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![Xiao Guangrong](/assets/img/avatar_default.png)
After commit a2766325cf
, the error page is replaced by the
error code, it need not be released anymore
[ The patch has been compiling tested for powerpc ]
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
215 lines
5.2 KiB
C
215 lines
5.2 KiB
C
/*
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* kvm asynchronous fault support
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*
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* Copyright 2010 Red Hat, Inc.
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*
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* Author:
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* Gleb Natapov <gleb@redhat.com>
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*
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* This file is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include <linux/kvm_host.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/mmu_context.h>
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#include "async_pf.h"
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#include <trace/events/kvm.h>
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static struct kmem_cache *async_pf_cache;
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int kvm_async_pf_init(void)
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{
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async_pf_cache = KMEM_CACHE(kvm_async_pf, 0);
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if (!async_pf_cache)
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return -ENOMEM;
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return 0;
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}
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void kvm_async_pf_deinit(void)
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{
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if (async_pf_cache)
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kmem_cache_destroy(async_pf_cache);
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async_pf_cache = NULL;
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}
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void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
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{
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INIT_LIST_HEAD(&vcpu->async_pf.done);
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INIT_LIST_HEAD(&vcpu->async_pf.queue);
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spin_lock_init(&vcpu->async_pf.lock);
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}
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static void async_pf_execute(struct work_struct *work)
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{
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struct page *page = NULL;
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struct kvm_async_pf *apf =
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container_of(work, struct kvm_async_pf, work);
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struct mm_struct *mm = apf->mm;
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struct kvm_vcpu *vcpu = apf->vcpu;
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unsigned long addr = apf->addr;
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gva_t gva = apf->gva;
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might_sleep();
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use_mm(mm);
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down_read(&mm->mmap_sem);
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get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL);
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up_read(&mm->mmap_sem);
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unuse_mm(mm);
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spin_lock(&vcpu->async_pf.lock);
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list_add_tail(&apf->link, &vcpu->async_pf.done);
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apf->page = page;
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apf->done = true;
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spin_unlock(&vcpu->async_pf.lock);
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/*
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* apf may be freed by kvm_check_async_pf_completion() after
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* this point
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*/
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trace_kvm_async_pf_completed(addr, page, gva);
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if (waitqueue_active(&vcpu->wq))
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wake_up_interruptible(&vcpu->wq);
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mmdrop(mm);
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kvm_put_kvm(vcpu->kvm);
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}
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void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
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{
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/* cancel outstanding work queue item */
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while (!list_empty(&vcpu->async_pf.queue)) {
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struct kvm_async_pf *work =
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list_entry(vcpu->async_pf.queue.next,
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typeof(*work), queue);
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cancel_work_sync(&work->work);
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list_del(&work->queue);
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if (!work->done) /* work was canceled */
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kmem_cache_free(async_pf_cache, work);
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}
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spin_lock(&vcpu->async_pf.lock);
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while (!list_empty(&vcpu->async_pf.done)) {
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struct kvm_async_pf *work =
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list_entry(vcpu->async_pf.done.next,
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typeof(*work), link);
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list_del(&work->link);
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if (!is_error_page(work->page))
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kvm_release_page_clean(work->page);
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kmem_cache_free(async_pf_cache, work);
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}
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spin_unlock(&vcpu->async_pf.lock);
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vcpu->async_pf.queued = 0;
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}
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void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
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{
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struct kvm_async_pf *work;
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while (!list_empty_careful(&vcpu->async_pf.done) &&
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kvm_arch_can_inject_async_page_present(vcpu)) {
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spin_lock(&vcpu->async_pf.lock);
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work = list_first_entry(&vcpu->async_pf.done, typeof(*work),
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link);
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list_del(&work->link);
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spin_unlock(&vcpu->async_pf.lock);
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if (work->page)
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kvm_arch_async_page_ready(vcpu, work);
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kvm_arch_async_page_present(vcpu, work);
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list_del(&work->queue);
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vcpu->async_pf.queued--;
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if (!is_error_page(work->page))
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kvm_release_page_clean(work->page);
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kmem_cache_free(async_pf_cache, work);
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}
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}
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int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
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struct kvm_arch_async_pf *arch)
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{
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struct kvm_async_pf *work;
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if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
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return 0;
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/* setup delayed work */
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/*
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* do alloc nowait since if we are going to sleep anyway we
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* may as well sleep faulting in page
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*/
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work = kmem_cache_zalloc(async_pf_cache, GFP_NOWAIT);
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if (!work)
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return 0;
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work->page = NULL;
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work->done = false;
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work->vcpu = vcpu;
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work->gva = gva;
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work->addr = gfn_to_hva(vcpu->kvm, gfn);
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work->arch = *arch;
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work->mm = current->mm;
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atomic_inc(&work->mm->mm_count);
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kvm_get_kvm(work->vcpu->kvm);
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/* this can't really happen otherwise gfn_to_pfn_async
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would succeed */
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if (unlikely(kvm_is_error_hva(work->addr)))
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goto retry_sync;
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INIT_WORK(&work->work, async_pf_execute);
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if (!schedule_work(&work->work))
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goto retry_sync;
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list_add_tail(&work->queue, &vcpu->async_pf.queue);
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vcpu->async_pf.queued++;
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kvm_arch_async_page_not_present(vcpu, work);
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return 1;
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retry_sync:
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kvm_put_kvm(work->vcpu->kvm);
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mmdrop(work->mm);
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kmem_cache_free(async_pf_cache, work);
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return 0;
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}
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int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
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{
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struct kvm_async_pf *work;
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if (!list_empty_careful(&vcpu->async_pf.done))
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return 0;
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work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
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if (!work)
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return -ENOMEM;
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work->page = KVM_ERR_PTR_BAD_PAGE;
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INIT_LIST_HEAD(&work->queue); /* for list_del to work */
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spin_lock(&vcpu->async_pf.lock);
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list_add_tail(&work->link, &vcpu->async_pf.done);
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spin_unlock(&vcpu->async_pf.lock);
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vcpu->async_pf.queued++;
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return 0;
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}
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