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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 | { |
59 | struct page *page = NULL; |
60 | struct kvm_async_pf *apf = |
61 | container_of(work, struct kvm_async_pf, work); |
62 | struct mm_struct *mm = apf->mm; |
63 | struct kvm_vcpu *vcpu = apf->vcpu; |
64 | unsigned long addr = apf->addr; |
65 | gva_t gva = apf->gva; |
66 | |
67 | might_sleep(); |
68 | |
69 | use_mm(mm); |
70 | down_read(&mm->mmap_sem); |
71 | get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL); |
72 | up_read(&mm->mmap_sem); |
73 | unuse_mm(mm); |
74 | |
75 | spin_lock(&vcpu->async_pf.lock); |
76 | list_add_tail(&apf->link, &vcpu->async_pf.done); |
77 | apf->page = page; |
78 | apf->done = true; |
79 | spin_unlock(&vcpu->async_pf.lock); |
80 | |
81 | /* |
82 | * apf may be freed by kvm_check_async_pf_completion() after |
83 | * this point |
84 | */ |
85 | |
86 | trace_kvm_async_pf_completed(addr, page, gva); |
87 | |
88 | if (waitqueue_active(&vcpu->wq)) |
89 | wake_up_interruptible(&vcpu->wq); |
90 | |
91 | mmdrop(mm); |
92 | kvm_put_kvm(vcpu->kvm); |
93 | } |
94 | |
95 | void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) |
96 | { |
97 | /* cancel outstanding work queue item */ |
98 | while (!list_empty(&vcpu->async_pf.queue)) { |
99 | struct kvm_async_pf *work = |
100 | list_entry(vcpu->async_pf.queue.next, |
101 | typeof(*work), queue); |
102 | cancel_work_sync(&work->work); |
103 | list_del(&work->queue); |
104 | if (!work->done) /* work was canceled */ |
105 | kmem_cache_free(async_pf_cache, work); |
106 | } |
107 | |
108 | spin_lock(&vcpu->async_pf.lock); |
109 | while (!list_empty(&vcpu->async_pf.done)) { |
110 | struct kvm_async_pf *work = |
111 | list_entry(vcpu->async_pf.done.next, |
112 | typeof(*work), link); |
113 | list_del(&work->link); |
114 | if (work->page) |
115 | put_page(work->page); |
116 | kmem_cache_free(async_pf_cache, work); |
117 | } |
118 | spin_unlock(&vcpu->async_pf.lock); |
119 | |
120 | vcpu->async_pf.queued = 0; |
121 | } |
122 | |
123 | void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) |
124 | { |
125 | struct kvm_async_pf *work; |
126 | |
127 | while (!list_empty_careful(&vcpu->async_pf.done) && |
128 | kvm_arch_can_inject_async_page_present(vcpu)) { |
129 | spin_lock(&vcpu->async_pf.lock); |
130 | work = list_first_entry(&vcpu->async_pf.done, typeof(*work), |
131 | link); |
132 | list_del(&work->link); |
133 | spin_unlock(&vcpu->async_pf.lock); |
134 | |
135 | if (work->page) |
136 | kvm_arch_async_page_ready(vcpu, work); |
137 | kvm_arch_async_page_present(vcpu, work); |
138 | |
139 | list_del(&work->queue); |
140 | vcpu->async_pf.queued--; |
141 | if (work->page) |
142 | put_page(work->page); |
143 | kmem_cache_free(async_pf_cache, work); |
144 | } |
145 | } |
146 | |
147 | int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, |
148 | struct kvm_arch_async_pf *arch) |
149 | { |
150 | struct kvm_async_pf *work; |
151 | |
152 | if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU) |
153 | return 0; |
154 | |
155 | /* setup delayed work */ |
156 | |
157 | /* |
158 | * do alloc nowait since if we are going to sleep anyway we |
159 | * may as well sleep faulting in page |
160 | */ |
161 | work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT); |
162 | if (!work) |
163 | return 0; |
164 | |
165 | work->page = NULL; |
166 | work->done = false; |
167 | work->vcpu = vcpu; |
168 | work->gva = gva; |
169 | work->addr = gfn_to_hva(vcpu->kvm, gfn); |
170 | work->arch = *arch; |
171 | work->mm = current->mm; |
172 | atomic_inc(&work->mm->mm_count); |
173 | kvm_get_kvm(work->vcpu->kvm); |
174 | |
175 | /* this can't really happen otherwise gfn_to_pfn_async |
176 | would succeed */ |
177 | if (unlikely(kvm_is_error_hva(work->addr))) |
178 | goto retry_sync; |
179 | |
180 | INIT_WORK(&work->work, async_pf_execute); |
181 | if (!schedule_work(&work->work)) |
182 | goto retry_sync; |
183 | |
184 | list_add_tail(&work->queue, &vcpu->async_pf.queue); |
185 | vcpu->async_pf.queued++; |
186 | kvm_arch_async_page_not_present(vcpu, work); |
187 | return 1; |
188 | retry_sync: |
189 | kvm_put_kvm(work->vcpu->kvm); |
190 | mmdrop(work->mm); |
191 | kmem_cache_free(async_pf_cache, work); |
192 | return 0; |
193 | } |
194 | |
195 | int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) |
196 | { |
197 | struct kvm_async_pf *work; |
198 | |
199 | if (!list_empty_careful(&vcpu->async_pf.done)) |
200 | return 0; |
201 | |
202 | work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); |
203 | if (!work) |
204 | return -ENOMEM; |
205 | |
206 | work->page = bad_page; |
207 | get_page(bad_page); |
208 | INIT_LIST_HEAD(&work->queue); /* for list_del to work */ |
209 | |
210 | spin_lock(&vcpu->async_pf.lock); |
211 | list_add_tail(&work->link, &vcpu->async_pf.done); |
212 | spin_unlock(&vcpu->async_pf.lock); |
213 | |
214 | vcpu->async_pf.queued++; |
215 | return 0; |
216 | } |
217 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
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