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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 | ||
31 | static struct kmem_cache *async_pf_cache; | |
32 | ||
33 | int kvm_async_pf_init(void) | |
34 | { | |
35 | async_pf_cache = KMEM_CACHE(kvm_async_pf, 0); | |
36 | ||
37 | if (!async_pf_cache) | |
38 | return -ENOMEM; | |
39 | ||
40 | return 0; | |
41 | } | |
42 | ||
43 | void kvm_async_pf_deinit(void) | |
44 | { | |
45 | if (async_pf_cache) | |
46 | kmem_cache_destroy(async_pf_cache); | |
47 | async_pf_cache = NULL; | |
48 | } | |
49 | ||
50 | void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu) | |
51 | { | |
52 | INIT_LIST_HEAD(&vcpu->async_pf.done); | |
53 | INIT_LIST_HEAD(&vcpu->async_pf.queue); | |
54 | spin_lock_init(&vcpu->async_pf.lock); | |
55 | } | |
56 | ||
57 | static void async_pf_execute(struct work_struct *work) | |
58 | { | |
af585b92 GN |
59 | struct kvm_async_pf *apf = |
60 | container_of(work, struct kvm_async_pf, work); | |
61 | struct mm_struct *mm = apf->mm; | |
62 | struct kvm_vcpu *vcpu = apf->vcpu; | |
63 | unsigned long addr = apf->addr; | |
64 | gva_t gva = apf->gva; | |
65 | ||
66 | might_sleep(); | |
67 | ||
68 | use_mm(mm); | |
69 | down_read(&mm->mmap_sem); | |
f2e10669 | 70 | get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL); |
af585b92 GN |
71 | up_read(&mm->mmap_sem); |
72 | unuse_mm(mm); | |
73 | ||
74 | spin_lock(&vcpu->async_pf.lock); | |
75 | list_add_tail(&apf->link, &vcpu->async_pf.done); | |
af585b92 GN |
76 | spin_unlock(&vcpu->async_pf.lock); |
77 | ||
78 | /* | |
79 | * apf may be freed by kvm_check_async_pf_completion() after | |
80 | * this point | |
81 | */ | |
82 | ||
f2e10669 | 83 | trace_kvm_async_pf_completed(addr, gva); |
af585b92 GN |
84 | |
85 | if (waitqueue_active(&vcpu->wq)) | |
86 | wake_up_interruptible(&vcpu->wq); | |
87 | ||
88 | mmdrop(mm); | |
89 | kvm_put_kvm(vcpu->kvm); | |
90 | } | |
91 | ||
92 | void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) | |
93 | { | |
94 | /* cancel outstanding work queue item */ | |
95 | while (!list_empty(&vcpu->async_pf.queue)) { | |
96 | struct kvm_async_pf *work = | |
97 | list_entry(vcpu->async_pf.queue.next, | |
98 | typeof(*work), queue); | |
af585b92 | 99 | list_del(&work->queue); |
98fda169 | 100 | if (cancel_work_sync(&work->work)) { |
28b441e2 RK |
101 | mmdrop(work->mm); |
102 | kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */ | |
af585b92 | 103 | kmem_cache_free(async_pf_cache, work); |
28b441e2 | 104 | } |
af585b92 GN |
105 | } |
106 | ||
107 | spin_lock(&vcpu->async_pf.lock); | |
108 | while (!list_empty(&vcpu->async_pf.done)) { | |
109 | struct kvm_async_pf *work = | |
110 | list_entry(vcpu->async_pf.done.next, | |
111 | typeof(*work), link); | |
112 | list_del(&work->link); | |
af585b92 GN |
113 | kmem_cache_free(async_pf_cache, work); |
114 | } | |
115 | spin_unlock(&vcpu->async_pf.lock); | |
116 | ||
117 | vcpu->async_pf.queued = 0; | |
118 | } | |
119 | ||
120 | void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) | |
121 | { | |
