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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> | |
6e84f315 | 27 | #include <linux/sched/mm.h> |
af585b92 GN |
28 | |
29 | #include "async_pf.h" | |
30 | #include <trace/events/kvm.h> | |
31 | ||
e0ead41a DD |
32 | static inline void kvm_async_page_present_sync(struct kvm_vcpu *vcpu, |
33 | struct kvm_async_pf *work) | |
34 | { | |
35 | #ifdef CONFIG_KVM_ASYNC_PF_SYNC | |
36 | kvm_arch_async_page_present(vcpu, work); | |
37 | #endif | |
38 | } | |
39 | static inline void kvm_async_page_present_async(struct kvm_vcpu *vcpu, | |
40 | struct kvm_async_pf *work) | |
41 | { | |
42 | #ifndef CONFIG_KVM_ASYNC_PF_SYNC | |
43 | kvm_arch_async_page_present(vcpu, work); | |
44 | #endif | |
45 | } | |
46 | ||
af585b92 GN |
47 | static struct kmem_cache *async_pf_cache; |
48 | ||
49 | int kvm_async_pf_init(void) | |
50 | { | |
51 | async_pf_cache = KMEM_CACHE(kvm_async_pf, 0); | |
52 | ||
53 | if (!async_pf_cache) | |
54 | return -ENOMEM; | |
55 | ||
56 | return 0; | |
57 | } | |
58 | ||
59 | void kvm_async_pf_deinit(void) | |
60 | { | |
4f52696a | 61 | kmem_cache_destroy(async_pf_cache); |
af585b92 GN |
62 | async_pf_cache = NULL; |
63 | } | |
64 | ||
65 | void 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 | ||
72 | static void async_pf_execute(struct work_struct *work) | |
73 | { | |
af585b92 GN |
74 | 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; | |
8b7457ef | 80 | int locked = 1; |
af585b92 GN |
81 | |
82 | might_sleep(); | |
83 | ||
1e987790 DH |
84 | /* |
85 | * This work is run asynchromously to the task which owns | |
86 | * mm and might be done in another context, so we must | |
8b7457ef | 87 | * access remotely. |
1e987790 | 88 | */ |
8b7457ef LS |
89 | down_read(&mm->mmap_sem); |
90 | get_user_pages_remote(NULL, mm, addr, 1, FOLL_WRITE, NULL, NULL, | |
91 | &locked); | |
92 | if (locked) | |
93 | up_read(&mm->mmap_sem); | |
1e987790 | 94 | |
e0ead41a | 95 | kvm_async_page_present_sync(vcpu, apf); |
af585b92 GN |
96 | |
97 | spin_lock(&vcpu->async_pf.lock); | |
98 | list_add_tail(&apf->link, &vcpu->async_pf.done); | |
22583f0d | 99 | apf->vcpu = NULL; |
af585b92 GN |
100 | spin_unlock(&vcpu->async_pf.lock); |
101 | ||
102 | /* | |
103 | * apf may be freed by kvm_check_async_pf_completion() after | |
104 | * this point | |
105 | */ | |
106 | ||
f2e10669 | 107 | trace_kvm_async_pf_completed(addr, gva); |
af585b92 | 108 | |
b9f67a42 | 109 | if (swq_has_sleeper(&vcpu->wq)) |
8577370f | 110 | swake_up(&vcpu->wq); |
af585b92 | 111 | |
41c22f62 | 112 | mmput(mm); |
af585b92 GN |
113 | kvm_put_kvm(vcpu->kvm); |
114 | } | |
115 | ||
116 | void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) | |
117 | { | |
22583f0d PB |
118 | spin_lock(&vcpu->async_pf.lock); |
119 | ||
af585b92 GN |
120 | /* cancel outstanding work queue item */ |
121 | while (!list_empty(&vcpu->async_pf.queue)) { | |
122 | struct kvm_async_pf *work = | |
433da860 GT |
123 | list_first_entry(&vcpu->async_pf.queue, |
124 | typeof(*work), queue); | |
af585b92 | 125 | list_del(&work->queue); |
9f2ceda4 | 126 | |
22583f0d PB |
127 | /* |
128 | * We know it's present in vcpu->async_pf.done, do | |
129 | * nothing here. | |
130 | */ | |
131 | if (!work->vcpu) | |
132 | continue; | |
133 | ||
134 | spin_unlock(&vcpu->async_pf.lock); | |
9f2ceda4 DD |
135 | #ifdef CONFIG_KVM_ASYNC_PF_SYNC |
136 | flush_work(&work->work); | |
137 | #else | |
98fda169 | 138 | if (cancel_work_sync(&work->work)) { |
41c22f62 | 139 | mmput(work->mm); |
28b441e2 | 140 | kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */ |
af585b92 | 141 | kmem_cache_free(async_pf_cache, work); |
28b441e2 | 142 | } |
9f2ceda4 | 143 | #endif |
