From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id A33F76B02CD for ; Tue, 24 Aug 2010 05:25:49 -0400 (EDT) Message-ID: <4C73900D.1080404@redhat.com> Date: Tue, 24 Aug 2010 12:25:33 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [PATCH v5 09/12] Retry fault before vmentry References: <1279553462-7036-1-git-send-email-gleb@redhat.com> <1279553462-7036-10-git-send-email-gleb@redhat.com> In-Reply-To: <1279553462-7036-10-git-send-email-gleb@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Gleb Natapov Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mingo@elte.hu, a.p.zijlstra@chello.nl, tglx@linutronix.de, hpa@zytor.com, riel@redhat.com, cl@linux-foundation.org, mtosatti@redhat.com List-ID: On 07/19/2010 06:30 PM, Gleb Natapov wrote: > When page is swapped in it is mapped into guest memory only after guest > tries to access it again and generate another fault. To save this fault > we can map it immediately since we know that guest is going to access > the page. > > > > -static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, > - u32 error_code) > +static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code, > + bool sync) 'sync' means something else in the shadow mmu. Please rename to something longer, maybe 'apf_completion'. Alternatively, split to two functions, a base function that doesn't do apf and a wrapper that handles apf. > @@ -505,6 +506,37 @@ out_unlock: > return 0; > } > > +static int FNAME(page_fault_other_cr3)(struct kvm_vcpu *vcpu, gpa_t cr3, > + gva_t addr, u32 error_code) > +{ > + int r = 0; > + gpa_t curr_cr3 = vcpu->arch.cr3; > + > + if (curr_cr3 != cr3) { > + /* > + * We do page fault on behalf of a process that is sleeping > + * because of async PF. PV guest takes reference to mm that cr3 > + * belongs too, so it has to be valid here. > + */ > + kvm_set_cr3(vcpu, cr3); > + if (kvm_mmu_reload(vcpu)) > + goto switch_cr3; > + } With nested virtualization, we need to switch cr0, cr4, and efer as well... > + > + r = FNAME(page_fault)(vcpu, addr, error_code, true); > + > + if (kvm_check_request(KVM_REQ_MMU_SYNC, vcpu)) > + kvm_mmu_sync_roots(vcpu); Why is this needed? > + > +switch_cr3: > + if (curr_cr3 != vcpu->arch.cr3) { > + kvm_set_cr3(vcpu, curr_cr3); > + kvm_mmu_reload(vcpu); > + } > + > + return r; > +} This has the nasty effect of flushing the TLB on AMD. > + > static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva) > { > struct kvm_shadow_walk_iterator iterator; > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 2603cc4..5482db0 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -5743,6 +5743,15 @@ void kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags) > } > EXPORT_SYMBOL_GPL(kvm_set_rflags); > > +void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, > + struct kvm_async_pf *work) > +{ > + if (!vcpu->arch.mmu.page_fault_other_cr3 || is_error_page(work->page)) > + return; > + vcpu->arch.mmu.page_fault_other_cr3(vcpu, work->arch.cr3, work->gva, > + work->arch.error_code); > +} > + > static int apf_put_user(struct kvm_vcpu *vcpu, u32 val) > { > if (unlikely(vcpu->arch.apf_memslot_ver != > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index f56e8ac..de1d5b6 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1348,6 +1348,7 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) > spin_lock(&vcpu->async_pf_lock); > list_del(&work->link); > spin_unlock(&vcpu->async_pf_lock); > + kvm_arch_async_page_ready(vcpu, work); > put_page(work->page); > async_pf_work_free(work); > list_del(&work->queue); > @@ -1366,6 +1367,7 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) > list_del(&work->queue); > vcpu->async_pf_queued--; > > + kvm_arch_async_page_ready(vcpu, work); > kvm_arch_inject_async_page_present(vcpu, work); > > put_page(work->page); -- error compiling committee.c: too many arguments to function -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org