122 | struct kvm_async_pf *work; | |
123 | ||
15096ffc XG |
124 | while (!list_empty_careful(&vcpu->async_pf.done) && |
125 | kvm_arch_can_inject_async_page_present(vcpu)) { | |
126 | spin_lock(&vcpu->async_pf.lock); | |
127 | work = list_first_entry(&vcpu->async_pf.done, typeof(*work), | |
128 | link); | |
129 | list_del(&work->link); | |
130 | spin_unlock(&vcpu->async_pf.lock); | |
af585b92 | 131 | |
f2e10669 | 132 | kvm_arch_async_page_ready(vcpu, work); |
15096ffc | 133 | kvm_arch_async_page_present(vcpu, work); |
af585b92 | 134 | |
15096ffc XG |
135 | list_del(&work->queue); |
136 | vcpu->async_pf.queued--; | |
15096ffc XG |
137 | kmem_cache_free(async_pf_cache, work); |
138 | } | |
af585b92 GN |
139 | } |
140 | ||
141 | int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, | |
142 | struct kvm_arch_async_pf *arch) | |
143 | { | |
144 | struct kvm_async_pf *work; | |
145 | ||
146 | if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU) | |
147 | return 0; | |
148 | ||
149 | /* setup delayed work */ | |
150 | ||
151 | /* | |
152 | * do alloc nowait since if we are going to sleep anyway we | |
153 | * may as well sleep faulting in page | |
154 | */ | |
155 | work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT); | |
156 | if (!work) | |
157 | return 0; | |
158 | ||
f2e10669 | 159 | work->wakeup_all = false; |
af585b92 GN |
160 | work->vcpu = vcpu; |
161 | work->gva = gva; | |
162 | work->addr = gfn_to_hva(vcpu->kvm, gfn); | |
163 | work->arch = *arch; | |
164 | work->mm = current->mm; | |
165 | atomic_inc(&work->mm->mm_count); | |
166 | kvm_get_kvm(work->vcpu->kvm); | |
167 | ||
168 | /* this can't really happen otherwise gfn_to_pfn_async | |
169 | would succeed */ | |
170 | if (unlikely(kvm_is_error_hva(work->addr))) | |
171 | goto retry_sync; | |
172 | ||
173 | INIT_WORK(&work->work, async_pf_execute); | |
174 | if (!schedule_work(&work->work)) | |
175 | goto retry_sync; | |
176 | ||
177 | list_add_tail(&work->queue, &vcpu->async_pf.queue); | |
178 | vcpu->async_pf.queued++; | |
179 | kvm_arch_async_page_not_present(vcpu, work); | |
180 | return 1; | |
181 | retry_sync: | |
182 | kvm_put_kvm(work->vcpu->kvm); | |
183 | mmdrop(work->mm); | |
184 | kmem_cache_free(async_pf_cache, work); | |
185 | return 0; | |
186 | } | |
344d9588 GN |
187 | |
188 | int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) | |
189 | { | |
190 | struct kvm_async_pf *work; | |
191 | ||
64f638c7 | 192 | if (!list_empty_careful(&vcpu->async_pf.done)) |
344d9588 GN |
193 | return 0; |
194 | ||
195 | work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); | |
196 | if (!work) | |
197 | return -ENOMEM; | |
198 | ||
f2e10669 | 199 | work->wakeup_all = true; |
344d9588 GN |
200 | INIT_LIST_HEAD(&work->queue); /* for list_del to work */ |
201 | ||
64f638c7 | 202 | spin_lock(&vcpu->async_pf.lock); |
344d9588 | 203 | list_add_tail(&work->link, &vcpu->async_pf.done); |
64f638c7 XG |
204 | spin_unlock(&vcpu->async_pf.lock); |
205 | ||
344d9588 GN |
206 | vcpu->async_pf.queued++; |
207 | return 0; | |
208 | } |