4f70d12e392d3dcf6064c11e58ad7c8f798419ad
2 * kvm asynchronous fault support
4 * Copyright 2010 Red Hat, Inc.
7 * Gleb Natapov <gleb@redhat.com>
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.
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.
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.
23 #include <linux/kvm_host.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/mmu_context.h>
29 #include <trace/events/kvm.h>
31 static inline void kvm_async_page_present_sync(struct kvm_vcpu
*vcpu
,
32 struct kvm_async_pf
*work
)
34 #ifdef CONFIG_KVM_ASYNC_PF_SYNC
35 kvm_arch_async_page_present(vcpu
, work
);
38 static inline void kvm_async_page_present_async(struct kvm_vcpu
*vcpu
,
39 struct kvm_async_pf
*work
)
41 #ifndef CONFIG_KVM_ASYNC_PF_SYNC
42 kvm_arch_async_page_present(vcpu
, work
);
46 static struct kmem_cache
*async_pf_cache
;
48 int kvm_async_pf_init(void)
50 async_pf_cache
= KMEM_CACHE(kvm_async_pf
, 0);
58 void kvm_async_pf_deinit(void)
61 kmem_cache_destroy(async_pf_cache
);
62 async_pf_cache
= NULL
;
65 void kvm_async_pf_vcpu_init(struct kvm_vcpu
*vcpu
)
67 INIT_LIST_HEAD(&vcpu
->async_pf
.done
);
68 INIT_LIST_HEAD(&vcpu
->async_pf
.queue
);
69 spin_lock_init(&vcpu
->async_pf
.lock
);
72 static void async_pf_execute(struct work_struct
*work
)
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
;
83 get_user_pages_unlocked(NULL
, mm
, addr
, 1, 1, 0, NULL
);
84 kvm_async_page_present_sync(vcpu
, apf
);
86 spin_lock(&vcpu
->async_pf
.lock
);
87 list_add_tail(&apf
->link
, &vcpu
->async_pf
.done
);
88 spin_unlock(&vcpu
->async_pf
.lock
);
91 * apf may be freed by kvm_check_async_pf_completion() after
95 trace_kvm_async_pf_completed(addr
, gva
);
98 * This memory barrier pairs with prepare_to_wait's set_current_state()
101 if (waitqueue_active(&vcpu
->wq
))
102 wake_up_interruptible(&vcpu
->wq
);
105 kvm_put_kvm(vcpu
->kvm
);
108 void kvm_clear_async_pf_completion_queue(struct kvm_vcpu
*vcpu
)
110 /* cancel outstanding work queue item */
111 while (!list_empty(&vcpu
->async_pf
.queue
)) {
112 struct kvm_async_pf
*work
=
113 list_entry(vcpu
->async_pf
.queue
.next
,
114 typeof(*work
), queue
);
115 list_del(&work
->queue
);
117 #ifdef CONFIG_KVM_ASYNC_PF_SYNC
118 flush_work(&work
->work
);
120 if (cancel_work_sync(&work
->work
)) {
122 kvm_put_kvm(vcpu
->kvm
); /* == work->vcpu->kvm */
123 kmem_cache_free(async_pf_cache
, work
);
128 spin_lock(&vcpu
->async_pf
.lock
);
129 while (!list_empty(&vcpu
->async_pf
.done
)) {
130 struct kvm_async_pf
*work
=
131 list_entry(vcpu
->async_pf
.done
.next
,
132 typeof(*work
), link
);
133 list_del(&work
->link
);
134 kmem_cache_free(async_pf_cache
, work
);
136 spin_unlock(&vcpu
->async_pf
.lock
);
138 vcpu
->async_pf
.queued
= 0;
141 void kvm_check_async_pf_completion(struct kvm_vcpu
*vcpu
)
143 struct kvm_async_pf
*work
;
145 while (!list_empty_careful(&vcpu
->async_pf
.done
) &&
146 kvm_arch_can_inject_async_page_present(vcpu
)) {
147 spin_lock(&vcpu
->async_pf
.lock
);
148 work
= list_first_entry(&vcpu
->async_pf
.done
, typeof(*work
),
150 list_del(&work
->link
);
151 spin_unlock(&vcpu
->async_pf
.lock
);
153 kvm_arch_async_page_ready(vcpu
, work
);
154 kvm_async_page_present_async(vcpu
, work
);
156 list_del(&work
->queue
);
157 vcpu
->async_pf
.queued
--;
158 kmem_cache_free(async_pf_cache
, work
);
162 int kvm_setup_async_pf(struct kvm_vcpu
*vcpu
, gva_t gva
, unsigned long hva
,
163 struct kvm_arch_async_pf
*arch
)
165 struct kvm_async_pf
*work
;
167 if (vcpu
->async_pf
.queued
>= ASYNC_PF_PER_VCPU
)
170 /* setup delayed work */
173 * do alloc nowait since if we are going to sleep anyway we
174 * may as well sleep faulting in page
176 work
= kmem_cache_zalloc(async_pf_cache
, GFP_NOWAIT
| __GFP_NOWARN
);
180 work
->wakeup_all
= false;
185 work
->mm
= current
->mm
;
186 atomic_inc(&work
->mm
->mm_users
);
187 kvm_get_kvm(work
->vcpu
->kvm
);
189 /* this can't really happen otherwise gfn_to_pfn_async
191 if (unlikely(kvm_is_error_hva(work
->addr
)))
194 INIT_WORK(&work
->work
, async_pf_execute
);
195 if (!schedule_work(&work
->work
))
198 list_add_tail(&work
->queue
, &vcpu
->async_pf
.queue
);
199 vcpu
->async_pf
.queued
++;
200 kvm_arch_async_page_not_present(vcpu
, work
);
203 kvm_put_kvm(work
->vcpu
->kvm
);
205 kmem_cache_free(async_pf_cache
, work
);
209 int kvm_async_pf_wakeup_all(struct kvm_vcpu
*vcpu
)
211 struct kvm_async_pf
*work
;
213 if (!list_empty_careful(&vcpu
->async_pf
.done
))
216 work
= kmem_cache_zalloc(async_pf_cache
, GFP_ATOMIC
);
220 work
->wakeup_all
= true;
221 INIT_LIST_HEAD(&work
->queue
); /* for list_del to work */
223 spin_lock(&vcpu
->async_pf
.lock
);
224 list_add_tail(&work
->link
, &vcpu
->async_pf
.done
);
225 spin_unlock(&vcpu
->async_pf
.lock
);
227 vcpu
->async_pf
.queued
++;