22583f0d | 144 | spin_lock(&vcpu->async_pf.lock); |
af585b92 GN |
145 | } |
146 | ||
af585b92 GN |
147 | while (!list_empty(&vcpu->async_pf.done)) { |
148 | struct kvm_async_pf *work = | |
433da860 GT |
149 | list_first_entry(&vcpu->async_pf.done, |
150 | typeof(*work), link); | |
af585b92 | 151 | list_del(&work->link); |
af585b92 GN |
152 | kmem_cache_free(async_pf_cache, work); |
153 | } | |
154 | spin_unlock(&vcpu->async_pf.lock); | |
155 | ||
156 | vcpu->async_pf.queued = 0; | |
157 | } | |
158 | ||
159 | void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) | |
160 | { | |
161 | struct kvm_async_pf *work; | |
162 | ||
15096ffc XG |
163 | while (!list_empty_careful(&vcpu->async_pf.done) && |
164 | kvm_arch_can_inject_async_page_present(vcpu)) { | |
165 | spin_lock(&vcpu->async_pf.lock); | |
166 | work = list_first_entry(&vcpu->async_pf.done, typeof(*work), | |
167 | link); | |
168 | list_del(&work->link); | |
169 | spin_unlock(&vcpu->async_pf.lock); | |
af585b92 | 170 | |
f2e10669 | 171 | kvm_arch_async_page_ready(vcpu, work); |
1179ba53 | 172 | kvm_async_page_present_async(vcpu, work); |
af585b92 | 173 | |
15096ffc XG |
174 | list_del(&work->queue); |
175 | vcpu->async_pf.queued--; | |
15096ffc XG |
176 | kmem_cache_free(async_pf_cache, work); |
177 | } | |
af585b92 GN |
178 | } |
179 | ||
e0ead41a | 180 | int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva, |
af585b92 GN |
181 | struct kvm_arch_async_pf *arch) |
182 | { | |
183 | struct kvm_async_pf *work; | |
184 | ||
185 | if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU) | |
186 | return 0; | |
187 | ||
188 | /* setup delayed work */ | |
189 | ||
190 | /* | |
191 | * do alloc nowait since if we are going to sleep anyway we | |
192 | * may as well sleep faulting in page | |
193 | */ | |
d7444794 | 194 | work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT | __GFP_NOWARN); |
af585b92 GN |
195 | if (!work) |
196 | return 0; | |
197 | ||
f2e10669 | 198 | work->wakeup_all = false; |
af585b92 GN |
199 | work->vcpu = vcpu; |
200 | work->gva = gva; | |
e0ead41a | 201 | work->addr = hva; |
af585b92 GN |
202 | work->arch = *arch; |
203 | work->mm = current->mm; | |
3fce371b | 204 | mmget(work->mm); |
af585b92 GN |
205 | kvm_get_kvm(work->vcpu->kvm); |
206 | ||
207 | /* this can't really happen otherwise gfn_to_pfn_async | |
208 | would succeed */ | |
209 | if (unlikely(kvm_is_error_hva(work->addr))) | |
210 | goto retry_sync; | |
211 | ||
212 | INIT_WORK(&work->work, async_pf_execute); | |
213 | if (!schedule_work(&work->work)) | |
214 | goto retry_sync; | |
215 | ||
216 | list_add_tail(&work->queue, &vcpu->async_pf.queue); | |
217 | vcpu->async_pf.queued++; | |
218 | kvm_arch_async_page_not_present(vcpu, work); | |
219 | return 1; | |
220 | retry_sync: | |
221 | kvm_put_kvm(work->vcpu->kvm); | |
41c22f62 | 222 | mmput(work->mm); |
af585b92 GN |
223 | kmem_cache_free(async_pf_cache, work); |
224 | return 0; | |
225 | } | |
344d9588 GN |
226 | |
227 | int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) | |
228 | { | |
229 | struct kvm_async_pf *work; | |
230 | ||
64f638c7 | 231 | if (!list_empty_careful(&vcpu->async_pf.done)) |
344d9588 GN |
232 | return 0; |
233 | ||
234 | work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); | |
235 | if (!work) | |
236 | return -ENOMEM; | |
237 | ||
f2e10669 | 238 | work->wakeup_all = true; |
344d9588 GN |
239 | INIT_LIST_HEAD(&work->queue); /* for list_del to work */ |
240 | ||
64f638c7 | 241 | spin_lock(&vcpu->async_pf.lock); |
344d9588 | 242 | list_add_tail(&work->link, &vcpu->async_pf.done); |
64f638c7 XG |
243 | spin_unlock(&vcpu->async_pf.lock); |
244 | ||
344d9588 GN |
245 | vcpu->async_pf.queued++; |
246 | return 0; | |
247 | } |