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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include "x86.h"
11#include "xen.h"
12#include "hyperv.h"
13#include "irq.h"
14
15#include <linux/eventfd.h>
16#include <linux/kvm_host.h>
17#include <linux/sched/stat.h>
18
19#include <trace/events/kvm.h>
20#include <xen/interface/xen.h>
21#include <xen/interface/vcpu.h>
22#include <xen/interface/version.h>
23#include <xen/interface/event_channel.h>
24#include <xen/interface/sched.h>
25
26#include <asm/xen/cpuid.h>
27#include <asm/pvclock.h>
28
29#include "cpuid.h"
30#include "trace.h"
31
32static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm);
33static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
34static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r);
35
36DEFINE_STATIC_KEY_DEFERRED_FALSE(kvm_xen_enabled, HZ);
37
38static int kvm_xen_shared_info_init(struct kvm *kvm)
39{
40 struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
41 struct pvclock_wall_clock *wc;
42 u32 *wc_sec_hi;
43 u32 wc_version;
44 u64 wall_nsec;
45 int ret = 0;
46 int idx = srcu_read_lock(&kvm->srcu);
47
48 read_lock_irq(&gpc->lock);
49 while (!kvm_gpc_check(gpc, PAGE_SIZE)) {
50 read_unlock_irq(&gpc->lock);
51
52 ret = kvm_gpc_refresh(gpc, PAGE_SIZE);
53 if (ret)
54 goto out;
55
56 read_lock_irq(&gpc->lock);
57 }
58
59 /*
60 * This code mirrors kvm_write_wall_clock() except that it writes
61 * directly through the pfn cache and doesn't mark the page dirty.
62 */
63 wall_nsec = kvm_get_wall_clock_epoch(kvm);
64
65 /* Paranoia checks on the 32-bit struct layout */
66 BUILD_BUG_ON(offsetof(struct compat_shared_info, wc) != 0x900);
67 BUILD_BUG_ON(offsetof(struct compat_shared_info, arch.wc_sec_hi) != 0x924);
68 BUILD_BUG_ON(offsetof(struct pvclock_vcpu_time_info, version) != 0);
69
70#ifdef CONFIG_X86_64
71 /* Paranoia checks on the 64-bit struct layout */
72 BUILD_BUG_ON(offsetof(struct shared_info, wc) != 0xc00);
73 BUILD_BUG_ON(offsetof(struct shared_info, wc_sec_hi) != 0xc0c);
74
75 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
76 struct shared_info *shinfo = gpc->khva;
77
78 wc_sec_hi = &shinfo->wc_sec_hi;
79 wc = &shinfo->wc;
80 } else
81#endif
82 {
83 struct compat_shared_info *shinfo = gpc->khva;
84
85 wc_sec_hi = &shinfo->arch.wc_sec_hi;
86 wc = &shinfo->wc;
87 }
88
89 /* Increment and ensure an odd value */
90 wc_version = wc->version = (wc->version + 1) | 1;
91 smp_wmb();
92
93 wc->nsec = do_div(wall_nsec, NSEC_PER_SEC);
94 wc->sec = (u32)wall_nsec;
95 *wc_sec_hi = wall_nsec >> 32;
96 smp_wmb();
97
98 wc->version = wc_version + 1;
99 read_unlock_irq(&gpc->lock);
100
101 kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE);
102
103out:
104 srcu_read_unlock(&kvm->srcu, idx);
105 return ret;
106}
107
108void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu)
109{
110 if (atomic_read(&vcpu->arch.xen.timer_pending) > 0) {
111 struct kvm_xen_evtchn e;
112
113 e.vcpu_id = vcpu->vcpu_id;
114 e.vcpu_idx = vcpu->vcpu_idx;
115 e.port = vcpu->arch.xen.timer_virq;
116 e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
117
118 kvm_xen_set_evtchn(&e, vcpu->kvm);
119
120 vcpu->arch.xen.timer_expires = 0;
121 atomic_set(&vcpu->arch.xen.timer_pending, 0);
122 }
123}
124
125static enum hrtimer_restart xen_timer_callback(struct hrtimer *timer)
126{
127 struct kvm_vcpu *vcpu = container_of(timer, struct kvm_vcpu,
128 arch.xen.timer);
129 struct kvm_xen_evtchn e;
130 int rc;
131
132 if (atomic_read(&vcpu->arch.xen.timer_pending))
133 return HRTIMER_NORESTART;
134
135 e.vcpu_id = vcpu->vcpu_id;
136 e.vcpu_idx = vcpu->vcpu_idx;
137 e.port = vcpu->arch.xen.timer_virq;
138 e.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
139
140 rc = kvm_xen_set_evtchn_fast(&e, vcpu->kvm);
141 if (rc != -EWOULDBLOCK) {
142 vcpu->arch.xen.timer_expires = 0;
143 return HRTIMER_NORESTART;
144 }
145
146 atomic_inc(&vcpu->arch.xen.timer_pending);
147 kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
148 kvm_vcpu_kick(vcpu);
149
150 return HRTIMER_NORESTART;
151}
152
153static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 guest_abs,
154 bool linux_wa)
155{
156 int64_t kernel_now, delta;
157 uint64_t guest_now;
158
159 /*
160 * The guest provides the requested timeout in absolute nanoseconds
161 * of the KVM clock — as *it* sees it, based on the scaled TSC and
162 * the pvclock information provided by KVM.
163 *
164 * The kernel doesn't support hrtimers based on CLOCK_MONOTONIC_RAW
165 * so use CLOCK_MONOTONIC. In the timescales covered by timers, the
166 * difference won't matter much as there is no cumulative effect.
167 *
168 * Calculate the time for some arbitrary point in time around "now"
169 * in terms of both kvmclock and CLOCK_MONOTONIC. Calculate the
170 * delta between the kvmclock "now" value and the guest's requested
171 * timeout, apply the "Linux workaround" described below, and add
172 * the resulting delta to the CLOCK_MONOTONIC "now" value, to get
173 * the absolute CLOCK_MONOTONIC time at which the timer should
174 * fire.
175 */
176 if (vcpu->arch.hv_clock.version && vcpu->kvm->arch.use_master_clock &&
177 static_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
178 uint64_t host_tsc, guest_tsc;
179
180 if (!IS_ENABLED(CONFIG_64BIT) ||
181 !kvm_get_monotonic_and_clockread(&kernel_now, &host_tsc)) {
182 /*
183 * Don't fall back to get_kvmclock_ns() because it's
184 * broken; it has a systemic error in its results
185 * because it scales directly from host TSC to
186 * nanoseconds, and doesn't scale first to guest TSC
187 * and *then* to nanoseconds as the guest does.
188 *
189 * There is a small error introduced here because time
190 * continues to elapse between the ktime_get() and the
191 * subsequent rdtsc(). But not the systemic drift due
192 * to get_kvmclock_ns().
193 */
194 kernel_now = ktime_get(); /* This is CLOCK_MONOTONIC */
195 host_tsc = rdtsc();
196 }
197
198 /* Calculate the guest kvmclock as the guest would do it. */
199 guest_tsc = kvm_read_l1_tsc(vcpu, host_tsc);
200 guest_now = __pvclock_read_cycles(&vcpu->arch.hv_clock,
201 guest_tsc);
202 } else {
203 /*
204 * Without CONSTANT_TSC, get_kvmclock_ns() is the only option.
205 *
206 * Also if the guest PV clock hasn't been set up yet, as is
207 * likely to be the case during migration when the vCPU has
208 * not been run yet. It would be possible to calculate the
209 * scaling factors properly in that case but there's not much
210 * point in doing so. The get_kvmclock_ns() drift accumulates
211 * over time, so it's OK to use it at startup. Besides, on
212 * migration there's going to be a little bit of skew in the
213 * precise moment at which timers fire anyway. Often they'll
214 * be in the "past" by the time the VM is running again after
215 * migration.
216 */
217 guest_now = get_kvmclock_ns(vcpu->kvm);
218 kernel_now = ktime_get();
219 }
220
221 delta = guest_abs - guest_now;
222
223 /*
224 * Xen has a 'Linux workaround' in do_set_timer_op() which checks for
225 * negative absolute timeout values (caused by integer overflow), and
226 * for values about 13 days in the future (2^50ns) which would be
227 * caused by jiffies overflow. For those cases, Xen sets the timeout
228 * 100ms in the future (not *too* soon, since if a guest really did
229 * set a long timeout on purpose we don't want to keep churning CPU
230 * time by waking it up). Emulate Xen's workaround when starting the
231 * timer in response to __HYPERVISOR_set_timer_op.
232 */
233 if (linux_wa &&
234 unlikely((int64_t)guest_abs < 0 ||
235 (delta > 0 && (uint32_t) (delta >> 50) != 0))) {
236 delta = 100 * NSEC_PER_MSEC;
237 guest_abs = guest_now + delta;
238 }
239
240 /*
241 * Avoid races with the old timer firing. Checking timer_expires
242 * to avoid calling hrtimer_cancel() will only have false positives
243 * so is fine.
244 */
245 if (vcpu->arch.xen.timer_expires)
246 hrtimer_cancel(&vcpu->arch.xen.timer);
247
248 atomic_set(&vcpu->arch.xen.timer_pending, 0);
249 vcpu->arch.xen.timer_expires = guest_abs;
250
251 if (delta <= 0)
252 xen_timer_callback(&vcpu->arch.xen.timer);
253 else
254 hrtimer_start(&vcpu->arch.xen.timer,
255 ktime_add_ns(kernel_now, delta),
256 HRTIMER_MODE_ABS_HARD);
257}
258
259static void kvm_xen_stop_timer(struct kvm_vcpu *vcpu)
260{
261 hrtimer_cancel(&vcpu->arch.xen.timer);
262 vcpu->arch.xen.timer_expires = 0;
263 atomic_set(&vcpu->arch.xen.timer_pending, 0);
264}
265
266static void kvm_xen_update_runstate_guest(struct kvm_vcpu *v, bool atomic)
267{
268 struct kvm_vcpu_xen *vx = &v->arch.xen;
269 struct gfn_to_pfn_cache *gpc1 = &vx->runstate_cache;
270 struct gfn_to_pfn_cache *gpc2 = &vx->runstate2_cache;
271 size_t user_len, user_len1, user_len2;
272 struct vcpu_runstate_info rs;
273 unsigned long flags;
274 size_t times_ofs;
275 uint8_t *update_bit = NULL;
276 uint64_t entry_time;
277 uint64_t *rs_times;
278 int *rs_state;
279
280 /*
281 * The only difference between 32-bit and 64-bit versions of the
282 * runstate struct is the alignment of uint64_t in 32-bit, which
283 * means that the 64-bit version has an additional 4 bytes of
284 * padding after the first field 'state'. Let's be really really
285 * paranoid about that, and matching it with our internal data
286 * structures that we memcpy into it...
