--- /dev/null
+/*
+ * kvm asynchronous fault support
+ *
+ * Copyright 2010 Red Hat, Inc.
+ *
+ * Author:
+ * Gleb Natapov <gleb@redhat.com>
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <linux/kvm_host.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/mmu_context.h>
+
+#include "async_pf.h"
+#include <trace/events/kvm.h>
+
+static inline void kvm_async_page_present_sync(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work)
+{
+#ifdef CONFIG_KVM_ASYNC_PF_SYNC
+ kvm_arch_async_page_present(vcpu, work);
+#endif
+}
+static inline void kvm_async_page_present_async(struct kvm_vcpu *vcpu,
+ struct kvm_async_pf *work)
+{
+#ifndef CONFIG_KVM_ASYNC_PF_SYNC
+ kvm_arch_async_page_present(vcpu, work);
+#endif
+}
+
+static struct kmem_cache *async_pf_cache;
+
+int kvm_async_pf_init(void)
+{
+ async_pf_cache = KMEM_CACHE(kvm_async_pf, 0);
+
+ if (!async_pf_cache)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void kvm_async_pf_deinit(void)
+{
+ if (async_pf_cache)
+ kmem_cache_destroy(async_pf_cache);
+ async_pf_cache = NULL;
+}
+
+void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
+{
+ INIT_LIST_HEAD(&vcpu->async_pf.done);
+ INIT_LIST_HEAD(&vcpu->async_pf.queue);
+ spin_lock_init(&vcpu->async_pf.lock);
+}
+
+static void async_pf_execute(struct work_struct *work)
+{
+ struct kvm_async_pf *apf =
+ container_of(work, struct kvm_async_pf, work);
+ struct mm_struct *mm = apf->mm;
+ struct kvm_vcpu *vcpu = apf->vcpu;
+ unsigned long addr = apf->addr;
+ gva_t gva = apf->gva;
+
+ might_sleep();
+
+ get_user_pages_unlocked(NULL, mm, addr, 1, 1, 0, NULL);
+ kvm_async_page_present_sync(vcpu, apf);
+
+ spin_lock(&vcpu->async_pf.lock);
+ list_add_tail(&apf->link, &vcpu->async_pf.done);
+ spin_unlock(&vcpu->async_pf.lock);
+
+ /*
+ * apf may be freed by kvm_check_async_pf_completion() after
+ * this point
+ */
+
+ trace_kvm_async_pf_completed(addr, gva);
+
+ if (swaitqueue_active(&vcpu->wq))
+ swait_wake_interruptible(&vcpu->wq);
+
+ mmput(mm);
+ kvm_put_kvm(vcpu->kvm);
+}
+
+void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
+{
+ /* cancel outstanding work queue item */
+ while (!list_empty(&vcpu->async_pf.queue)) {
+ struct kvm_async_pf *work =
+ list_entry(vcpu->async_pf.queue.next,
+ typeof(*work), queue);
+ list_del(&work->queue);
+
+#ifdef CONFIG_KVM_ASYNC_PF_SYNC
+ flush_work(&work->work);
+#else
+ if (cancel_work_sync(&work->work)) {
+ mmput(work->mm);
+ kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */
+ kmem_cache_free(async_pf_cache, work);
+ }
+#endif
+ }
+
+ spin_lock(&vcpu->async_pf.lock);
+ while (!list_empty(&vcpu->async_pf.done)) {
+ struct kvm_async_pf *work =
+ list_entry(vcpu->async_pf.done.next,
+ typeof(*work), link);
+ list_del(&work->link);
+ kmem_cache_free(async_pf_cache, work);
+ }
+ spin_unlock(&vcpu->async_pf.lock);
+
+ vcpu->async_pf.queued = 0;
+}
+
+void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
+{
+ struct kvm_async_pf *work;
+
+ while (!list_empty_careful(&vcpu->async_pf.done) &&
+ kvm_arch_can_inject_async_page_present(vcpu)) {
+ spin_lock(&vcpu->async_pf.lock);
+ work = list_first_entry(&vcpu->async_pf.done, typeof(*work),
+ link);
+ list_del(&work->link);
+ spin_unlock(&vcpu->async_pf.lock);
+
+ kvm_arch_async_page_ready(vcpu, work);
+ kvm_async_page_present_async(vcpu, work);
+
+ list_del(&work->queue);
+ vcpu->async_pf.queued--;
+ kmem_cache_free(async_pf_cache, work);
+ }
+}
+
+int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva,
+ struct kvm_arch_async_pf *arch)
+{
+ struct kvm_async_pf *work;
+
+ if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
+ return 0;
+
+ /* setup delayed work */
+
+ /*
+ * do alloc nowait since if we are going to sleep anyway we
+ * may as well sleep faulting in page
+ */
+ work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT);
+ if (!work)
+ return 0;
+
+ work->wakeup_all = false;
+ work->vcpu = vcpu;
+ work->gva = gva;
+ work->addr = hva;
+ work->arch = *arch;
+ work->mm = current->mm;
+ atomic_inc(&work->mm->mm_users);
+ kvm_get_kvm(work->vcpu->kvm);
+
+ /* this can't really happen otherwise gfn_to_pfn_async
+ would succeed */
+ if (unlikely(kvm_is_error_hva(work->addr)))
+ goto retry_sync;
+
+ INIT_WORK(&work->work, async_pf_execute);
+ if (!schedule_work(&work->work))
+ goto retry_sync;
+
+ list_add_tail(&work->queue, &vcpu->async_pf.queue);
+ vcpu->async_pf.queued++;
+ kvm_arch_async_page_not_present(vcpu, work);
+ return 1;
+retry_sync:
+ kvm_put_kvm(work->vcpu->kvm);
+ mmput(work->mm);
+ kmem_cache_free(async_pf_cache, work);
+ return 0;
+}
+
+int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
+{
+ struct kvm_async_pf *work;
+
+ if (!list_empty_careful(&vcpu->async_pf.done))
+ return 0;
+
+ work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
+ if (!work)
+ return -ENOMEM;
+
+ work->wakeup_all = true;
+ INIT_LIST_HEAD(&work->queue); /* for list_del to work */
+
+ spin_lock(&vcpu->async_pf.lock);
+ list_add_tail(&work->link, &vcpu->async_pf.done);
+ spin_unlock(&vcpu->async_pf.lock);
+
+ vcpu->async_pf.queued++;
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff