Commit | Line | Data |
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775c8a3d | 1 | // SPDX-License-Identifier: GPL-2.0-only |
af585b92 GN |
2 | /* |
3 | * kvm asynchronous fault support | |
4 | * | |
5 | * Copyright 2010 Red Hat, Inc. | |
6 | * | |
7 | * Author: | |
8 | * Gleb Natapov <gleb@redhat.com> | |
af585b92 GN |
9 | */ |
10 | ||
11 | #include <linux/kvm_host.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/mmu_context.h> | |
6e84f315 | 15 | #include <linux/sched/mm.h> |
af585b92 GN |
16 | |
17 | #include "async_pf.h" | |
18 | #include <trace/events/kvm.h> | |
19 | ||
20 | static struct kmem_cache *async_pf_cache; | |
21 | ||
22 | int kvm_async_pf_init(void) | |
23 | { | |
24 | async_pf_cache = KMEM_CACHE(kvm_async_pf, 0); | |
25 | ||
26 | if (!async_pf_cache) | |
27 | return -ENOMEM; | |
28 | ||
29 | return 0; | |
30 | } | |
31 | ||
32 | void kvm_async_pf_deinit(void) | |
33 | { | |
4f52696a | 34 | kmem_cache_destroy(async_pf_cache); |
af585b92 GN |
35 | async_pf_cache = NULL; |
36 | } | |
37 | ||
38 | void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu) | |
39 | { | |
40 | INIT_LIST_HEAD(&vcpu->async_pf.done); | |
41 | INIT_LIST_HEAD(&vcpu->async_pf.queue); | |
42 | spin_lock_init(&vcpu->async_pf.lock); | |
43 | } | |
44 | ||
45 | static void async_pf_execute(struct work_struct *work) | |
46 | { | |
af585b92 GN |
47 | struct kvm_async_pf *apf = |
48 | container_of(work, struct kvm_async_pf, work); | |
49 | struct mm_struct *mm = apf->mm; | |
50 | struct kvm_vcpu *vcpu = apf->vcpu; | |
51 | unsigned long addr = apf->addr; | |
736c291c | 52 | gpa_t cr2_or_gpa = apf->cr2_or_gpa; |
8b7457ef | 53 | int locked = 1; |
557a961a | 54 | bool first; |
af585b92 GN |
55 | |
56 | might_sleep(); | |
57 | ||
1e987790 | 58 | /* |
bdd303cb | 59 | * This work is run asynchronously to the task which owns |
1e987790 | 60 | * mm and might be done in another context, so we must |
8b7457ef | 61 | * access remotely. |
1e987790 | 62 | */ |
d8ed45c5 | 63 | mmap_read_lock(mm); |
ca5e8632 | 64 | get_user_pages_remote(mm, addr, 1, FOLL_WRITE, NULL, &locked); |
8b7457ef | 65 | if (locked) |
d8ed45c5 | 66 | mmap_read_unlock(mm); |
1e987790 | 67 | |
4425f567 PB |
68 | if (IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC)) |
69 | kvm_arch_async_page_present(vcpu, apf); | |
af585b92 GN |
70 | |
71 | spin_lock(&vcpu->async_pf.lock); | |
557a961a | 72 | first = list_empty(&vcpu->async_pf.done); |
af585b92 | 73 | list_add_tail(&apf->link, &vcpu->async_pf.done); |
22583f0d | 74 | apf->vcpu = NULL; |
af585b92 GN |
75 | spin_unlock(&vcpu->async_pf.lock); |
76 | ||
557a961a VK |
77 | if (!IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC) && first) |
78 | kvm_arch_async_page_present_queued(vcpu); | |
79 | ||
af585b92 GN |
80 | /* |
81 | * apf may be freed by kvm_check_async_pf_completion() after | |
82 | * this point | |
83 | */ | |
84 | ||
736c291c | 85 | trace_kvm_async_pf_completed(addr, cr2_or_gpa); |
af585b92 | 86 | |
d92a5d1c | 87 | __kvm_vcpu_wake_up(vcpu); |
af585b92 | 88 | |
41c22f62 | 89 | mmput(mm); |
af585b92 GN |
90 | kvm_put_kvm(vcpu->kvm); |
91 | } | |
92 | ||
93 | void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) | |
94 | { | |
22583f0d PB |
95 | spin_lock(&vcpu->async_pf.lock); |
96 | ||
af585b92 GN |
97 | /* cancel outstanding work queue item */ |
98 | while (!list_empty(&vcpu->async_pf.queue)) { | |
99 | struct kvm_async_pf *work = | |
433da860 GT |
100 | list_first_entry(&vcpu->async_pf.queue, |
101 | typeof(*work), queue); | |
af585b92 | 102 | list_del(&work->queue); |
9f2ceda4 | 103 | |
22583f0d PB |
104 | /* |
105 | * We know it's present in vcpu->async_pf.done, do | |
106 | * nothing here. | |
107 | */ | |
108 | if (!work->vcpu) | |
109 | continue; | |
110 | ||
111 | spin_unlock(&vcpu->async_pf.lock); | |
9f2ceda4 DD |
112 | #ifdef CONFIG_KVM_ASYNC_PF_SYNC |
113 | flush_work(&work->work); | |
114 | #else | |
98fda169 | 115 | if (cancel_work_sync(&work->work)) { |
41c22f62 | 116 | mmput(work->mm); |
28b441e2 | 117 | kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */ |
af585b92 | 118 | kmem_cache_free(async_pf_cache, work); |
28b441e2 | 119 | } |
9f2ceda4 | 120 | #endif |
