliver.port.port ||
1643 evtchnfd->deliver.port.port != data->u.evtchn.deliver.port.port)
1644 return -EINVAL;
1645
1646 /* We only support 2 level event channels for now */
1647 if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1648 return -EINVAL;
1649
1650 mutex_lock(&kvm->lock);
1651 evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
1652 if (evtchnfd->deliver.port.vcpu_id != data->u.evtchn.deliver.port.vcpu) {
1653 evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
1654 evtchnfd->deliver.port.vcpu_idx = -1;
1655 }
1656 mutex_unlock(&kvm->lock);
1657 return 0;
1658 }
1659
1660 /*
1661 * Configure the target (eventfd or local port delivery) for sending on
1662 * a given event channel.
1663 */
kvm_xen_eventfd_assign(struct kvm * kvm,struct kvm_xen_hvm_attr * data)1664 static int kvm_xen_eventfd_assign(struct kvm *kvm,
1665 struct kvm_xen_hvm_attr *data)
1666 {
1667 u32 port = data->u.evtchn.send_port;
1668 struct eventfd_ctx *eventfd = NULL;
1669 struct evtchnfd *evtchnfd = NULL;
1670 int ret = -EINVAL;
1671
1672 if (!port || port >= max_evtchn_port(kvm))
1673 return -EINVAL;
1674
1675 evtchnfd = kzalloc(sizeof(struct evtchnfd), GFP_KERNEL);
1676 if (!evtchnfd)
1677 return -ENOMEM;
1678
1679 switch(data->u.evtchn.type) {
1680 case EVTCHNSTAT_ipi:
1681 /* IPI must map back to the same port# */
1682 if (data->u.evtchn.deliver.port.port != data->u.evtchn.send_port)
1683 goto out_noeventfd; /* -EINVAL */
1684 break;
1685
1686 case EVTCHNSTAT_interdomain:
1687 if (data->u.evtchn.deliver.port.port) {
1688 if (data->u.evtchn.deliver.port.port >= max_evtchn_port(kvm))
1689 goto out_noeventfd; /* -EINVAL */
1690 } else {
1691 eventfd = eventfd_ctx_fdget(data->u.evtchn.deliver.eventfd.fd);
1692 if (IS_ERR(eventfd)) {
1693 ret = PTR_ERR(eventfd);
1694 goto out_noeventfd;
1695 }
1696 }
1697 break;
1698
1699 case EVTCHNSTAT_virq:
1700 case EVTCHNSTAT_closed:
1701 case EVTCHNSTAT_unbound:
1702 case EVTCHNSTAT_pirq:
1703 default: /* Unknown event channel type */
1704 goto out; /* -EINVAL */
1705 }
1706
1707 evtchnfd->send_port = data->u.evtchn.send_port;
1708 evtchnfd->type = data->u.evtchn.type;
1709 if (eventfd) {
1710 evtchnfd->deliver.eventfd.ctx = eventfd;
1711 } else {
1712 /* We only support 2 level event channels for now */
1713 if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1714 goto out; /* -EINVAL; */
1715
1716 evtchnfd->deliver.port.port = data->u.evtchn.deliver.port.port;
1717 evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
1718 evtchnfd->deliver.port.vcpu_idx = -1;
1719 evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
1720 }
1721
1722 mutex_lock(&kvm->lock);
1723 ret = idr_alloc(&kvm->arch.xen.evtchn_ports, evtchnfd, port, port + 1,
1724 GFP_KERNEL);
1725 mutex_unlock(&kvm->lock);
1726 if (ret >= 0)
1727 return 0;
1728
1729 if (ret == -ENOSPC)
1730 ret = -EEXIST;
1731 out:
1732 if (eventfd)
1733 eventfd_ctx_put(eventfd);
1734 out_noeventfd:
1735 kfree(evtchnfd);
1736 return ret;
1737 }
1738
kvm_xen_eventfd_deassign(struct kvm * kvm,u32 port)1739 static int kvm_xen_eventfd_deassign(struct kvm *kvm, u32 port)
1740 {
1741 struct evtchnfd *evtchnfd;
1742
1743 mutex_lock(&kvm->lock);
1744 evtchnfd = idr_remove(&kvm->arch.xen.evtchn_ports, port);
1745 mutex_unlock(&kvm->lock);
1746
1747 if (!evtchnfd)
1748 return -ENOENT;
1749
1750 if (kvm)
1751 synchronize_srcu(&kvm->srcu);
1752 if (!evtchnfd->deliver.port.port)
1753 eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
1754 kfree(evtchnfd);
1755 return 0;
1756 }
1757
kvm_xen_eventfd_reset(struct kvm * kvm)1758 static int kvm_xen_eventfd_reset(struct kvm *kvm)
1759 {
1760 struct evtchnfd *evtchnfd;
1761 int i;
1762
1763 mutex_lock(&kvm->lock);