287 */
288 BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) != 0);
289 BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state) != 0);
290 BUILD_BUG_ON(sizeof(struct compat_vcpu_runstate_info) != 0x2c);
291#ifdef CONFIG_X86_64
292 /*
293 * The 64-bit structure has 4 bytes of padding before 'state_entry_time'
294 * so each subsequent field is shifted by 4, and it's 4 bytes longer.
295 */
296 BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
297 offsetof(struct compat_vcpu_runstate_info, state_entry_time) + 4);
298 BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, time) !=
299 offsetof(struct compat_vcpu_runstate_info, time) + 4);
300 BUILD_BUG_ON(sizeof(struct vcpu_runstate_info) != 0x2c + 4);
301#endif
302 /*
303 * The state field is in the same place at the start of both structs,
304 * and is the same size (int) as vx->current_runstate.
305 */
306 BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state) !=
307 offsetof(struct compat_vcpu_runstate_info, state));
308 BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state) !=
309 sizeof(vx->current_runstate));
310 BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state) !=
311 sizeof(vx->current_runstate));
312
313 /*
314 * The state_entry_time field is 64 bits in both versions, and the
315 * XEN_RUNSTATE_UPDATE flag is in the top bit, which given that x86
316 * is little-endian means that it's in the last *byte* of the word.
317 * That detail is important later.
318 */
319 BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, state_entry_time) !=
320 sizeof(uint64_t));
321 BUILD_BUG_ON(sizeof_field(struct compat_vcpu_runstate_info, state_entry_time) !=
322 sizeof(uint64_t));
323 BUILD_BUG_ON((XEN_RUNSTATE_UPDATE >> 56) != 0x80);
324
325 /*
326 * The time array is four 64-bit quantities in both versions, matching
327 * the vx->runstate_times and immediately following state_entry_time.
328 */
329 BUILD_BUG_ON(offsetof(struct vcpu_runstate_info, state_entry_time) !=
330 offsetof(struct vcpu_runstate_info, time) - sizeof(uint64_t));
331 BUILD_BUG_ON(offsetof(struct compat_vcpu_runstate_info, state_entry_time) !=
332 offsetof(struct compat_vcpu_runstate_info, time) - sizeof(uint64_t));
333 BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
334 sizeof_field(struct compat_vcpu_runstate_info, time));
335 BUILD_BUG_ON(sizeof_field(struct vcpu_runstate_info, time) !=
336 sizeof(vx->runstate_times));
337
338 if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) {
339 user_len = sizeof(struct vcpu_runstate_info);
340 times_ofs = offsetof(struct vcpu_runstate_info,
341 state_entry_time);
342 } else {
343 user_len = sizeof(struct compat_vcpu_runstate_info);
344 times_ofs = offsetof(struct compat_vcpu_runstate_info,
345 state_entry_time);
346 }
347
348 /*
349 * There are basically no alignment constraints. The guest can set it
350 * up so it crosses from one page to the next, and at arbitrary byte
351 * alignment (and the 32-bit ABI doesn't align the 64-bit integers
352 * anyway, even if the overall struct had been 64-bit aligned).
353 */
354 if ((gpc1->gpa & ~PAGE_MASK) + user_len >= PAGE_SIZE) {
355 user_len1 = PAGE_SIZE - (gpc1->gpa & ~PAGE_MASK);
356 user_len2 = user_len - user_len1;
357 } else {
358 user_len1 = user_len;
359 user_len2 = 0;
360 }
361 BUG_ON(user_len1 + user_len2 != user_len);
362
363 retry:
364 /*
365 * Attempt to obtain the GPC lock on *both* (if there are two)
366 * gfn_to_pfn caches that cover the region.
367 */
368 if (atomic) {
369 local_irq_save(flags);
370 if (!read_trylock(&gpc1->lock)) {
371 local_irq_restore(flags);
372 return;
373 }
374 } else {
375 read_lock_irqsave(&gpc1->lock, flags);
376 }
377 while (!kvm_gpc_check(gpc1, user_len1)) {
378 read_unlock_irqrestore(&gpc1->lock, flags);
379
380 /* When invoked from kvm_sched_out() we cannot sleep */
381 if (atomic)
382 return;
383
384 if (kvm_gpc_refresh(gpc1, user_len1))
385 return;
386
387 read_lock_irqsave(&gpc1->lock, flags);
388 }
389
390 if (likely(!user_len2)) {
391 /*
392 * Set up three pointers directly to the runstate_info
393 * struct in the guest (via the GPC).
394 *
395 * • @rs_state → state field
396 * • @rs_times → state_entry_time field.
397 * • @update_bit → last byte of state_entry_time, which
398 * contains the XEN_RUNSTATE_UPDATE bit.
399 */
400 rs_state = gpc1->khva;
401 rs_times = gpc1->khva + times_ofs;
402 if (v->kvm->arch.xen.runstate_update_flag)
403 update_bit = ((void *)(&rs_times[1])) - 1;
404 } else {
405 /*
406 * The guest's runstate_info is split across two pages and we
407 * need to hold and validate both GPCs simultaneously. We can
408 * declare a lock ordering GPC1 > GPC2 because nothing else
409 * takes them more than one at a time. Set a subclass on the
410 * gpc1 lock to make lockdep shut up about it.
411 */
412 lock_set_subclass(&gpc1->lock.dep_map, 1, _THIS_IP_);
413 if (atomic) {
414 if (!read_trylock(&gpc2->lock)) {
415 read_unlock_irqrestore(&gpc1->lock, flags);
416 return;
417 }
418 } else {
419 read_lock(&gpc2->lock);
420 }
421
422 if (!kvm_gpc_check(gpc2, user_len2)) {
423 read_unlock(&gpc2->lock);
424 read_unlock_irqrestore(&gpc1->lock, flags);
425
426 /* When invoked from kvm_sched_out() we cannot sleep */
427 if (atomic)
428 return;
429
430 /*
431 * Use kvm_gpc_activate() here because if the runstate
432 * area was configured in 32-bit mode and only extends
433 * to the second page now because the guest changed to
434 * 64-bit mode, the second GPC won't have been set up.
435 */
436 if (kvm_gpc_activate(gpc2, gpc1->gpa + user_len1,
437 user_len2))
438 return;
439
440 /*
441 * We dropped the lock on GPC1 so we have to go all the
442 * way back and revalidate that too.
443 */
444 goto retry;
445 }
446
447 /*
448 * In this case, the runstate_info struct will be assembled on
449 * the kernel stack (compat or not as appropriate) and will
450 * be copied to GPC1/GPC2 with a dual memcpy. Set up the three
451 * rs pointers accordingly.
452 */
453 rs_times = &rs.state_entry_time;
454
455 /*
456 * The rs_state pointer points to the start of what we'll
457 * copy to the guest, which in the case of a compat guest
458 * is the 32-bit field that the compiler thinks is padding.
459 */
460 rs_state = ((void *)rs_times) - times_ofs;
461
462 /*
463 * The update_bit is still directly in the guest memory,
464 * via one GPC or the other.
465 */
466 if (v->kvm->arch.xen.runstate_update_flag) {
467 if (user_len1 >= times_ofs + sizeof(uint64_t))
468 update_bit = gpc1->khva + times_ofs +
469 sizeof(uint64_t) - 1;
470 else
471 update_bit = gpc2->khva + times_ofs +
472 sizeof(uint64_t) - 1 - user_len1;
473 }
474
475#ifdef CONFIG_X86_64
476 /*
477 * Don't leak kernel memory through the padding in the 64-bit
478 * version of the struct.
479 */
480 memset(&rs, 0, offsetof(struct vcpu_runstate_info, state_entry_time));
481#endif
482 }
483
484 /*
485 * First, set the XEN_RUNSTATE_UPDATE bit in the top bit of the
486 * state_entry_time field, directly in the guest. We need to set
487 * that (and write-barrier) before writing to the rest of the
488 * structure, and clear it last. Just as Xen does, we address the
489 * single *byte* in which it resides because it might be in a
490 * different cache line to the rest of the 64-bit word, due to
491 * the (lack of) alignment constraints.
492 */
493 entry_time = vx->runstate_entry_time;
494 if (update_bit) {
495 entry_time |= XEN_RUNSTATE_UPDATE;
496 *update_bit = (vx->runstate_entry_time | XEN_RUNSTATE_UPDATE) >> 56;
497 smp_wmb();
498 }
499
500 /*
501 * Now assemble the actual structure, either on our kernel stack
502 * or directly in the guest according to how the rs_state and
503 * rs_times pointers were set up above.
504 */
505 *rs_state = vx->current_runstate;
506 rs_times[0] = entry_time;
507 memcpy(rs_times + 1, vx->runstate_times, sizeof(vx->runstate_times));
508
509 /* For the split case, we have to then copy it to the guest. */
510 if (user_len2) {
511 memcpy(gpc1->khva, rs_state, user_len1);
512 memcpy(gpc2->khva, ((void *)rs_state) + user_len1, user_len2);
513 }
514 smp_wmb();
515
516 /* Finally, clear the XEN_RUNSTATE_UPDATE bit. */
517 if (update_bit) {
518 entry_time &= ~XEN_RUNSTATE_UPDATE;
519 *update_bit = entry_time >> 56;
520 smp_wmb();
521 }
522
523 if (user_len2) {
524 kvm_gpc_mark_dirty_in_slot(gpc2);
525 read_unlock(&gpc2->lock);
526 }
527
528 kvm_gpc_mark_dirty_in_slot(gpc1);
529 read_unlock_irqrestore(&gpc1->lock, flags);
530}
531
532void kvm_xen_update_runstate(struct kvm_vcpu *v, int state)
533{
534 struct kvm_vcpu_xen *vx = &v->arch.xen;
535 u64 now = get_kvmclock_ns(v->kvm);
536 u64 delta_ns = now - vx->runstate_entry_time;
537 u64 run_delay = current->sched_info.run_delay;
538
539 if (unlikely(!vx->runstate_entry_time))
540 vx->current_runstate = RUNSTATE_offline;
541
542 /*
543 * Time waiting for the scheduler isn't "stolen" if the
544 * vCPU wasn't running anyway.
545 */
546 if (vx->current_runstate == RUNSTATE_running) {
547 u64 steal_ns = run_delay - vx->last_steal;
548
549 delta_ns -= steal_ns;
550
551 vx->runstate_times[RUNSTATE_runnable] += steal_ns;
552 }
553 vx->last_steal = run_delay;
554
555 vx->runstate_times[vx->current_runstate] += delta_ns;
556 vx->current_runstate = state;
557 vx->runstate_entry_time = now;
558
559 if (vx->runstate_cache.active)
560 kvm_xen_update_runstate_guest(v, state == RUNSTATE_runnable);
561}
562
563void kvm_xen_inject_vcpu_vector(struct kvm_vcpu *v)
564{
565 struct kvm_lapic_irq irq = { };
566
567 irq.dest_id = v->vcpu_id;
568 irq.vector = v->arch.xen.upcall_vector;
569 irq.dest_mode = APIC_DEST_PHYSICAL;
570 irq.shorthand = APIC_DEST_NOSHORT;
571 irq.delivery_mode = APIC_DM_FIXED;
572 irq.level = 1;
573
574 kvm_irq_delivery_to_apic(v->kvm, NULL, &irq, NULL);
575}
576
577/*
578 * On event channel delivery, the vcpu_info may not have been accessible.
