blob: 35315992245600a418874fd371e641ef336a0a22 [file] [log] [blame]
Gleb Natapovaf585b92010-10-14 11:22:46 +02001/*
2 * kvm asynchronous fault support
3 *
4 * Copyright 2010 Red Hat, Inc.
5 *
6 * Author:
7 * Gleb Natapov <gleb@redhat.com>
8 *
9 * This file is free software; you can redistribute it and/or modify
10 * it under the terms of version 2 of the GNU General Public License
11 * as published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
21 */
22
23#include <linux/kvm_host.h>
24#include <linux/slab.h>
25#include <linux/module.h>
26#include <linux/mmu_context.h>
27
28#include "async_pf.h"
29#include <trace/events/kvm.h>
30
Dominik Dingele0ead412013-06-06 15:32:37 +020031static inline void kvm_async_page_present_sync(struct kvm_vcpu *vcpu,
32 struct kvm_async_pf *work)
33{
34#ifdef CONFIG_KVM_ASYNC_PF_SYNC
35 kvm_arch_async_page_present(vcpu, work);
36#endif
37}
38static inline void kvm_async_page_present_async(struct kvm_vcpu *vcpu,
39 struct kvm_async_pf *work)
40{
41#ifndef CONFIG_KVM_ASYNC_PF_SYNC
42 kvm_arch_async_page_present(vcpu, work);
43#endif
44}
45
Gleb Natapovaf585b92010-10-14 11:22:46 +020046static struct kmem_cache *async_pf_cache;
47
48int kvm_async_pf_init(void)
49{
50 async_pf_cache = KMEM_CACHE(kvm_async_pf, 0);
51
52 if (!async_pf_cache)
53 return -ENOMEM;
54
55 return 0;
56}
57
58void kvm_async_pf_deinit(void)
59{
Markus Elfring4f526962015-11-15 10:40:36 +010060 kmem_cache_destroy(async_pf_cache);
Gleb Natapovaf585b92010-10-14 11:22:46 +020061 async_pf_cache = NULL;
62}
63
64void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
65{
66 INIT_LIST_HEAD(&vcpu->async_pf.done);
67 INIT_LIST_HEAD(&vcpu->async_pf.queue);
68 spin_lock_init(&vcpu->async_pf.lock);
69}
70
71static void async_pf_execute(struct work_struct *work)
72{
Gleb Natapovaf585b92010-10-14 11:22:46 +020073 struct kvm_async_pf *apf =
74 container_of(work, struct kvm_async_pf, work);
75 struct mm_struct *mm = apf->mm;
76 struct kvm_vcpu *vcpu = apf->vcpu;
77 unsigned long addr = apf->addr;
78 gva_t gva = apf->gva;
79
80 might_sleep();
81
Andrea Arcangeli0664e572015-02-11 15:27:28 -080082 get_user_pages_unlocked(NULL, mm, addr, 1, 1, 0, NULL);
Dominik Dingele0ead412013-06-06 15:32:37 +020083 kvm_async_page_present_sync(vcpu, apf);
Gleb Natapovaf585b92010-10-14 11:22:46 +020084
85 spin_lock(&vcpu->async_pf.lock);
86 list_add_tail(&apf->link, &vcpu->async_pf.done);
Gleb Natapovaf585b92010-10-14 11:22:46 +020087 spin_unlock(&vcpu->async_pf.lock);
88
89 /*
90 * apf may be freed by kvm_check_async_pf_completion() after
91 * this point
92 */
93
chai wenf2e10662013-10-14 22:22:33 +080094 trace_kvm_async_pf_completed(addr, gva);
Gleb Natapovaf585b92010-10-14 11:22:46 +020095
Kosuke Tatsukawa6003a422015-10-09 12:21:55 +000096 /*
97 * This memory barrier pairs with prepare_to_wait's set_current_state()
98 */
99 smp_mb();
Gleb Natapovaf585b92010-10-14 11:22:46 +0200100 if (waitqueue_active(&vcpu->wq))
101 wake_up_interruptible(&vcpu->wq);
102
Oleg Nesterov41c22f62014-04-21 15:26:01 +0200103 mmput(mm);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200104 kvm_put_kvm(vcpu->kvm);
105}
106
107void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
108{
109 /* cancel outstanding work queue item */
110 while (!list_empty(&vcpu->async_pf.queue)) {
111 struct kvm_async_pf *work =
112 list_entry(vcpu->async_pf.queue.next,
113 typeof(*work), queue);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200114 list_del(&work->queue);
Dominik Dingel9f2ceda2013-09-03 12:31:16 +0200115
116#ifdef CONFIG_KVM_ASYNC_PF_SYNC
117 flush_work(&work->work);
118#else
Radim Krčmář98fda162013-09-04 22:32:24 +0200119 if (cancel_work_sync(&work->work)) {
Oleg Nesterov41c22f62014-04-21 15:26:01 +0200120 mmput(work->mm);
Radim Krčmář28b441e2013-09-04 22:32:23 +0200121 kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */
Gleb Natapovaf585b92010-10-14 11:22:46 +0200122 kmem_cache_free(async_pf_cache, work);
Radim Krčmář28b441e2013-09-04 22:32:23 +0200123 }
Dominik Dingel9f2ceda2013-09-03 12:31:16 +0200124#endif
