From f2e106692d5189303997ad7b96de8d8123aa5613 Mon Sep 17 00:00:00 2001 From: chai wen Date: Mon, 14 Oct 2013 22:22:33 +0800 Subject: [PATCH] KVM: Drop FOLL_GET in GUP when doing async page fault Page pinning is not mandatory in kvm async page fault processing since after async page fault event is delivered to a guest it accesses page once again and does its own GUP. Drop the FOLL_GET flag in GUP in async_pf code, and do some simplifying in check/clear processing. Suggested-by: Gleb Natapov Signed-off-by: Gu zheng Signed-off-by: chai wen Signed-off-by: Gleb Natapov --- arch/x86/kvm/x86.c | 4 ++-- include/linux/kvm_host.h | 2 +- include/trace/events/kvm.h | 10 ++++------ virt/kvm/async_pf.c | 17 +++++------------ 4 files changed, 12 insertions(+), 21 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c951c71dc80b..edf2a07df3a3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7298,7 +7298,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) int r; if ((vcpu->arch.mmu.direct_map != work->arch.direct_map) || - is_error_page(work->page)) + work->wakeup_all) return; r = kvm_mmu_reload(vcpu); @@ -7408,7 +7408,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu, struct x86_exception fault; trace_kvm_async_pf_ready(work->arch.token, work->gva); - if (is_error_page(work->page)) + if (work->wakeup_all) work->arch.token = ~0; /* broadcast wakeup */ else kvm_del_async_pf_gfn(vcpu, work->arch.gfn); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index f6dccde755f6..c9d4236ab442 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -189,7 +189,7 @@ struct kvm_async_pf { gva_t gva; unsigned long addr; struct kvm_arch_async_pf arch; - struct page *page; + bool wakeup_all; }; void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu); diff --git a/include/trace/events/kvm.h b/include/trace/events/kvm.h index 7005d1109ec9..131a0bda7aec 100644 --- a/include/trace/events/kvm.h +++ b/include/trace/events/kvm.h @@ -296,23 +296,21 @@ DEFINE_EVENT(kvm_async_pf_nopresent_ready, kvm_async_pf_ready, TRACE_EVENT( kvm_async_pf_completed, - TP_PROTO(unsigned long address, struct page *page, u64 gva), - TP_ARGS(address, page, gva), + TP_PROTO(unsigned long address, u64 gva), + TP_ARGS(address, gva), TP_STRUCT__entry( __field(unsigned long, address) - __field(pfn_t, pfn) __field(u64, gva) ), TP_fast_assign( __entry->address = address; - __entry->pfn = page ? page_to_pfn(page) : 0; __entry->gva = gva; ), - TP_printk("gva %#llx address %#lx pfn %#llx", __entry->gva, - __entry->address, __entry->pfn) + TP_printk("gva %#llx address %#lx", __entry->gva, + __entry->address) ); #endif diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index b197950ac4d5..8631d9c14320 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -56,7 +56,6 @@ void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu) static void async_pf_execute(struct work_struct *work) { - struct page *page = NULL; struct kvm_async_pf *apf = container_of(work, struct kvm_async_pf, work); struct mm_struct *mm = apf->mm; @@ -68,13 +67,12 @@ static void async_pf_execute(struct work_struct *work) use_mm(mm); down_read(&mm->mmap_sem); - get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL); + get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL); up_read(&mm->mmap_sem); unuse_mm(mm); spin_lock(&vcpu->async_pf.lock); list_add_tail(&apf->link, &vcpu->async_pf.done); - apf->page = page; spin_unlock(&vcpu->async_pf.lock); /* @@ -82,7 +80,7 @@ static void async_pf_execute(struct work_struct *work) * this point */ - trace_kvm_async_pf_completed(addr, page, gva); + trace_kvm_async_pf_completed(addr, gva); if (waitqueue_active(&vcpu->wq)) wake_up_interruptible(&vcpu->wq); @@ -112,8 +110,6 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu) list_entry(vcpu->async_pf.done.next, typeof(*work), link); list_del(&work->link); - if (!is_error_page(work->page)) - kvm_release_page_clean(work->page); kmem_cache_free(async_pf_cache, work); } spin_unlock(&vcpu->async_pf.lock); @@ -133,14 +129,11 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) list_del(&work->link); spin_unlock(&vcpu->async_pf.lock); - if (work->page) - kvm_arch_async_page_ready(vcpu, work); + kvm_arch_async_page_ready(vcpu, work); kvm_arch_async_page_present(vcpu, work); list_del(&work->queue); vcpu->async_pf.queued--; - if (!is_error_page(work->page)) - kvm_release_page_clean(work->page); kmem_cache_free(async_pf_cache, work); } } @@ -163,7 +156,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, if (!work) return 0; - work->page = NULL; + work->wakeup_all = false; work->vcpu = vcpu; work->gva = gva; work->addr = gfn_to_hva(vcpu->kvm, gfn); @@ -203,7 +196,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) if (!work) return -ENOMEM; - work->page = KVM_ERR_PTR_BAD_PAGE; + work->wakeup_all = true; INIT_LIST_HEAD(&work->queue); /* for list_del to work */ spin_lock(&vcpu->async_pf.lock); -- 2.20.1