22583f0d | 121 | spin_lock(&vcpu->async_pf.lock); |
af585b92 GN |
122 | } |
123 | ||
af585b92 GN |
124 | while (!list_empty(&vcpu->async_pf.done)) { |
125 | struct kvm_async_pf *work = | |
433da860 GT |
126 | list_first_entry(&vcpu->async_pf.done, |
127 | typeof(*work), link); | |
af585b92 | 128 | list_del(&work->link); |
af585b92 GN |
129 | kmem_cache_free(async_pf_cache, work); |
130 | } | |
131 | spin_unlock(&vcpu->async_pf.lock); | |
132 | ||
133 | vcpu->async_pf.queued = 0; | |
134 | } | |
135 | ||
136 | void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) | |
137 | { | |
138 | struct kvm_async_pf *work; | |
139 | ||
15096ffc | 140 | while (!list_empty_careful(&vcpu->async_pf.done) && |
7c0ade6c | 141 | kvm_arch_can_dequeue_async_page_present(vcpu)) { |
15096ffc XG |
142 | spin_lock(&vcpu->async_pf.lock); |
143 | work = list_first_entry(&vcpu->async_pf.done, typeof(*work), | |
144 | link); | |
145 | list_del(&work->link); | |
146 | spin_unlock(&vcpu->async_pf.lock); | |
af585b92 | 147 | |
f2e10669 | 148 | kvm_arch_async_page_ready(vcpu, work); |
4425f567 PB |
149 | if (!IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC)) |
150 | kvm_arch_async_page_present(vcpu, work); | |
af585b92 | 151 | |
15096ffc XG |
152 | list_del(&work->queue); |
153 | vcpu->async_pf.queued--; | |
15096ffc XG |
154 | kmem_cache_free(async_pf_cache, work); |
155 | } | |
af585b92 GN |
156 | } |
157 | ||
e8c22266 VK |
158 | /* |
159 | * Try to schedule a job to handle page fault asynchronously. Returns 'true' on | |
160 | * success, 'false' on failure (page fault has to be handled synchronously). | |
161 | */ | |
162 | bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, | |
163 | unsigned long hva, struct kvm_arch_async_pf *arch) | |
af585b92 GN |
164 | { |
165 | struct kvm_async_pf *work; | |
166 | ||
167 | if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU) | |
e8c22266 | 168 | return false; |
af585b92 | 169 | |
7863e346 VK |
170 | /* Arch specific code should not do async PF in this case */ |
171 | if (unlikely(kvm_is_error_hva(hva))) | |
e8c22266 | 172 | return false; |
af585b92 GN |
173 | |
174 | /* | |
175 | * do alloc nowait since if we are going to sleep anyway we | |
176 | * may as well sleep faulting in page | |
177 | */ | |
d7444794 | 178 | work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT | __GFP_NOWARN); |
af585b92 | 179 | if (!work) |
e8c22266 | 180 | return false; |
af585b92 | 181 | |
f2e10669 | 182 | work->wakeup_all = false; |
af585b92 | 183 | work->vcpu = vcpu; |
736c291c | 184 | work->cr2_or_gpa = cr2_or_gpa; |
e0ead41a | 185 | work->addr = hva; |
af585b92 GN |
186 | work->arch = *arch; |
187 | work->mm = current->mm; | |
3fce371b | 188 | mmget(work->mm); |
af585b92 GN |
189 | kvm_get_kvm(work->vcpu->kvm); |
190 | ||
af585b92 | 191 | INIT_WORK(&work->work, async_pf_execute); |
af585b92 GN |
192 | |
193 | list_add_tail(&work->queue, &vcpu->async_pf.queue); | |
194 | vcpu->async_pf.queued++; | |
2a18b7e7 | 195 | work->notpresent_injected = kvm_arch_async_page_not_present(vcpu, work); |
7863e346 VK |
196 | |
197 | schedule_work(&work->work); | |
198 | ||
e8c22266 | 199 | return true; |
af585b92 | 200 | } |
344d9588 GN |
201 | |
202 | int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) | |
203 | { | |
204 | struct kvm_async_pf *work; | |
557a961a | 205 | bool first; |
344d9588 | 206 | |
64f638c7 | 207 | if (!list_empty_careful(&vcpu->async_pf.done)) |
344d9588 GN |
208 | return 0; |
209 | ||
210 | work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); | |
211 | if (!work) | |
212 | return -ENOMEM; | |
213 | ||
f2e10669 | 214 | work->wakeup_all = true; |
344d9588 GN |
215 | INIT_LIST_HEAD(&work->queue); /* for list_del to work */ |
216 | ||
64f638c7 | 217 | spin_lock(&vcpu->async_pf.lock); |
557a961a | 218 | first = list_empty(&vcpu->async_pf.done); |
344d9588 | 219 | list_add_tail(&work->link, &vcpu->async_pf.done); |
64f638c7 XG |
220 | spin_unlock(&vcpu->async_pf.lock); |
221 | ||
557a961a VK |
222 | if (!IS_ENABLED(CONFIG_KVM_ASYNC_PF_SYNC) && first) |
223 | kvm_arch_async_page_present_queued(vcpu); | |
224 | ||
344d9588 GN |
225 | vcpu->async_pf.queued++; |
226 | return 0; | |
227 | } |