579 * In that case, there are bits in vcpu->arch.xen.evtchn_pending_sel which
580 * need to be marked into the vcpu_info (and evtchn_upcall_pending set).
581 * Do so now that we can sleep in the context of the vCPU to bring the
582 * page in, and refresh the pfn cache for it.
583 */
584void kvm_xen_inject_pending_events(struct kvm_vcpu *v)
585{
586 unsigned long evtchn_pending_sel = READ_ONCE(v->arch.xen.evtchn_pending_sel);
587 struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
588 unsigned long flags;
589
590 if (!evtchn_pending_sel)
591 return;
592
593 /*
594 * Yes, this is an open-coded loop. But that's just what put_user()
595 * does anyway. Page it in and retry the instruction. We're just a
596 * little more honest about it.
597 */
598 read_lock_irqsave(&gpc->lock, flags);
599 while (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) {
600 read_unlock_irqrestore(&gpc->lock, flags);
601
602 if (kvm_gpc_refresh(gpc, sizeof(struct vcpu_info)))
603 return;
604
605 read_lock_irqsave(&gpc->lock, flags);
606 }
607
608 /* Now gpc->khva is a valid kernel address for the vcpu_info */
609 if (IS_ENABLED(CONFIG_64BIT) && v->kvm->arch.xen.long_mode) {
610 struct vcpu_info *vi = gpc->khva;
611
612 asm volatile(LOCK_PREFIX "orq %0, %1\n"
613 "notq %0\n"
614 LOCK_PREFIX "andq %0, %2\n"
615 : "=r" (evtchn_pending_sel),
616 "+m" (vi->evtchn_pending_sel),
617 "+m" (v->arch.xen.evtchn_pending_sel)
618 : "0" (evtchn_pending_sel));
619 WRITE_ONCE(vi->evtchn_upcall_pending, 1);
620 } else {
621 u32 evtchn_pending_sel32 = evtchn_pending_sel;
622 struct compat_vcpu_info *vi = gpc->khva;
623
624 asm volatile(LOCK_PREFIX "orl %0, %1\n"
625 "notl %0\n"
626 LOCK_PREFIX "andl %0, %2\n"
627 : "=r" (evtchn_pending_sel32),
628 "+m" (vi->evtchn_pending_sel),
629 "+m" (v->arch.xen.evtchn_pending_sel)
630 : "0" (evtchn_pending_sel32));
631 WRITE_ONCE(vi->evtchn_upcall_pending, 1);
632 }
633
634 kvm_gpc_mark_dirty_in_slot(gpc);
635 read_unlock_irqrestore(&gpc->lock, flags);
636
637 /* For the per-vCPU lapic vector, deliver it as MSI. */
638 if (v->arch.xen.upcall_vector)
639 kvm_xen_inject_vcpu_vector(v);
640}
641
642int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
643{
644 struct gfn_to_pfn_cache *gpc = &v->arch.xen.vcpu_info_cache;
645 unsigned long flags;
646 u8 rc = 0;
647
648 /*
649 * If the global upcall vector (HVMIRQ_callback_vector) is set and
650 * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending.
651 */
652
653 /* No need for compat handling here */
654 BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) !=
655 offsetof(struct compat_vcpu_info, evtchn_upcall_pending));
656 BUILD_BUG_ON(sizeof(rc) !=
657 sizeof_field(struct vcpu_info, evtchn_upcall_pending));
658 BUILD_BUG_ON(sizeof(rc) !=
659 sizeof_field(struct compat_vcpu_info, evtchn_upcall_pending));
660
661 read_lock_irqsave(&gpc->lock, flags);
662 while (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) {
663 read_unlock_irqrestore(&gpc->lock, flags);
664
665 /*
666 * This function gets called from kvm_vcpu_block() after setting the
667 * task to TASK_INTERRUPTIBLE, to see if it needs to wake immediately
668 * from a HLT. So we really mustn't sleep. If the page ended up absent
669 * at that point, just return 1 in order to trigger an immediate wake,
670 * and we'll end up getting called again from a context where we *can*
671 * fault in the page and wait for it.
672 */
673 if (in_atomic() || !task_is_running(current))
674 return 1;
675
676 if (kvm_gpc_refresh(gpc, sizeof(struct vcpu_info))) {
677 /*
678 * If this failed, userspace has screwed up the
679 * vcpu_info mapping. No interrupts for you.
680 */
681 return 0;
682 }
683 read_lock_irqsave(&gpc->lock, flags);
684 }
685
686 rc = ((struct vcpu_info *)gpc->khva)->evtchn_upcall_pending;
687 read_unlock_irqrestore(&gpc->lock, flags);
688 return rc;
689}
690
691int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
692{
693 int r = -ENOENT;
694
695
696 switch (data->type) {
697 case KVM_XEN_ATTR_TYPE_LONG_MODE:
698 if (!IS_ENABLED(CONFIG_64BIT) && data->u.long_mode) {
699 r = -EINVAL;
700 } else {
701 mutex_lock(&kvm->arch.xen.xen_lock);
702 kvm->arch.xen.long_mode = !!data->u.long_mode;
703
704 /*
705 * Re-initialize shared_info to put the wallclock in the
706 * correct place. Whilst it's not necessary to do this
707 * unless the mode is actually changed, it does no harm
708 * to make the call anyway.
709 */
710 r = kvm->arch.xen.shinfo_cache.active ?
711 kvm_xen_shared_info_init(kvm) : 0;
712 mutex_unlock(&kvm->arch.xen.xen_lock);
713 }
714 break;
715
716 case KVM_XEN_ATTR_TYPE_SHARED_INFO:
717 case KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA: {
718 int idx;
719
720 mutex_lock(&kvm->arch.xen.xen_lock);
721
722 idx = srcu_read_lock(&kvm->srcu);
723
724 if (data->type == KVM_XEN_ATTR_TYPE_SHARED_INFO) {
725 gfn_t gfn = data->u.shared_info.gfn;
726
727 if (gfn == KVM_XEN_INVALID_GFN) {
728 kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache);
729 r = 0;
730 } else {
731 r = kvm_gpc_activate(&kvm->arch.xen.shinfo_cache,
732 gfn_to_gpa(gfn), PAGE_SIZE);
733 }
734 } else {
735 void __user * hva = u64_to_user_ptr(data->u.shared_info.hva);
736
737 if (!PAGE_ALIGNED(hva)) {
738 r = -EINVAL;
739 } else if (!hva) {
740 kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache);
741 r = 0;
742 } else {
743 r = kvm_gpc_activate_hva(&kvm->arch.xen.shinfo_cache,
744 (unsigned long)hva, PAGE_SIZE);
745 }
746 }
747
748 srcu_read_unlock(&kvm->srcu, idx);
749
750 if (!r && kvm->arch.xen.shinfo_cache.active)
751 r = kvm_xen_shared_info_init(kvm);
752
753 mutex_unlock(&kvm->arch.xen.xen_lock);
754 break;
755 }
756 case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
757 if (data->u.vector && data->u.vector < 0x10)
758 r = -EINVAL;
759 else {
760 mutex_lock(&kvm->arch.xen.xen_lock);
761 kvm->arch.xen.upcall_vector = data->u.vector;
762 mutex_unlock(&kvm->arch.xen.xen_lock);
763 r = 0;
764 }
765 break;
766
767 case KVM_XEN_ATTR_TYPE_EVTCHN:
768 r = kvm_xen_setattr_evtchn(kvm, data);
769 break;
770
771 case KVM_XEN_ATTR_TYPE_XEN_VERSION:
772 mutex_lock(&kvm->arch.xen.xen_lock);
773 kvm->arch.xen.xen_version = data->u.xen_version;
774 mutex_unlock(&kvm->arch.xen.xen_lock);
775 r = 0;
776 break;
777
778 case KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG:
779 if (!sched_info_on()) {
780 r = -EOPNOTSUPP;
781 break;
782 }
783 mutex_lock(&kvm->arch.xen.xen_lock);
784 kvm->arch.xen.runstate_update_flag = !!data->u.runstate_update_flag;
785 mutex_unlock(&kvm->arch.xen.xen_lock);
786 r = 0;
787 break;
788
789 default:
790 break;
791 }
792
793 return r;
794}
795
796int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
797{
798 int r = -ENOENT;
799
800 mutex_lock(&kvm->arch.xen.xen_lock);
801
802 switch (data->type) {
803 case KVM_XEN_ATTR_TYPE_LONG_MODE:
804 data->u.long_mode = kvm->arch.xen.long_mode;
805 r = 0;
806 break;
807
808 case KVM_XEN_ATTR_TYPE_SHARED_INFO:
809 if (kvm_gpc_is_gpa_active(&kvm->arch.xen.shinfo_cache))
810 data->u.shared_info.gfn = gpa_to_gfn(kvm->arch.xen.shinfo_cache.gpa);
811 else
812 data->u.shared_info.gfn = KVM_XEN_INVALID_GFN;
813 r = 0;
814 break;
815
816 case KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA:
817 if (kvm_gpc_is_hva_active(&kvm->arch.xen.shinfo_cache))
818 data->u.shared_info.hva = kvm->arch.xen.shinfo_cache.uhva;
819 else
820 data->u.shared_info.hva = 0;
821 r = 0;
822 break;
823
824 case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
825 data->u.vector = kvm->arch.xen.upcall_vector;
826 r = 0;
827 break;
828
829 case KVM_XEN_ATTR_TYPE_XEN_VERSION:
830 data->u.xen_version = kvm->arch.xen.xen_version;
831 r = 0;
832 break;
833
834 case KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG:
835 if (!sched_info_on()) {
836 r = -EOPNOTSUPP;
837 break;
838 }
839 data->u.runstate_update_flag = kvm->arch.xen.runstate_update_flag;
840 r = 0;
841 break;
842
843 default:
844 break;
845 }
846
847 mutex_unlock(&kvm->arch.xen.xen_lock);
848 return r;
849}
850
851int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
852{
853 int idx, r = -ENOENT;
854
855 mutex_lock(&vcpu->kvm->arch.xen.xen_lock);
856 idx = srcu_read_lock(&vcpu->kvm->srcu);
857
858 switch (data->type) {
859 case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
860 case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA:
861 /* No compat necessary here. */
862 BUILD_BUG_ON(sizeof(struct vcpu_info) !=
863 sizeof(struct compat_vcpu_info));
864 BUILD_BUG_ON(offsetof(struct vcpu_info, time) !=
865 offsetof(struct compat_vcpu_info, time));
866
867 if (data->type == KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO) {
868 if (data->u.gpa == KVM_XEN_INVALID_GPA) {
869 kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
870 r = 0;
871 break;
872 }
873
874 r = kvm_gpc_activate(&vcpu->arch.xen.vcpu_info_cache,
875 data->u.gpa, sizeof(struct vcpu_info));
876 } else {
877 if (data->u.hva == 0) {
878 kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
879 r = 0;
880 break;
881 }
882
883 r = kvm_gpc_activate_hva(&vcpu->arch.xen.vcpu_info_cache,
884 data->u.hva, sizeof(struct vcpu_info));
885 }
886
887 if (!r)
888 kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
889
890 break;
891
892 case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
893 if (data->u.gpa == KVM_XEN_INVALID_GPA) {
894 kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_time_info_cache);
895 r = 0;
896 break;
897 }
898
899 r = kvm_gpc_activate(&vcpu->arch.xen.vcpu_time_info_cache,
900 data->u.gpa,
901 sizeof(struct pvclock_vcpu_time_info));
902 if (!r)
903 kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
904 break;
905
906 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR: {
907 size_t sz, sz1, sz2;
908
909 if (!sched_info_on()) {
910 r = -EOPNOTSUPP;
911 break;
912 }
913 if (data->u.gpa == KVM_XEN_INVALID_GPA) {
914 r = 0;
915 deactivate_out:
916 kvm_gpc_deactivate(&vcpu->arch.xen.runstate_cache);
917 kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
918 break;
919 }
920
921 /*
922 * If the guest switches to 64-bit mode after setting the runstate
923 * address, that's actually OK. kvm_xen_update_runstate_guest()
924 * will cope.
