blob: 10df100c4514e856d1ca5509f87f118e37726f57 [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
83 use_mm(mm);
84 down_read(&mm->mmap_sem);
chai wenf2e10662013-10-14 22:22:33 +080085 get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL);
Gleb Natapovaf585b92010-10-14 11:22:46 +020086 up_read(&mm->mmap_sem);
Dominik Dingele0ead412013-06-06 15:32:37 +020087 kvm_async_page_present_sync(vcpu, apf);
Gleb Natapovaf585b92010-10-14 11:22:46 +020088 unuse_mm(mm);
89
90 spin_lock(&vcpu->async_pf.lock);
91 list_add_tail(&apf->link, &vcpu->async_pf.done);
Gleb Natapovaf585b92010-10-14 11:22:46 +020092 spin_unlock(&vcpu->async_pf.lock);
93
94 /*
95 * apf may be freed by kvm_check_async_pf_completion() after
96 * this point
97 */
98
chai wenf2e10662013-10-14 22:22:33 +080099 trace_kvm_async_pf_completed(addr, gva);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200100
101 if (waitqueue_active(&vcpu->wq))
102 wake_up_interruptible(&vcpu->wq);
103
104 mmdrop(mm);
105 kvm_put_kvm(vcpu->kvm);
106}
107
108void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
109{
110 /* cancel outstanding work queue item */
111 while (!list_empty(&vcpu->async_pf.queue)) {
112 struct kvm_async_pf *work =
113 list_entry(vcpu->async_pf.queue.next,
114 typeof(*work), queue);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200115 list_del(&work->queue);
Dominik Dingel9f2ceda2013-09-03 12:31:16 +0200116
117#ifdef CONFIG_KVM_ASYNC_PF_SYNC
118 flush_work(&work->work);
119#else
Radim Krčmář98fda162013-09-04 22:32:24 +0200120 if (cancel_work_sync(&work->work)) {
Radim Krčmář28b441e2013-09-04 22:32:23 +0200121 mmdrop(work->mm);
122 kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */
Gleb Natapovaf585b92010-10-14 11:22:46 +0200123 kmem_cache_free(async_pf_cache, work);
Radim Krčmář28b441e2013-09-04 22:32:23 +0200124 }
Dominik Dingel9f2ceda2013-09-03 12:31:16 +0200125#endif
Gleb Natapovaf585b92010-10-14 11:22:46 +0200126 }
127
128 spin_lock(&vcpu->async_pf.lock);
129 while (!list_empty(&vcpu->async_pf.done)) {
130 struct kvm_async_pf *work =
131 list_entry(vcpu->async_pf.done.next,
132 typeof(*work), link);
133 list_del(&work->link);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200134 kmem_cache_free(async_pf_cache, work);
135 }
136 spin_unlock(&vcpu->async_pf.lock);
137
138 vcpu->async_pf.queued = 0;
139}
140
141void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
142{
143 struct kvm_async_pf *work;
144
Xiao Guangrong15096ff2010-11-02 17:35:35 +0800145 while (!list_empty_careful(&vcpu->async_pf.done) &&
146 kvm_arch_can_inject_async_page_present(vcpu)) {
147 spin_lock(&vcpu->async_pf.lock);
148 work = list_first_entry(&vcpu->async_pf.done, typeof(*work),
149 link);
150 list_del(&work->link);
151 spin_unlock(&vcpu->async_pf.lock);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200152
chai wenf2e10662013-10-14 22:22:33 +0800153 kvm_arch_async_page_ready(vcpu, work);
Dominik Dingel1179ba52014-01-31 14:32:46 +0100154 kvm_async_page_present_async(vcpu, work);
Gleb Natapovaf585b92010-10-14 11:22:46 +0200155
Xiao Guangrong15096ff2010-11-02 17:35:35 +0800156 list_del(&work->queue);
157 vcpu->async_pf.queued--;
Xiao Guangrong15096ff2010-11-02 17:35:35 +0800158 kmem_cache_free(async_pf_cache, work);
159 }
Gleb Natapovaf585b92010-10-14 11:22:46 +0200160}
161
Dominik Dingele0ead412013-06-06 15:32:37 +0200162int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
Gleb Natapovaf585b92010-10-14 11:22:46 +0200163 struct kvm_arch_async_pf *arch)
164{
165 struct kvm_async_pf *work;
166
167 if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
168 return 0;
169
170 /* setup delayed work */
171
172 /*
173 * do alloc nowait since if we are going to sleep anyway we
174 * may as well sleep faulting in page
175 */
176 work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT);
177 if (!work)
178 return 0;
179
chai wenf2e10662013-10-14 22:22:33 +0800180 work->wakeup_all = false;
Gleb Natapovaf585b92010-10-14 11:22:46 +0200181 work->vcpu = vcpu;
182 work->gva = gva;
Dominik Dingele0ead412013-06-06 15:32:37 +0200183 work->addr = hva;
Gleb Natapovaf585b92010-10-14 11:22:46 +0200184 work->arch = *arch;
185 work->mm = current->mm;
186 atomic_inc(&work->mm->mm_count);
187 kvm_get_kvm(work->vcpu->kvm);
188
189 /* this can't really happen otherwise gfn_to_pfn_async
190 would succeed */
191 if (unlikely(kvm_is_error_hva(work->addr)))
192 goto retry_sync;
193
194 INIT_WORK(&work->work, async_pf_execute);
195 if (!schedule_work(&work->work))
196 goto retry_sync;
197
198 list_add_tail(&work->queue, &vcpu->async_pf.queue);
199 vcpu->async_pf.queued++;
200 kvm_arch_async_page_not_present(vcpu, work);
201 return 1;
202retry_sync:
203 kvm_put_kvm(work->vcpu->kvm);
204 mmdrop(work->mm);
205 kmem_cache_free(async_pf_cache, work);
206 return 0;
207}
Gleb Natapov344d9582010-10-14 11:22:50 +0200208
209int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
210{
211 struct kvm_async_pf *work;
212
Xiao Guangrong64f638c2010-11-01 17:03:44 +0800213 if (!list_empty_careful(&vcpu->async_pf.done))
Gleb Natapov344d9582010-10-14 11:22:50 +0200214 return 0;
215
216 work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
217 if (!work)
218 return -ENOMEM;
219
chai wenf2e10662013-10-14 22:22:33 +0800220 work->wakeup_all = true;
Gleb Natapov344d9582010-10-14 11:22:50 +0200221 INIT_LIST_HEAD(&work->queue); /* for list_del to work */
222
Xiao Guangrong64f638c2010-11-01 17:03:44 +0800223 spin_lock(&vcpu->async_pf.lock);
Gleb Natapov344d9582010-10-14 11:22:50 +0200224 list_add_tail(&work->link, &vcpu->async_pf.done);
Xiao Guangrong64f638c2010-11-01 17:03:44 +0800225 spin_unlock(&vcpu->async_pf.lock);
226
Gleb Natapov344d9582010-10-14 11:22:50 +0200227 vcpu->async_pf.queued++;
228 return 0;
229}