Commit | Line | Data |
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af585b92 GN |
1 | /* |
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 | ||
e0ead41a DD |
31 | static 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 | } | |
38 | static 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 | ||
af585b92 GN |
46 | static struct kmem_cache *async_pf_cache; |
47 | ||
48 | int 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 | ||
58 | void kvm_async_pf_deinit(void) | |
59 | { | |
4f52696a | 60 | kmem_cache_destroy(async_pf_cache); |
af585b92 GN |
61 | async_pf_cache = NULL; |
62 | } | |
63 | ||
64 | void 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 | ||
71 | static void async_pf_execute(struct work_struct *work) | |
72 | { | |
af585b92 GN |
73 | 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 | ||
0664e57f | 82 | get_user_pages_unlocked(NULL, mm, addr, 1, 1, 0, NULL); |
e0ead41a | 83 | kvm_async_page_present_sync(vcpu, apf); |
af585b92 GN |
84 | |
85 | spin_lock(&vcpu->async_pf.lock); | |
86 | list_add_tail(&apf->link, &vcpu->async_pf.done); | |
af585b92 GN |
87 | 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 | ||
f2e10669 | 94 | trace_kvm_async_pf_completed(addr, gva); |
af585b92 | 95 | |
6003a420 KT |
96 | /* |
97 | * This memory barrier pairs with prepare_to_wait's set_current_state() | |
98 | */ | |
99 | smp_mb(); | |
af585b92 GN |
100 | if (waitqueue_active(&vcpu->wq)) |
101 | wake_up_interruptible(&vcpu->wq); | |
102 | ||
41c22f62 | 103 | mmput(mm); |
af585b92 GN |
104 | kvm_put_kvm(vcpu->kvm); |
105 | } | |
106 | ||
107 | void 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); | |
af585b92 | 114 | list_del(&work->queue); |
9f2ceda4 DD |
115 | |
116 | #ifdef CONFIG_KVM_ASYNC_PF_SYNC | |
117 | flush_work(&work->work); | |
118 | #else | |
98fda169 | 119 | if (cancel_work_sync(&work->work)) { |
41c22f62 | 120 | mmput(work->mm); |
28b441e2 | 121 | kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */ |
af585b92 | 122 | kmem_cache_free(async_pf_cache, work); |
28b441e2 | 123 | } |
9f2ceda4 | 124 | #endif |
af585b92 GN |
125 | } |
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); | |
af585b92 GN |
133 | kmem_cache_free(async_pf_cache, work); |
134 | } | |
135 | spin_unlock(&vcpu->async_pf.lock); | |
136 | ||
137 | vcpu->async_pf.queued = 0; | |
138 | } | |
139 | ||
140 | void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) | |
141 | { | |
142 | struct kvm_async_pf *work; | |
143 | ||
15096ffc XG |
144 | 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); | |
af585b92 | 151 | |
f2e10669 | 152 | kvm_arch_async_page_ready(vcpu, work); |
1179ba53 | 153 | kvm_async_page_present_async(vcpu, work); |
af585b92 | 154 | |
15096ffc XG |
155 | list_del(&work->queue); |
156 | vcpu->async_pf.queued--; | |
15096ffc XG |
157 | kmem_cache_free(async_pf_cache, work); |
158 | } | |
af585b92 GN |
159 | } |
160 | ||
e0ead41a | 161 | int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva, |
af585b92 GN |
162 | 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 | */ | |
d7444794 | 175 | work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT | __GFP_NOWARN); |
af585b92 GN |
176 | if (!work) |
177 | return 0; | |
178 | ||
f2e10669 | 179 | work->wakeup_all = false; |
af585b92 GN |
180 | work->vcpu = vcpu; |
181 | work->gva = gva; | |
e0ead41a | 182 | work->addr = hva; |
af585b92 GN |
183 | work->arch = *arch; |
184 | work->mm = current->mm; | |
41c22f62 | 185 | atomic_inc(&work->mm->mm_users); |
af585b92 GN |
186 | 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; | |
201 | retry_sync: | |
202 | kvm_put_kvm(work->vcpu->kvm); | |
41c22f62 | 203 | mmput(work->mm); |
af585b92 GN |
204 | kmem_cache_free(async_pf_cache, work); |
205 | return 0; | |
206 | } | |
344d9588 GN |
207 | |
208 | int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) | |
209 | { | |
210 | struct kvm_async_pf *work; | |
211 | ||
64f638c7 | 212 | if (!list_empty_careful(&vcpu->async_pf.done)) |
344d9588 GN |
213 | return 0; |
214 | ||
215 | work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); | |
216 | if (!work) | |
217 | return -ENOMEM; | |
218 | ||
f2e10669 | 219 | work->wakeup_all = true; |
344d9588 GN |
220 | INIT_LIST_HEAD(&work->queue); /* for list_del to work */ |
221 | ||
64f638c7 | 222 | spin_lock(&vcpu->async_pf.lock); |
344d9588 | 223 | list_add_tail(&work->link, &vcpu->async_pf.done); |
64f638c7 XG |
224 | spin_unlock(&vcpu->async_pf.lock); |
225 | ||
344d9588 GN |
226 | vcpu->async_pf.queued++; |
227 | return 0; | |
228 | } |