925 */
926 if (IS_ENABLED(CONFIG_64BIT) && vcpu->kvm->arch.xen.long_mode)
927 sz = sizeof(struct vcpu_runstate_info);
928 else
929 sz = sizeof(struct compat_vcpu_runstate_info);
930
931 /* How much fits in the (first) page? */
932 sz1 = PAGE_SIZE - (data->u.gpa & ~PAGE_MASK);
933 r = kvm_gpc_activate(&vcpu->arch.xen.runstate_cache,
934 data->u.gpa, sz1);
935 if (r)
936 goto deactivate_out;
937
938 /* Either map the second page, or deactivate the second GPC */
939 if (sz1 >= sz) {
940 kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
941 } else {
942 sz2 = sz - sz1;
943 BUG_ON((data->u.gpa + sz1) & ~PAGE_MASK);
944 r = kvm_gpc_activate(&vcpu->arch.xen.runstate2_cache,
945 data->u.gpa + sz1, sz2);
946 if (r)
947 goto deactivate_out;
948 }
949
950 kvm_xen_update_runstate_guest(vcpu, false);
951 break;
952 }
953 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
954 if (!sched_info_on()) {
955 r = -EOPNOTSUPP;
956 break;
957 }
958 if (data->u.runstate.state > RUNSTATE_offline) {
959 r = -EINVAL;
960 break;
961 }
962
963 kvm_xen_update_runstate(vcpu, data->u.runstate.state);
964 r = 0;
965 break;
966
967 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
968 if (!sched_info_on()) {
969 r = -EOPNOTSUPP;
970 break;
971 }
972 if (data->u.runstate.state > RUNSTATE_offline) {
973 r = -EINVAL;
974 break;
975 }
976 if (data->u.runstate.state_entry_time !=
977 (data->u.runstate.time_running +
978 data->u.runstate.time_runnable +
979 data->u.runstate.time_blocked +
980 data->u.runstate.time_offline)) {
981 r = -EINVAL;
982 break;
983 }
984 if (get_kvmclock_ns(vcpu->kvm) <
985 data->u.runstate.state_entry_time) {
986 r = -EINVAL;
987 break;
988 }
989
990 vcpu->arch.xen.current_runstate = data->u.runstate.state;
991 vcpu->arch.xen.runstate_entry_time =
992 data->u.runstate.state_entry_time;
993 vcpu->arch.xen.runstate_times[RUNSTATE_running] =
994 data->u.runstate.time_running;
995 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] =
996 data->u.runstate.time_runnable;
997 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] =
998 data->u.runstate.time_blocked;
999 vcpu->arch.xen.runstate_times[RUNSTATE_offline] =
1000 data->u.runstate.time_offline;
1001 vcpu->arch.xen.last_steal = current->sched_info.run_delay;
1002 r = 0;
1003 break;
1004
1005 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
1006 if (!sched_info_on()) {
1007 r = -EOPNOTSUPP;
1008 break;
1009 }
1010 if (data->u.runstate.state > RUNSTATE_offline &&
1011 data->u.runstate.state != (u64)-1) {
1012 r = -EINVAL;
1013 break;
1014 }
1015 /* The adjustment must add up */
1016 if (data->u.runstate.state_entry_time !=
1017 (data->u.runstate.time_running +
1018 data->u.runstate.time_runnable +
1019 data->u.runstate.time_blocked +
1020 data->u.runstate.time_offline)) {
1021 r = -EINVAL;
1022 break;
1023 }
1024
1025 if (get_kvmclock_ns(vcpu->kvm) <
1026 (vcpu->arch.xen.runstate_entry_time +
1027 data->u.runstate.state_entry_time)) {
1028 r = -EINVAL;
1029 break;
1030 }
1031
1032 vcpu->arch.xen.runstate_entry_time +=
1033 data->u.runstate.state_entry_time;
1034 vcpu->arch.xen.runstate_times[RUNSTATE_running] +=
1035 data->u.runstate.time_running;
1036 vcpu->arch.xen.runstate_times[RUNSTATE_runnable] +=
1037 data->u.runstate.time_runnable;
1038 vcpu->arch.xen.runstate_times[RUNSTATE_blocked] +=
1039 data->u.runstate.time_blocked;
1040 vcpu->arch.xen.runstate_times[RUNSTATE_offline] +=
1041 data->u.runstate.time_offline;
1042
1043 if (data->u.runstate.state <= RUNSTATE_offline)
1044 kvm_xen_update_runstate(vcpu, data->u.runstate.state);
1045 else if (vcpu->arch.xen.runstate_cache.active)
1046 kvm_xen_update_runstate_guest(vcpu, false);
1047 r = 0;
1048 break;
1049
1050 case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
1051 if (data->u.vcpu_id >= KVM_MAX_VCPUS)
1052 r = -EINVAL;
1053 else {
1054 vcpu->arch.xen.vcpu_id = data->u.vcpu_id;
1055 r = 0;
1056 }
1057 break;
1058
1059 case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
1060 if (data->u.timer.port &&
1061 data->u.timer.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL) {
1062 r = -EINVAL;
1063 break;
1064 }
1065
1066 /* Stop the timer (if it's running) before changing the vector */
1067 kvm_xen_stop_timer(vcpu);
1068 vcpu->arch.xen.timer_virq = data->u.timer.port;
1069
1070 /* Start the timer if the new value has a valid vector+expiry. */
1071 if (data->u.timer.port && data->u.timer.expires_ns)
1072 kvm_xen_start_timer(vcpu, data->u.timer.expires_ns, false);
1073
1074 r = 0;
1075 break;
1076
1077 case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
1078 if (data->u.vector && data->u.vector < 0x10)
1079 r = -EINVAL;
1080 else {
1081 vcpu->arch.xen.upcall_vector = data->u.vector;
1082 r = 0;
1083 }
1084 break;
1085
1086 default:
1087 break;
1088 }
1089
1090 srcu_read_unlock(&vcpu->kvm->srcu, idx);
1091 mutex_unlock(&vcpu->kvm->arch.xen.xen_lock);
1092 return r;
1093}
1094
1095int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
1096{
1097 int r = -ENOENT;
1098
1099 mutex_lock(&vcpu->kvm->arch.xen.xen_lock);
1100
1101 switch (data->type) {
1102 case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO:
1103 if (kvm_gpc_is_gpa_active(&vcpu->arch.xen.vcpu_info_cache))
1104 data->u.gpa = vcpu->arch.xen.vcpu_info_cache.gpa;
1105 else
1106 data->u.gpa = KVM_XEN_INVALID_GPA;
1107 r = 0;
1108 break;
1109
1110 case KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA:
1111 if (kvm_gpc_is_hva_active(&vcpu->arch.xen.vcpu_info_cache))
1112 data->u.hva = vcpu->arch.xen.vcpu_info_cache.uhva;
1113 else
1114 data->u.hva = 0;
1115 r = 0;
1116 break;
1117
1118 case KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO:
1119 if (vcpu->arch.xen.vcpu_time_info_cache.active)
1120 data->u.gpa = vcpu->arch.xen.vcpu_time_info_cache.gpa;
1121 else
1122 data->u.gpa = KVM_XEN_INVALID_GPA;
1123 r = 0;
1124 break;
1125
1126 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR:
1127 if (!sched_info_on()) {
1128 r = -EOPNOTSUPP;
1129 break;
1130 }
1131 if (vcpu->arch.xen.runstate_cache.active) {
1132 data->u.gpa = vcpu->arch.xen.runstate_cache.gpa;
1133 r = 0;
1134 }
1135 break;
1136
1137 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT:
1138 if (!sched_info_on()) {
1139 r = -EOPNOTSUPP;
1140 break;
1141 }
1142 data->u.runstate.state = vcpu->arch.xen.current_runstate;
1143 r = 0;
1144 break;
1145
1146 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA:
1147 if (!sched_info_on()) {
1148 r = -EOPNOTSUPP;
1149 break;
1150 }
1151 data->u.runstate.state = vcpu->arch.xen.current_runstate;
1152 data->u.runstate.state_entry_time =
1153 vcpu->arch.xen.runstate_entry_time;
1154 data->u.runstate.time_running =
1155 vcpu->arch.xen.runstate_times[RUNSTATE_running];
1156 data->u.runstate.time_runnable =
1157 vcpu->arch.xen.runstate_times[RUNSTATE_runnable];
1158 data->u.runstate.time_blocked =
1159 vcpu->arch.xen.runstate_times[RUNSTATE_blocked];
1160 data->u.runstate.time_offline =
1161 vcpu->arch.xen.runstate_times[RUNSTATE_offline];
1162 r = 0;
1163 break;
1164
1165 case KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST:
1166 r = -EINVAL;
1167 break;
1168
1169 case KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID:
1170 data->u.vcpu_id = vcpu->arch.xen.vcpu_id;
1171 r = 0;
1172 break;
1173
1174 case KVM_XEN_VCPU_ATTR_TYPE_TIMER:
1175 /*
1176 * Ensure a consistent snapshot of state is captured, with a
1177 * timer either being pending, or the event channel delivered
1178 * to the corresponding bit in the shared_info. Not still
1179 * lurking in the timer_pending flag for deferred delivery.