1764 idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
1765 idr_remove(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port);
1766 synchronize_srcu(&kvm->srcu);
1767 if (!evtchnfd->deliver.port.port)
1768 eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
1769 kfree(evtchnfd);
1770 }
1771 mutex_unlock(&kvm->lock);
1772
1773 return 0;
1774 }
1775
kvm_xen_setattr_evtchn(struct kvm * kvm,struct kvm_xen_hvm_attr * data)1776 static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
1777 {
1778 u32 port = data->u.evtchn.send_port;
1779
1780 if (data->u.evtchn.flags == KVM_XEN_EVTCHN_RESET)
1781 return kvm_xen_eventfd_reset(kvm);
1782
1783 if (!port || port >= max_evtchn_port(kvm))
1784 return -EINVAL;
1785
1786 if (data->u.evtchn.flags == KVM_XEN_EVTCHN_DEASSIGN)
1787 return kvm_xen_eventfd_deassign(kvm, port);
1788 if (data->u.evtchn.flags == KVM_XEN_EVTCHN_UPDATE)
1789 return kvm_xen_eventfd_update(kvm, data);
1790 if (data->u.evtchn.flags)
1791 return -EINVAL;
1792
1793 return kvm_xen_eventfd_assign(kvm, data);
1794 }
1795
kvm_xen_hcall_evtchn_send(struct kvm_vcpu * vcpu,u64 param,u64 * r)1796 static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
1797 {
1798 struct evtchnfd *evtchnfd;
1799 struct evtchn_send send;
1800 gpa_t gpa;
1801 int idx;
1802
1803 idx = srcu_read_lock(&vcpu->kvm->srcu);
1804 gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
1805 srcu_read_unlock(&vcpu->kvm->srcu, idx);
1806
1807 if (!gpa || kvm_vcpu_read_guest(vcpu, gpa, &send, sizeof(send))) {
1808 *r = -EFAULT;
1809 return true;
1810 }
1811
1812 /* The evtchn_ports idr is protected by vcpu->kvm->srcu */
1813 evtchnfd = idr_find(&vcpu->kvm->arch.xen.evtchn_ports, send.port);
1814 if (!evtchnfd)
1815 return false;
1816
1817 if (evtchnfd->deliver.port.port) {
1818 int ret = kvm_xen_set_evtchn(&evtchnfd->deliver.port, vcpu->kvm);
1819 if (ret < 0 && ret != -ENOTCONN)
1820 return false;
1821 } else {
1822 eventfd_signal(evtchnfd->deliver.eventfd.ctx, 1);
1823 }
1824
1825 *r = 0;
1826 return true;
1827 }
1828
kvm_xen_init_vcpu(struct kvm_vcpu * vcpu)1829 void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu)
1830 {
1831 vcpu->arch.xen.vcpu_id = vcpu->vcpu_idx;
1832 vcpu->arch.xen.poll_evtchn = 0;
1833
1834 timer_setup(&vcpu->arch.xen.poll_timer, cancel_evtchn_poll, 0);
1835
1836 kvm_gpc_init(&vcpu->arch.xen.runstate_cache);
1837 kvm_gpc_init(&vcpu->arch.xen.vcpu_info_cache);
1838 kvm_gpc_init(&vcpu->arch.xen.vcpu_time_info_cache);
1839 }
1840
kvm_xen_destroy_vcpu(struct kvm_vcpu * vcpu)1841 void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
1842 {
1843 if (kvm_xen_timer_enabled(vcpu))
1844 kvm_xen_stop_timer(vcpu);
1845
1846 kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.runstate_cache);
1847 kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_info_cache);
1848 kvm_gpc_deactivate(vcpu->kvm, &vcpu->arch.xen.vcpu_time_info_cache);
1849
1850 del_timer_sync(&vcpu->arch.xen.poll_timer);
1851 }
1852
kvm_xen_init_vm(struct kvm * kvm)1853 void kvm_xen_init_vm(struct kvm *kvm)
1854 {
1855 idr_init(&kvm->arch.xen.evtchn_ports);
1856 kvm_gpc_init(&kvm->arch.xen.shinfo_cache);
1857 }
1858
kvm_xen_destroy_vm(struct kvm * kvm)1859 void kvm_xen_destroy_vm(struct kvm *kvm)
1860 {
1861 struct evtchnfd *evtchnfd;
1862 int i;
1863
1864 kvm_gpc_deactivate(kvm, &kvm->arch.xen.shinfo_cache);
1865
1866 idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
1867 if (!evtchnfd->deliver.port.port)
1868 eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
1869 kfree(evtchnfd);
1870 }
1871 idr_destroy(&kvm->arch.xen.evtchn_ports);
1872
1873 if (kvm->arch.xen_hvm_config.msr)
1874 static_branch_slow_dec_deferred(&kvm_xen_enabled);
1875 }
1876