blob: d6a3d0993d8812c8527274d01e8c08ce942746a4 [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{
60 if (async_pf_cache)
61 kmem_cache_destroy(async_pf_cache);
62 async_pf_cache = NULL;
63}
64
65void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
66{
67 INIT_LIST_HEAD(&vcpu->async_pf.done);
68 INIT_LIST_HEAD(&vcpu->async_pf.queue);
69 spin_lock_init(&vcpu->async_pf.lock);
70}
71
72static void async_pf_execute(struct work_struct *work)
73{
Gleb Natapovaf585b92010-10-14 11:22:46 +020074 struct kvm_async_pf *apf =
75 container_of(work, struct kvm_async_pf, work);
76 struct mm_struct *mm = apf->mm;
77 struct kvm_vcpu *vcpu = apf->vcpu;
78 unsigned long addr = apf->addr;
79 gva_t gva = apf->gva;
80
81 might_sleep();
82
Gleb Natapovaf585b92010-10-14 11:22:46 +020083 down_read(&mm->mmap_sem);
Oleg Nesterove9545b92014-04-28 17:03:00 +020084 get_user_pages(NULL, mm, addr, 1, 1, 0, NULL, NULL);
Gleb Natapovaf585b92010-10-14 11:22:46 +020085 up_read(&mm->mmap_sem);
Dominik Dingele0ead412013-06-06 15:32:37 +020086 kvm_async_page_present_sync(vcpu, apf);
Gleb Natapovaf585b92010-10-14 11:22:46 +020087
88 spin_lock(&vcpu->async_pf.lock);
89 list_add_tail(&apf->link, &vcpu->async_pf.done);
Gleb Natapovaf585b92010-10-14 11:22:46 +020090 spin_unlock(&vcpu->async_pf.lock);
91
92 /*
93 * apf may be freed by kvm_check_async_pf_completion() after
94 * this point
95 */
96
chai wenf2e10662013-10-14 22:22:33 +080097 trace_kvm_async_pf_completed(addr, gva);
Gleb Natapovaf585b92010-10-14 11:22:46 +020098
99 if (waitqueue_active(&vcpu->wq))
100 wake_up_interruptible(&vcpu->wq);
101
Oleg Nesterov41c22f62014-04-21 15:26:01 +0200102 mmput(mm);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200103 kvm_put_kvm(vcpu->kvm);
104}
105
106void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
107{
108 /* cancel outstanding work queue item */
109 while (!list_empty(&vcpu->async_pf.queue)) {
110 struct kvm_async_pf *work =
111 list_entry(vcpu->async_pf.queue.next,
112 typeof(*work), queue);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200113 list_del(&work->queue);
Dominik Dingel9f2ceda2013-09-03 12:31:16 +0200114
115#ifdef CONFIG_KVM_ASYNC_PF_SYNC
116 flush_work(&work->work);
117#else
Radim Krčmář98fda162013-09-04 22:32:24 +0200118 if (cancel_work_sync(&work->work)) {
Oleg Nesterov41c22f62014-04-21 15:26:01 +0200119 mmput(work->mm);
Radim Krčmář28b441e2013-09-04 22:32:23 +0200120 kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */
Gleb Natapovaf585b92010-10-14 11:22:46 +0200121 kmem_cache_free(async_pf_cache, work);
Radim Krčmář28b441e2013-09-04 22:32:23 +0200122 }
Dominik Dingel9f2ceda2013-09-03 12:31:16 +0200123#endif
Gleb Natapovaf585b92010-10-14 11:22:46 +0200124 }
125
126 spin_lock(&vcpu->async_pf.lock);
127 while (!list_empty(&vcpu->async_pf.done)) {
128 struct kvm_async_pf *work =
129 list_entry(vcpu->async_pf.done.next,
130 typeof(*work), link);
131 list_del(&work->link);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200132 kmem_cache_free(async_pf_cache, work);
133 }
134 spin_unlock(&vcpu->async_pf.lock);
135
136 vcpu->async_pf.queued = 0;
137}
138
139void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
140{
141 struct kvm_async_pf *work;
142
Xiao Guangrong15096ff2010-11-02 17:35:35 +0800143 while (!list_empty_careful(&vcpu->async_pf.done) &&
144 kvm_arch_can_inject_async_page_present(vcpu)) {