1180 * Purely as an optimisation, if the timer_expires field is
1181 * zero, that means the timer isn't active (or even in the
1182 * timer_pending flag) and there is no need to cancel it.
1183 */
1184 if (vcpu->arch.xen.timer_expires) {
1185 hrtimer_cancel(&vcpu->arch.xen.timer);
1186 kvm_xen_inject_timer_irqs(vcpu);
1187 }
1188
1189 data->u.timer.port = vcpu->arch.xen.timer_virq;
1190 data->u.timer.priority = KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL;
1191 data->u.timer.expires_ns = vcpu->arch.xen.timer_expires;
1192
1193 /*
1194 * The hrtimer may trigger and raise the IRQ immediately,
1195 * while the returned state causes it to be set up and
1196 * raised again on the destination system after migration.
1197 * That's fine, as the guest won't even have had a chance
1198 * to run and handle the interrupt. Asserting an already
1199 * pending event channel is idempotent.
1200 */
1201 if (vcpu->arch.xen.timer_expires)
1202 hrtimer_start_expires(&vcpu->arch.xen.timer,
1203 HRTIMER_MODE_ABS_HARD);
1204
1205 r = 0;
1206 break;
1207
1208 case KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR:
1209 data->u.vector = vcpu->arch.xen.upcall_vector;
1210 r = 0;
1211 break;
1212
1213 default:
1214 break;
1215 }
1216
1217 mutex_unlock(&vcpu->kvm->arch.xen.xen_lock);
1218 return r;
1219}
1220
1221int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data)
1222{
1223 struct kvm *kvm = vcpu->kvm;
1224 u32 page_num = data & ~PAGE_MASK;
1225 u64 page_addr = data & PAGE_MASK;
1226 bool lm = is_long_mode(vcpu);
1227 int r = 0;
1228
1229 mutex_lock(&kvm->arch.xen.xen_lock);
1230 if (kvm->arch.xen.long_mode != lm) {
1231 kvm->arch.xen.long_mode = lm;
1232
1233 /*
1234 * Re-initialize shared_info to put the wallclock in the
1235 * correct place.
1236 */
1237 if (kvm->arch.xen.shinfo_cache.active &&
1238 kvm_xen_shared_info_init(kvm))
1239 r = 1;
1240 }
1241 mutex_unlock(&kvm->arch.xen.xen_lock);
1242
1243 if (r)
1244 return r;
1245
1246 /*
1247 * If Xen hypercall intercept is enabled, fill the hypercall
1248 * page with VMCALL/VMMCALL instructions since that's what
1249 * we catch. Else the VMM has provided the hypercall pages
1250 * with instructions of its own choosing, so use those.
1251 */
1252 if (kvm_xen_hypercall_enabled(kvm)) {
1253 u8 instructions[32];
1254 int i;
1255
1256 if (page_num)
1257 return 1;
1258
1259 /* mov imm32, %eax */
1260 instructions[0] = 0xb8;
1261
1262 /* vmcall / vmmcall */
1263 kvm_x86_call(patch_hypercall)(vcpu, instructions + 5);
1264
1265 /* ret */
1266 instructions[8] = 0xc3;
1267
1268 /* int3 to pad */
1269 memset(instructions + 9, 0xcc, sizeof(instructions) - 9);
1270
1271 for (i = 0; i < PAGE_SIZE / sizeof(instructions); i++) {
1272 *(u32 *)&instructions[1] = i;
1273 if (kvm_vcpu_write_guest(vcpu,
1274 page_addr + (i * sizeof(instructions)),
1275 instructions, sizeof(instructions)))
1276 return 1;
1277 }
1278 } else {
1279 /*
1280 * Note, truncation is a non-issue as 'lm' is guaranteed to be
1281 * false for a 32-bit kernel, i.e. when hva_t is only 4 bytes.
1282 */
1283 hva_t blob_addr = lm ? kvm->arch.xen_hvm_config.blob_addr_64
1284 : kvm->arch.xen_hvm_config.blob_addr_32;
1285 u8 blob_size = lm ? kvm->arch.xen_hvm_config.blob_size_64
1286 : kvm->arch.xen_hvm_config.blob_size_32;
1287 u8 *page;
1288 int ret;
1289
1290 if (page_num >= blob_size)
1291 return 1;
1292
1293 blob_addr += page_num * PAGE_SIZE;
1294
1295 page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE);
1296 if (IS_ERR(page))
1297 return PTR_ERR(page);
1298
1299 ret = kvm_vcpu_write_guest(vcpu, page_addr, page, PAGE_SIZE);
1300 kfree(page);
1301 if (ret)
1302 return 1;
1303 }
1304 return 0;
1305}
1306
1307int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc)
1308{
1309 /* Only some feature flags need to be *enabled* by userspace */
1310 u32 permitted_flags = KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL |
1311 KVM_XEN_HVM_CONFIG_EVTCHN_SEND |
1312 KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE;
1313 u32 old_flags;
1314
1315 if (xhc->flags & ~permitted_flags)
1316 return -EINVAL;
1317
1318 /*
1319 * With hypercall interception the kernel generates its own
1320 * hypercall page so it must not be provided.
1321 */
1322 if ((xhc->flags & KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL) &&
1323 (xhc->blob_addr_32 || xhc->blob_addr_64 ||
1324 xhc->blob_size_32 || xhc->blob_size_64))
1325 return -EINVAL;
1326
1327 mutex_lock(&kvm->arch.xen.xen_lock);
1328
1329 if (xhc->msr && !kvm->arch.xen_hvm_config.msr)
1330 static_branch_inc(&kvm_xen_enabled.key);
1331 else if (!xhc->msr && kvm->arch.xen_hvm_config.msr)
1332 static_branch_slow_dec_deferred(&kvm_xen_enabled);
1333
1334 old_flags = kvm->arch.xen_hvm_config.flags;
1335 memcpy(&kvm->arch.xen_hvm_config, xhc, sizeof(*xhc));
1336
1337 mutex_unlock(&kvm->arch.xen.xen_lock);
1338
1339 if ((old_flags ^ xhc->flags) & KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE)
1340 kvm_make_all_cpus_request(kvm, KVM_REQ_CLOCK_UPDATE);
1341
1342 return 0;
1343}
1344
1345static int kvm_xen_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)
1346{
1347 kvm_rax_write(vcpu, result);
1348 return kvm_skip_emulated_instruction(vcpu);
1349}
1350
1351static int kvm_xen_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
1352{
1353 struct kvm_run *run = vcpu->run;
1354
1355 if (unlikely(!kvm_is_linear_rip(vcpu, vcpu->arch.xen.hypercall_rip)))
1356 return 1;
1357
1358 return kvm_xen_hypercall_set_result(vcpu, run->xen.u.hcall.result);
1359}
1360
1361static inline int max_evtchn_port(struct kvm *kvm)
1362{
1363 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode)
1364 return EVTCHN_2L_NR_CHANNELS;
1365 else
1366 return COMPAT_EVTCHN_2L_NR_CHANNELS;
1367}
1368
1369static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports,
1370 evtchn_port_t *ports)
1371{
1372 struct kvm *kvm = vcpu->kvm;
1373 struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1374 unsigned long *pending_bits;
1375 unsigned long flags;
1376 bool ret = true;
1377 int idx, i;
1378
1379 idx = srcu_read_lock(&kvm->srcu);
1380 read_lock_irqsave(&gpc->lock, flags);
1381 if (!kvm_gpc_check(gpc, PAGE_SIZE))
1382 goto out_rcu;
1383
1384 ret = false;
1385 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1386 struct shared_info *shinfo = gpc->khva;
1387 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1388 } else {
1389 struct compat_shared_info *shinfo = gpc->khva;
1390 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1391 }
1392
1393 for (i = 0; i < nr_ports; i++) {
1394 if (test_bit(ports[i], pending_bits)) {
1395 ret = true;
1396 break;
1397 }
1398 }
1399
1400 out_rcu:
1401 read_unlock_irqrestore(&gpc->lock, flags);
1402 srcu_read_unlock(&kvm->srcu, idx);
1403
1404 return ret;
1405}
1406
1407static bool kvm_xen_schedop_poll(struct kvm_vcpu *vcpu, bool longmode,
1408 u64 param, u64 *r)
1409{
1410 struct sched_poll sched_poll;
1411 evtchn_port_t port, *ports;
1412 struct x86_exception e;
1413 int i;
1414
1415 if (!lapic_in_kernel(vcpu) ||
1416 !(vcpu->kvm->arch.xen_hvm_config.flags & KVM_XEN_HVM_CONFIG_EVTCHN_SEND))
1417 return false;
1418
1419 if (IS_ENABLED(CONFIG_64BIT) && !longmode) {
1420 struct compat_sched_poll sp32;
1421
1422 /* Sanity check that the compat struct definition is correct */
1423 BUILD_BUG_ON(sizeof(sp32) != 16);
1424
1425 if (kvm_read_guest_virt(vcpu, param, &sp32, sizeof(sp32), &e)) {
1426 *r = -EFAULT;
1427 return true;
1428 }
1429
1430 /*
1431 * This is a 32-bit pointer to an array of evtchn_port_t which
1432 * are uint32_t, so once it's converted no further compat
1433 * handling is needed.