Gleb Natapovaf585b92010-10-14 11:22:46 +0200125 }
126
127 spin_lock(&vcpu->async_pf.lock);
128 while (!list_empty(&vcpu->async_pf.done)) {
129 struct kvm_async_pf *work =
130 list_entry(vcpu->async_pf.done.next,
131 typeof(*work), link);
132 list_del(&work->link);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200133 kmem_cache_free(async_pf_cache, work);
134 }
135 spin_unlock(&vcpu->async_pf.lock);
136
137 vcpu->async_pf.queued = 0;
138}
139
140void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
141{
142 struct kvm_async_pf *work;
143
Xiao Guangrong15096ff2010-11-02 17:35:35 +0800144 while (!list_empty_careful(&vcpu->async_pf.done) &&
145 kvm_arch_can_inject_async_page_present(vcpu)) {
146 spin_lock(&vcpu->async_pf.lock);
147 work = list_first_entry(&vcpu->async_pf.done, typeof(*work),
148 link);
149 list_del(&work->link);
150 spin_unlock(&vcpu->async_pf.lock);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200151
chai wenf2e10662013-10-14 22:22:33 +0800152 kvm_arch_async_page_ready(vcpu, work);
Dominik Dingel1179ba52014-01-31 14:32:46 +0100153 kvm_async_page_present_async(vcpu, work);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200154
Xiao Guangrong15096ff2010-11-02 17:35:35 +0800155 list_del(&work->queue);
156 vcpu->async_pf.queued--;
Xiao Guangrong15096ff2010-11-02 17:35:35 +0800157 kmem_cache_free(async_pf_cache, work);
158 }
Gleb Natapovaf585b92010-10-14 11:22:46 +0200159}
160
Dominik Dingele0ead412013-06-06 15:32:37 +0200161int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
Gleb Natapovaf585b92010-10-14 11:22:46 +0200162 struct kvm_arch_async_pf *arch)
163{
164 struct kvm_async_pf *work;
165
166 if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
167 return 0;
168
169 /* setup delayed work */
170
171 /*
172 * do alloc nowait since if we are going to sleep anyway we
173 * may as well sleep faulting in page
174 */
175 work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT);
176 if (!work)
177 return 0;
178
chai wenf2e10662013-10-14 22:22:33 +0800179 work->wakeup_all = false;
Gleb Natapovaf585b92010-10-14 11:22:46 +0200180 work->vcpu = vcpu;
181 work->gva = gva;
Dominik Dingele0ead412013-06-06 15:32:37 +0200182 work->addr = hva;
Gleb Natapovaf585b92010-10-14 11:22:46 +0200183 work->arch = *arch;
184 work->mm = current->mm;
Oleg Nesterov41c22f62014-04-21 15:26:01 +0200185 atomic_inc(&work->mm->mm_users);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200186 kvm_get_kvm(work->vcpu->kvm);
187
188 /* this can't really happen otherwise gfn_to_pfn_async
189 would succeed */
190 if (unlikely(kvm_is_error_hva(work->addr)))
191 goto retry_sync;
192
193 INIT_WORK(&work->work, async_pf_execute);
194 if (!schedule_work(&work->work))
195 goto retry_sync;
196
197 list_add_tail(&work->queue, &vcpu->async_pf.queue);
198 vcpu->async_pf.queued++;
199 kvm_arch_async_page_not_present(vcpu, work);
200 return 1;
201retry_sync:
202 kvm_put_kvm(work->vcpu->kvm);
Oleg Nesterov41c22f62014-04-21 15:26:01 +0200203 mmput(work->mm);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200204 kmem_cache_free(async_pf_cache, work);
205 return 0;
206}
Gleb Natapov344d9582010-10-14 11:22:50 +0200207
208int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
209{
210 struct kvm_async_pf *work;
211
Xiao Guangrong64f638c2010-11-01 17:03:44 +0800212 if (!list_empty_careful(&vcpu->async_pf.done))
Gleb Natapov344d9582010-10-14 11:22:50 +0200213 return 0;
214
215 work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
216 if (!work)
217 return -ENOMEM;
218
chai wenf2e10662013-10-14 22:22:33 +0800219 work->wakeup_all = true;
Gleb Natapov344d9582010-10-14 11:22:50 +0200220 INIT_LIST_HEAD(&work->queue); /* for list_del to work */
221
Xiao Guangrong64f638c2010-11-01 17:03:44 +0800222 spin_lock(&vcpu->async_pf.lock);
Gleb Natapov344d9582010-10-14 11:22:50 +0200223 list_add_tail(&work->link, &vcpu->async_pf.done);
Xiao Guangrong64f638c2010-11-01 17:03:44 +0800224 spin_unlock(&vcpu->async_pf.lock);
225
Gleb Natapov344d9582010-10-14 11:22:50 +0200226 vcpu->async_pf.queued++;
227 return 0;
228}