145 spin_lock(&vcpu->async_pf.lock);
146 work = list_first_entry(&vcpu->async_pf.done, typeof(*work),
147 link);
148 list_del(&work->link);
149 spin_unlock(&vcpu->async_pf.lock);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200150
chai wenf2e10662013-10-14 22:22:33 +0800151 kvm_arch_async_page_ready(vcpu, work);
Dominik Dingel1179ba52014-01-31 14:32:46 +0100152 kvm_async_page_present_async(vcpu, work);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200153
Xiao Guangrong15096ff2010-11-02 17:35:35 +0800154 list_del(&work->queue);
155 vcpu->async_pf.queued--;
Xiao Guangrong15096ff2010-11-02 17:35:35 +0800156 kmem_cache_free(async_pf_cache, work);
157 }
Gleb Natapovaf585b92010-10-14 11:22:46 +0200158}
159
Dominik Dingele0ead412013-06-06 15:32:37 +0200160int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
Gleb Natapovaf585b92010-10-14 11:22:46 +0200161 struct kvm_arch_async_pf *arch)
162{
163 struct kvm_async_pf *work;
164
165 if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
166 return 0;
167
168 /* setup delayed work */
169
170 /*
171 * do alloc nowait since if we are going to sleep anyway we
172 * may as well sleep faulting in page
173 */
174 work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT);
175 if (!work)
176 return 0;
177
chai wenf2e10662013-10-14 22:22:33 +0800178 work->wakeup_all = false;
Gleb Natapovaf585b92010-10-14 11:22:46 +0200179 work->vcpu = vcpu;
180 work->gva = gva;
Dominik Dingele0ead412013-06-06 15:32:37 +0200181 work->addr = hva;
Gleb Natapovaf585b92010-10-14 11:22:46 +0200182 work->arch = *arch;
183 work->mm = current->mm;
Oleg Nesterov41c22f62014-04-21 15:26:01 +0200184 atomic_inc(&work->mm->mm_users);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200185 kvm_get_kvm(work->vcpu->kvm);
186
187 /* this can't really happen otherwise gfn_to_pfn_async
188 would succeed */
189 if (unlikely(kvm_is_error_hva(work->addr)))
190 goto retry_sync;
191
192 INIT_WORK(&work->work, async_pf_execute);
193 if (!schedule_work(&work->work))
194 goto retry_sync;
195
196 list_add_tail(&work->queue, &vcpu->async_pf.queue);
197 vcpu->async_pf.queued++;
198 kvm_arch_async_page_not_present(vcpu, work);
199 return 1;
200retry_sync:
201 kvm_put_kvm(work->vcpu->kvm);
Oleg Nesterov41c22f62014-04-21 15:26:01 +0200202 mmput(work->mm);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200203 kmem_cache_free(async_pf_cache, work);
204 return 0;
205}
Gleb Natapov344d9582010-10-14 11:22:50 +0200206
207int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
208{
209 struct kvm_async_pf *work;
210
Xiao Guangrong64f638c2010-11-01 17:03:44 +0800211 if (!list_empty_careful(&vcpu->async_pf.done))
Gleb Natapov344d9582010-10-14 11:22:50 +0200212 return 0;
213
214 work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
215 if (!work)
216 return -ENOMEM;
217
chai wenf2e10662013-10-14 22:22:33 +0800218 work->wakeup_all = true;
Gleb Natapov344d9582010-10-14 11:22:50 +0200219 INIT_LIST_HEAD(&work->queue); /* for list_del to work */
220
Xiao Guangrong64f638c2010-11-01 17:03:44 +0800221 spin_lock(&vcpu->async_pf.lock);
Gleb Natapov344d9582010-10-14 11:22:50 +0200222 list_add_tail(&work->link, &vcpu->async_pf.done);
Xiao Guangrong64f638c2010-11-01 17:03:44 +0800223 spin_unlock(&vcpu->async_pf.lock);
224
Gleb Natapov344d9582010-10-14 11:22:50 +0200225 vcpu->async_pf.queued++;
226 return 0;
227}