1434 */
1435 sched_poll.ports = (void *)(unsigned long)(sp32.ports);
1436 sched_poll.nr_ports = sp32.nr_ports;
1437 sched_poll.timeout = sp32.timeout;
1438 } else {
1439 if (kvm_read_guest_virt(vcpu, param, &sched_poll,
1440 sizeof(sched_poll), &e)) {
1441 *r = -EFAULT;
1442 return true;
1443 }
1444 }
1445
1446 if (unlikely(sched_poll.nr_ports > 1)) {
1447 /* Xen (unofficially) limits number of pollers to 128 */
1448 if (sched_poll.nr_ports > 128) {
1449 *r = -EINVAL;
1450 return true;
1451 }
1452
1453 ports = kmalloc_array(sched_poll.nr_ports,
1454 sizeof(*ports), GFP_KERNEL);
1455 if (!ports) {
1456 *r = -ENOMEM;
1457 return true;
1458 }
1459 } else
1460 ports = &port;
1461
1462 if (kvm_read_guest_virt(vcpu, (gva_t)sched_poll.ports, ports,
1463 sched_poll.nr_ports * sizeof(*ports), &e)) {
1464 *r = -EFAULT;
1465 return true;
1466 }
1467
1468 for (i = 0; i < sched_poll.nr_ports; i++) {
1469 if (ports[i] >= max_evtchn_port(vcpu->kvm)) {
1470 *r = -EINVAL;
1471 goto out;
1472 }
1473 }
1474
1475 if (sched_poll.nr_ports == 1)
1476 vcpu->arch.xen.poll_evtchn = port;
1477 else
1478 vcpu->arch.xen.poll_evtchn = -1;
1479
1480 set_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask);
1481
1482 if (!wait_pending_event(vcpu, sched_poll.nr_ports, ports)) {
1483 vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
1484
1485 if (sched_poll.timeout)
1486 mod_timer(&vcpu->arch.xen.poll_timer,
1487 jiffies + nsecs_to_jiffies(sched_poll.timeout));
1488
1489 kvm_vcpu_halt(vcpu);
1490
1491 if (sched_poll.timeout)
1492 del_timer(&vcpu->arch.xen.poll_timer);
1493
1494 vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
1495 }
1496
1497 vcpu->arch.xen.poll_evtchn = 0;
1498 *r = 0;
1499out:
1500 /* Really, this is only needed in case of timeout */
1501 clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask);
1502
1503 if (unlikely(sched_poll.nr_ports > 1))
1504 kfree(ports);
1505 return true;
1506}
1507
1508static void cancel_evtchn_poll(struct timer_list *t)
1509{
1510 struct kvm_vcpu *vcpu = from_timer(vcpu, t, arch.xen.poll_timer);
1511
1512 kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1513 kvm_vcpu_kick(vcpu);
1514}
1515
1516static bool kvm_xen_hcall_sched_op(struct kvm_vcpu *vcpu, bool longmode,
1517 int cmd, u64 param, u64 *r)
1518{
1519 switch (cmd) {
1520 case SCHEDOP_poll:
1521 if (kvm_xen_schedop_poll(vcpu, longmode, param, r))
1522 return true;
1523 fallthrough;
1524 case SCHEDOP_yield:
1525 kvm_vcpu_on_spin(vcpu, true);
1526 *r = 0;
1527 return true;
1528 default:
1529 break;
1530 }
1531
1532 return false;
1533}
1534
1535struct compat_vcpu_set_singleshot_timer {
1536 uint64_t timeout_abs_ns;
1537 uint32_t flags;
1538} __attribute__((packed));
1539
1540static bool kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, bool longmode, int cmd,
1541 int vcpu_id, u64 param, u64 *r)
1542{
1543 struct vcpu_set_singleshot_timer oneshot;
1544 struct x86_exception e;
1545
1546 if (!kvm_xen_timer_enabled(vcpu))
1547 return false;
1548
1549 switch (cmd) {
1550 case VCPUOP_set_singleshot_timer:
1551 if (vcpu->arch.xen.vcpu_id != vcpu_id) {
1552 *r = -EINVAL;
1553 return true;
1554 }
1555
1556 /*
1557 * The only difference for 32-bit compat is the 4 bytes of
1558 * padding after the interesting part of the structure. So
1559 * for a faithful emulation of Xen we have to *try* to copy
1560 * the padding and return -EFAULT if we can't. Otherwise we
1561 * might as well just have copied the 12-byte 32-bit struct.
1562 */
1563 BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
1564 offsetof(struct vcpu_set_singleshot_timer, timeout_abs_ns));
1565 BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, timeout_abs_ns) !=
1566 sizeof_field(struct vcpu_set_singleshot_timer, timeout_abs_ns));
1567 BUILD_BUG_ON(offsetof(struct compat_vcpu_set_singleshot_timer, flags) !=
1568 offsetof(struct vcpu_set_singleshot_timer, flags));
1569 BUILD_BUG_ON(sizeof_field(struct compat_vcpu_set_singleshot_timer, flags) !=
1570 sizeof_field(struct vcpu_set_singleshot_timer, flags));
1571
1572 if (kvm_read_guest_virt(vcpu, param, &oneshot, longmode ? sizeof(oneshot) :
1573 sizeof(struct compat_vcpu_set_singleshot_timer), &e)) {
1574 *r = -EFAULT;
1575 return true;
1576 }
1577
1578 kvm_xen_start_timer(vcpu, oneshot.timeout_abs_ns, false);
1579 *r = 0;
1580 return true;
1581
1582 case VCPUOP_stop_singleshot_timer:
1583 if (vcpu->arch.xen.vcpu_id != vcpu_id) {
1584 *r = -EINVAL;
1585 return true;
1586 }
1587 kvm_xen_stop_timer(vcpu);
1588 *r = 0;
1589 return true;
1590 }
1591
1592 return false;
1593}
1594
1595static bool kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout,
1596 u64 *r)
1597{
1598 if (!kvm_xen_timer_enabled(vcpu))
1599 return false;
1600
1601 if (timeout)
1602 kvm_xen_start_timer(vcpu, timeout, true);
1603 else
1604 kvm_xen_stop_timer(vcpu);
1605
1606 *r = 0;
1607 return true;
1608}
1609
1610int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
1611{
1612 bool longmode;
1613 u64 input, params[6], r = -ENOSYS;
1614 bool handled = false;
1615 u8 cpl;
1616
1617 input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);
1618
1619 /* Hyper-V hypercalls get bit 31 set in EAX */
1620 if ((input & 0x80000000) &&
1621 kvm_hv_hypercall_enabled(vcpu))
1622 return kvm_hv_hypercall(vcpu);
1623
1624 longmode = is_64_bit_hypercall(vcpu);
1625 if (!longmode) {
1626 params[0] = (u32)kvm_rbx_read(vcpu);
1627 params[1] = (u32)kvm_rcx_read(vcpu);
1628 params[2] = (u32)kvm_rdx_read(vcpu);
1629 params[3] = (u32)kvm_rsi_read(vcpu);
1630 params[4] = (u32)kvm_rdi_read(vcpu);
1631 params[5] = (u32)kvm_rbp_read(vcpu);
1632 }
1633#ifdef CONFIG_X86_64
1634 else {
1635 params[0] = (u64)kvm_rdi_read(vcpu);
1636 params[1] = (u64)kvm_rsi_read(vcpu);
1637 params[2] = (u64)kvm_rdx_read(vcpu);
1638 params[3] = (u64)kvm_r10_read(vcpu);
1639 params[4] = (u64)kvm_r8_read(vcpu);
1640 params[5] = (u64)kvm_r9_read(vcpu);
1641 }
1642#endif
1643 cpl = kvm_x86_call(get_cpl)(vcpu);
1644 trace_kvm_xen_hypercall(cpl, input, params[0], params[1], params[2],
1645 params[3], params[4], params[5]);
1646
1647 /*
1648 * Only allow hypercall acceleration for CPL0. The rare hypercalls that
1649 * are permitted in guest userspace can be handled by the VMM.
1650 */
1651 if (unlikely(cpl > 0))
1652 goto handle_in_userspace;
1653
1654 switch (input) {
1655 case __HYPERVISOR_xen_version:
1656 if (params[0] == XENVER_version && vcpu->kvm->arch.xen.xen_version) {
1657 r = vcpu->kvm->arch.xen.xen_version;
1658 handled = true;
1659 }
1660 break;
1661 case __HYPERVISOR_event_channel_op:
1662 if (params[0] == EVTCHNOP_send)
1663 handled = kvm_xen_hcall_evtchn_send(vcpu, params[1], &r);
1664 break;
1665 case __HYPERVISOR_sched_op:
1666 handled = kvm_xen_hcall_sched_op(vcpu, longmode, params[0],
1667 params[1], &r);
1668 break;
1669 case __HYPERVISOR_vcpu_op:
1670 handled = kvm_xen_hcall_vcpu_op(vcpu, longmode, params[0], params[1],
1671 params[2], &r);
1672 break;
1673 case __HYPERVISOR_set_timer_op: {
1674 u64 timeout = params[0];
1675 /* In 32-bit mode, the 64-bit timeout is in two 32-bit params. */
1676 if (!longmode)
1677 timeout |= params[1] << 32;
1678 handled = kvm_xen_hcall_set_timer_op(vcpu, timeout, &r);
1679 break;
1680 }
1681 default:
1682 break;
1683 }
1684
1685 if (handled)
1686 return kvm_xen_hypercall_set_result(vcpu, r);
1687
1688handle_in_userspace:
1689 vcpu->run->exit_reason = KVM_EXIT_XEN;
1690 vcpu->run->xen.type = KVM_EXIT_XEN_HCALL;
1691 vcpu->run->xen.u.hcall.longmode = longmode;
1692 vcpu->run->xen.u.hcall.cpl = cpl;
1693 vcpu->run->xen.u.hcall.input = input;
1694 vcpu->run->xen.u.hcall.params[0] = params[0];
1695 vcpu->run->xen.u.hcall.params[1] = params[1];
1696 vcpu->run->xen.u.hcall.params[2] = params[2];
1697 vcpu->run->xen.u.hcall.params[3] = params[3];
1698 vcpu->run->xen.u.hcall.params[4] = params[4];
1699 vcpu->run->xen.u.hcall.params[5] = params[5];
1700 vcpu->arch.xen.hypercall_rip = kvm_get_linear_rip(vcpu);
1701 vcpu->arch.complete_userspace_io =
1702 kvm_xen_hypercall_complete_userspace;
1703
1704 return 0;
1705}
1706
1707static void kvm_xen_check_poller(struct kvm_vcpu *vcpu, int port)
1708{
1709 int poll_evtchn = vcpu->arch.xen.poll_evtchn;
1710
1711 if ((poll_evtchn == port || poll_evtchn == -1) &&
1712 test_and_clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.xen.poll_mask)) {
1713 kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1714 kvm_vcpu_kick(vcpu);
1715 }
1716}
1717
1718/*
1719 * The return value from this function is propagated to kvm_set_irq() API,
1720 * so it returns:
1721 * < 0 Interrupt was ignored (masked or not delivered for other reasons)
1722 * = 0 Interrupt was coalesced (previous irq is still pending)
1723 * > 0 Number of CPUs interrupt was delivered to
1724 *
1725 * It is also called directly from kvm_arch_set_irq_inatomic(), where the
1726 * only check on its return value is a comparison with -EWOULDBLOCK'.
1727 */
1728int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe, struct kvm *kvm)
1729{
1730 struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1731 struct kvm_vcpu *vcpu;
1732 unsigned long *pending_bits, *mask_bits;
1733 unsigned long flags;
1734 int port_word_bit;
1735 bool kick_vcpu = false;
1736 int vcpu_idx, idx, rc;
1737
1738 vcpu_idx = READ_ONCE(xe->vcpu_idx);
1739 if (vcpu_idx >= 0)
1740 vcpu = kvm_get_vcpu(kvm, vcpu_idx);
1741 else {
1742 vcpu = kvm_get_vcpu_by_id(kvm, xe->vcpu_id);
1743 if (!vcpu)
1744 return -EINVAL;
1745 WRITE_ONCE(xe->vcpu_idx, vcpu->vcpu_idx);
1746 }
1747
1748 if (xe->port >= max_evtchn_port(kvm))
1749 return -EINVAL;
1750
1751 rc = -EWOULDBLOCK;
1752
1753 idx = srcu_read_lock(&kvm->srcu);
1754
1755 read_lock_irqsave(&gpc->lock, flags);
1756 if (!kvm_gpc_check(gpc, PAGE_SIZE))
1757 goto out_rcu;
1758
1759 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1760 struct shared_info *shinfo = gpc->khva;
1761 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1762 mask_bits = (unsigned long *)&shinfo->evtchn_mask;
1763 port_word_bit = xe->port / 64;
1764 } else {
1765 struct compat_shared_info *shinfo = gpc->khva;
1766 pending_bits = (unsigned long *)&shinfo->evtchn_pending;
1767 mask_bits = (unsigned long *)&shinfo->evtchn_mask;
1768 port_word_bit = xe->port / 32;
1769 }
1770
1771 /*
1772 * If this port wasn't already set, and if it isn't masked, then
1773 * we try to set the corresponding bit in the in-kernel shadow of
1774 * evtchn_pending_sel for the target vCPU. And if *that* wasn't
1775 * already set, then we kick the vCPU in question to write to the
1776 * *real* evtchn_pending_sel in its own guest vcpu_info struct.
1777 */
1778 if (test_and_set_bit(xe->port, pending_bits)) {
1779 rc = 0; /* It was already raised */
1780 } else if (test_bit(xe->port, mask_bits)) {
1781 rc = -ENOTCONN; /* Masked */
1782 kvm_xen_check_poller(vcpu, xe->port);
1783 } else {
1784 rc = 1; /* Delivered to the bitmap in shared_info. */
1785 /* Now switch to the vCPU's vcpu_info to set the index and pending_sel */
1786 read_unlock_irqrestore(&gpc->lock, flags);
1787 gpc = &vcpu->arch.xen.vcpu_info_cache;
1788
1789 read_lock_irqsave(&gpc->lock, flags);
1790 if (!kvm_gpc_check(gpc, sizeof(struct vcpu_info))) {
1791 /*
1792 * Could not access the vcpu_info. Set the bit in-kernel
1793 * and prod the vCPU to deliver it for itself.
1794 */
1795 if (!test_and_set_bit(port_word_bit, &vcpu->arch.xen.evtchn_pending_sel))
1796 kick_vcpu = true;
1797 goto out_rcu;
1798 }
1799
1800 if (IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode) {
1801 struct vcpu_info *vcpu_info = gpc->khva;
1802 if (!test_and_set_bit(port_word_bit, &vcpu_info->evtchn_pending_sel)) {
1803 WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
1804 kick_vcpu = true;
1805 }
1806 } else {
1807 struct compat_vcpu_info *vcpu_info = gpc->khva;
1808 if (!test_and_set_bit(port_word_bit,
1809 (unsigned long *)&vcpu_info->evtchn_pending_sel)) {
1810 WRITE_ONCE(vcpu_info->evtchn_upcall_pending, 1);
1811 kick_vcpu = true;
1812 }
1813 }
1814
1815 /* For the per-vCPU lapic vector, deliver it as MSI. */
1816 if (kick_vcpu && vcpu->arch.xen.upcall_vector) {
1817 kvm_xen_inject_vcpu_vector(vcpu);
1818 kick_vcpu = false;
1819 }
1820 }
1821
1822 out_rcu:
1823 read_unlock_irqrestore(&gpc->lock, flags);
1824 srcu_read_unlock(&kvm->srcu, idx);
1825
1826 if (kick_vcpu) {
1827 kvm_make_request(KVM_REQ_UNBLOCK, vcpu);
1828 kvm_vcpu_kick(vcpu);
1829 }
1830
1831 return rc;
1832}
1833
1834static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm)
1835{
1836 bool mm_borrowed = false;
1837 int rc;
1838
1839 rc = kvm_xen_set_evtchn_fast(xe, kvm);
1840 if (rc != -EWOULDBLOCK)
1841 return rc;
1842
1843 if (current->mm != kvm->mm) {
1844 /*
1845 * If not on a thread which already belongs to this KVM,
1846 * we'd better be in the irqfd workqueue.
1847 */
1848 if (WARN_ON_ONCE(current->mm))
1849 return -EINVAL;
1850
1851 kthread_use_mm(kvm->mm);
1852 mm_borrowed = true;
1853 }
1854
1855 /*
1856 * It is theoretically possible for the page to be unmapped
1857 * and the MMU notifier to invalidate the shared_info before
1858 * we even get to use it. In that case, this looks like an
1859 * infinite loop. It was tempting to do it via the userspace
1860 * HVA instead... but that just *hides* the fact that it's
1861 * an infinite loop, because if a fault occurs and it waits
1862 * for the page to come back, it can *still* immediately
1863 * fault and have to wait again, repeatedly.
1864 *
1865 * Conversely, the page could also have been reinstated by
1866 * another thread before we even obtain the mutex above, so
1867 * check again *first* before remapping it.
1868 */
1869 do {
1870 struct gfn_to_pfn_cache *gpc = &kvm->arch.xen.shinfo_cache;
1871 int idx;
1872
1873 rc = kvm_xen_set_evtchn_fast(xe, kvm);
1874 if (rc != -EWOULDBLOCK)
1875 break;
1876
1877 idx = srcu_read_lock(&kvm->srcu);
1878 rc = kvm_gpc_refresh(gpc, PAGE_SIZE);
1879 srcu_read_unlock(&kvm->srcu, idx);
1880 } while(!rc);
1881
1882 if (mm_borrowed)
1883 kthread_unuse_mm(kvm->mm);
1884
1885 return rc;
1886}
1887
1888/* This is the version called from kvm_set_irq() as the .set function */
1889static int evtchn_set_fn(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
1890 int irq_source_id, int level, bool line_status)
1891{
1892 if (!level)
1893 return -EINVAL;
1894
1895 return kvm_xen_set_evtchn(&e->xen_evtchn, kvm);
1896}
1897
1898/*
1899 * Set up an event channel interrupt from the KVM IRQ routing table.
1900 * Used for e.g. PIRQ from passed through physical devices.
1901 */
1902int kvm_xen_setup_evtchn(struct kvm *kvm,
1903 struct kvm_kernel_irq_routing_entry *e,
1904 const struct kvm_irq_routing_entry *ue)
1905
1906{
1907 struct kvm_vcpu *vcpu;
1908
1909 if (ue->u.xen_evtchn.port >= max_evtchn_port(kvm))
1910 return -EINVAL;
1911
1912 /* We only support 2 level event channels for now */
1913 if (ue->u.xen_evtchn.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1914 return -EINVAL;
1915
1916 /*
1917 * Xen gives us interesting mappings from vCPU index to APIC ID,
1918 * which means kvm_get_vcpu_by_id() has to iterate over all vCPUs
1919 * to find it. Do that once at setup time, instead of every time.
1920 * But beware that on live update / live migration, the routing
1921 * table might be reinstated before the vCPU threads have finished
1922 * recreating their vCPUs.
1923 */
1924 vcpu = kvm_get_vcpu_by_id(kvm, ue->u.xen_evtchn.vcpu);
1925 if (vcpu)
1926 e->xen_evtchn.vcpu_idx = vcpu->vcpu_idx;
1927 else
1928 e->xen_evtchn.vcpu_idx = -1;
1929
1930 e->xen_evtchn.port = ue->u.xen_evtchn.port;
1931 e->xen_evtchn.vcpu_id = ue->u.xen_evtchn.vcpu;
1932 e->xen_evtchn.priority = ue->u.xen_evtchn.priority;
1933 e->set = evtchn_set_fn;
1934
1935 return 0;
1936}
1937
1938/*
1939 * Explicit event sending from userspace with KVM_XEN_HVM_EVTCHN_SEND ioctl.
1940 */
1941int kvm_xen_hvm_evtchn_send(struct kvm *kvm, struct kvm_irq_routing_xen_evtchn *uxe)
1942{
1943 struct kvm_xen_evtchn e;
1944 int ret;
1945
1946 if (!uxe->port || uxe->port >= max_evtchn_port(kvm))
1947 return -EINVAL;
1948
1949 /* We only support 2 level event channels for now */
1950 if (uxe->priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
1951 return -EINVAL;
1952
1953 e.port = uxe->port;
1954 e.vcpu_id = uxe->vcpu;
1955 e.vcpu_idx = -1;
1956 e.priority = uxe->priority;
1957
1958 ret = kvm_xen_set_evtchn(&e, kvm);
1959
1960 /*
1961 * None of that 'return 1 if it actually got delivered' nonsense.
1962 * We don't care if it was masked (-ENOTCONN) either.
1963 */
1964 if (ret > 0 || ret == -ENOTCONN)
1965 ret = 0;
1966
1967 return ret;
1968}
1969
1970/*
1971 * Support for *outbound* event channel events via the EVTCHNOP_send hypercall.
1972 */
1973struct evtchnfd {
1974 u32 send_port;
1975 u32 type;
1976 union {
1977 struct kvm_xen_evtchn port;
1978 struct {
1979 u32 port; /* zero */
1980 struct eventfd_ctx *ctx;
1981 } eventfd;
1982 } deliver;
1983};
1984
1985/*
1986 * Update target vCPU or priority for a registered sending channel.
1987 */
1988static int kvm_xen_eventfd_update(struct kvm *kvm,
1989 struct kvm_xen_hvm_attr *data)
1990{
1991 u32 port = data->u.evtchn.send_port;
1992 struct evtchnfd *evtchnfd;
1993 int ret;
1994
1995 /* Protect writes to evtchnfd as well as the idr lookup. */
1996 mutex_lock(&kvm->arch.xen.xen_lock);
1997 evtchnfd = idr_find(&kvm->arch.xen.evtchn_ports, port);
1998
1999 ret = -ENOENT;
2000 if (!evtchnfd)
2001 goto out_unlock;
2002
2003 /* For an UPDATE, nothing may change except the priority/vcpu */
2004 ret = -EINVAL;
2005 if (evtchnfd->type != data->u.evtchn.type)
2006 goto out_unlock;
2007
2008 /*
2009 * Port cannot change, and if it's zero that was an eventfd
2010 * which can't be changed either.
2011 */
2012 if (!evtchnfd->deliver.port.port ||
2013 evtchnfd->deliver.port.port != data->u.evtchn.deliver.port.port)
2014 goto out_unlock;
2015
2016 /* We only support 2 level event channels for now */
2017 if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
2018 goto out_unlock;
2019
2020 evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
2021 if (evtchnfd->deliver.port.vcpu_id != data->u.evtchn.deliver.port.vcpu) {
2022 evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
2023 evtchnfd->deliver.port.vcpu_idx = -1;
2024 }
2025 ret = 0;
2026out_unlock:
2027 mutex_unlock(&kvm->arch.xen.xen_lock);
2028 return ret;
2029}
2030
2031/*
2032 * Configure the target (eventfd or local port delivery) for sending on
2033 * a given event channel.
2034 */
2035static int kvm_xen_eventfd_assign(struct kvm *kvm,
2036 struct kvm_xen_hvm_attr *data)
2037{
2038 u32 port = data->u.evtchn.send_port;
2039 struct eventfd_ctx *eventfd = NULL;
2040 struct evtchnfd *evtchnfd;
2041 int ret = -EINVAL;
2042
2043 evtchnfd = kzalloc(sizeof(struct evtchnfd), GFP_KERNEL);
2044 if (!evtchnfd)
2045 return -ENOMEM;
2046
2047 switch(data->u.evtchn.type) {
2048 case EVTCHNSTAT_ipi:
2049 /* IPI must map back to the same port# */
2050 if (data->u.evtchn.deliver.port.port != data->u.evtchn.send_port)
2051 goto out_noeventfd; /* -EINVAL */
2052 break;
2053
2054 case EVTCHNSTAT_interdomain:
2055 if (data->u.evtchn.deliver.port.port) {
2056 if (data->u.evtchn.deliver.port.port >= max_evtchn_port(kvm))
2057 goto out_noeventfd; /* -EINVAL */
2058 } else {
2059 eventfd = eventfd_ctx_fdget(data->u.evtchn.deliver.eventfd.fd);
2060 if (IS_ERR(eventfd)) {
2061 ret = PTR_ERR(eventfd);
2062 goto out_noeventfd;
2063 }
2064 }
2065 break;
2066
2067 case EVTCHNSTAT_virq:
2068 case EVTCHNSTAT_closed:
2069 case EVTCHNSTAT_unbound:
2070 case EVTCHNSTAT_pirq:
2071 default: /* Unknown event channel type */
2072 goto out; /* -EINVAL */
2073 }
2074
2075 evtchnfd->send_port = data->u.evtchn.send_port;
2076 evtchnfd->type = data->u.evtchn.type;
2077 if (eventfd) {
2078 evtchnfd->deliver.eventfd.ctx = eventfd;
2079 } else {
2080 /* We only support 2 level event channels for now */
2081 if (data->u.evtchn.deliver.port.priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
2082 goto out; /* -EINVAL; */
2083
2084 evtchnfd->deliver.port.port = data->u.evtchn.deliver.port.port;
2085 evtchnfd->deliver.port.vcpu_id = data->u.evtchn.deliver.port.vcpu;
2086 evtchnfd->deliver.port.vcpu_idx = -1;
2087 evtchnfd->deliver.port.priority = data->u.evtchn.deliver.port.priority;
2088 }
2089
2090 mutex_lock(&kvm->arch.xen.xen_lock);
2091 ret = idr_alloc(&kvm->arch.xen.evtchn_ports, evtchnfd, port, port + 1,
2092 GFP_KERNEL);
2093 mutex_unlock(&kvm->arch.xen.xen_lock);
2094 if (ret >= 0)
2095 return 0;
2096
2097 if (ret == -ENOSPC)
2098 ret = -EEXIST;
2099out:
2100 if (eventfd)
2101 eventfd_ctx_put(eventfd);
2102out_noeventfd:
2103 kfree(evtchnfd);
2104 return ret;
2105}
2106
2107static int kvm_xen_eventfd_deassign(struct kvm *kvm, u32 port)
2108{
2109 struct evtchnfd *evtchnfd;
2110
2111 mutex_lock(&kvm->arch.xen.xen_lock);
2112 evtchnfd = idr_remove(&kvm->arch.xen.evtchn_ports, port);
2113 mutex_unlock(&kvm->arch.xen.xen_lock);
2114
2115 if (!evtchnfd)
2116 return -ENOENT;
2117
2118 synchronize_srcu(&kvm->srcu);
2119 if (!evtchnfd->deliver.port.port)
2120 eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
2121 kfree(evtchnfd);
2122 return 0;
2123}
2124
2125static int kvm_xen_eventfd_reset(struct kvm *kvm)
2126{
2127 struct evtchnfd *evtchnfd, **all_evtchnfds;
2128 int i;
2129 int n = 0;
2130
2131 mutex_lock(&kvm->arch.xen.xen_lock);
2132
2133 /*
2134 * Because synchronize_srcu() cannot be called inside the
2135 * critical section, first collect all the evtchnfd objects
2136 * in an array as they are removed from evtchn_ports.
2137 */
2138 idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i)
2139 n++;
2140
2141 all_evtchnfds = kmalloc_array(n, sizeof(struct evtchnfd *), GFP_KERNEL);
2142 if (!all_evtchnfds) {
2143 mutex_unlock(&kvm->arch.xen.xen_lock);
2144 return -ENOMEM;
2145 }
2146
2147 n = 0;
2148 idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
2149 all_evtchnfds[n++] = evtchnfd;
2150 idr_remove(&kvm->arch.xen.evtchn_ports, evtchnfd->send_port);
2151 }
2152 mutex_unlock(&kvm->arch.xen.xen_lock);
2153
2154 synchronize_srcu(&kvm->srcu);
2155
2156 while (n--) {
2157 evtchnfd = all_evtchnfds[n];
2158 if (!evtchnfd->deliver.port.port)
2159 eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
2160 kfree(evtchnfd);
2161 }
2162 kfree(all_evtchnfds);
2163
2164 return 0;
2165}
2166
2167static int kvm_xen_setattr_evtchn(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
2168{
2169 u32 port = data->u.evtchn.send_port;
2170
2171 if (data->u.evtchn.flags == KVM_XEN_EVTCHN_RESET)
2172 return kvm_xen_eventfd_reset(kvm);
2173
2174 if (!port || port >= max_evtchn_port(kvm))
2175 return -EINVAL;
2176
2177 if (data->u.evtchn.flags == KVM_XEN_EVTCHN_DEASSIGN)
2178 return kvm_xen_eventfd_deassign(kvm, port);
2179 if (data->u.evtchn.flags == KVM_XEN_EVTCHN_UPDATE)
2180 return kvm_xen_eventfd_update(kvm, data);
2181 if (data->u.evtchn.flags)
2182 return -EINVAL;
2183
2184 return kvm_xen_eventfd_assign(kvm, data);
2185}
2186
2187static bool kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, u64 param, u64 *r)
2188{
2189 struct evtchnfd *evtchnfd;
2190 struct evtchn_send send;
2191 struct x86_exception e;
2192
2193 /* Sanity check: this structure is the same for 32-bit and 64-bit */
2194 BUILD_BUG_ON(sizeof(send) != 4);
2195 if (kvm_read_guest_virt(vcpu, param, &send, sizeof(send), &e)) {
2196 *r = -EFAULT;
2197 return true;
2198 }
2199
2200 /*
2201 * evtchnfd is protected by kvm->srcu; the idr lookup instead
2202 * is protected by RCU.
2203 */
2204 rcu_read_lock();
2205 evtchnfd = idr_find(&vcpu->kvm->arch.xen.evtchn_ports, send.port);
2206 rcu_read_unlock();
2207 if (!evtchnfd)
2208 return false;
2209
2210 if (evtchnfd->deliver.port.port) {
2211 int ret = kvm_xen_set_evtchn(&evtchnfd->deliver.port, vcpu->kvm);
2212 if (ret < 0 && ret != -ENOTCONN)
2213 return false;
2214 } else {
2215 eventfd_signal(evtchnfd->deliver.eventfd.ctx);
2216 }
2217
2218 *r = 0;
2219 return true;
2220}
2221
2222void kvm_xen_init_vcpu(struct kvm_vcpu *vcpu)
2223{
2224 vcpu->arch.xen.vcpu_id = vcpu->vcpu_idx;
2225 vcpu->arch.xen.poll_evtchn = 0;
2226
2227 timer_setup(&vcpu->arch.xen.poll_timer, cancel_evtchn_poll, 0);
2228 hrtimer_init(&vcpu->arch.xen.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
2229 vcpu->arch.xen.timer.function = xen_timer_callback;
2230
2231 kvm_gpc_init(&vcpu->arch.xen.runstate_cache, vcpu->kvm);
2232 kvm_gpc_init(&vcpu->arch.xen.runstate2_cache, vcpu->kvm);
2233 kvm_gpc_init(&vcpu->arch.xen.vcpu_info_cache, vcpu->kvm);
2234 kvm_gpc_init(&vcpu->arch.xen.vcpu_time_info_cache, vcpu->kvm);
2235}
2236
2237void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
2238{
2239 if (kvm_xen_timer_enabled(vcpu))
2240 kvm_xen_stop_timer(vcpu);
2241
2242 kvm_gpc_deactivate(&vcpu->arch.xen.runstate_cache);
2243 kvm_gpc_deactivate(&vcpu->arch.xen.runstate2_cache);
2244 kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_info_cache);
2245 kvm_gpc_deactivate(&vcpu->arch.xen.vcpu_time_info_cache);
2246
2247 del_timer_sync(&vcpu->arch.xen.poll_timer);
2248}
2249
2250void kvm_xen_update_tsc_info(struct kvm_vcpu *vcpu)
2251{
2252 struct kvm_cpuid_entry2 *entry;
2253 u32 function;
2254
2255 if (!vcpu->arch.xen.cpuid.base)
2256 return;
2257
2258 function = vcpu->arch.xen.cpuid.base | XEN_CPUID_LEAF(3);
2259 if (function > vcpu->arch.xen.cpuid.limit)
2260 return;
2261
2262 entry = kvm_find_cpuid_entry_index(vcpu, function, 1);
2263 if (entry) {
2264 entry->ecx = vcpu->arch.hv_clock.tsc_to_system_mul;
2265 entry->edx = vcpu->arch.hv_clock.tsc_shift;
2266 }
2267
2268 entry = kvm_find_cpuid_entry_index(vcpu, function, 2);
2269 if (entry)
2270 entry->eax = vcpu->arch.hw_tsc_khz;
2271}
2272
2273void kvm_xen_init_vm(struct kvm *kvm)
2274{
2275 mutex_init(&kvm->arch.xen.xen_lock);
2276 idr_init(&kvm->arch.xen.evtchn_ports);
2277 kvm_gpc_init(&kvm->arch.xen.shinfo_cache, kvm);
2278}
2279
2280void kvm_xen_destroy_vm(struct kvm *kvm)
2281{
2282 struct evtchnfd *evtchnfd;
2283 int i;
2284
2285 kvm_gpc_deactivate(&kvm->arch.xen.shinfo_cache);
2286
2287 idr_for_each_entry(&kvm->arch.xen.evtchn_ports, evtchnfd, i) {
2288 if (!evtchnfd->deliver.port.port)
2289 eventfd_ctx_put(evtchnfd->deliver.eventfd.ctx);
2290 kfree(evtchnfd);
2291 }
2292 idr_destroy(&kvm->arch.xen.evtchn_ports);
2293
2294 if (kvm->arch.xen_hvm_config.msr)
2295 static_branch_slow_dec_deferred(&kvm_xen_enabled);
2296}