From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753476AbaIPLfH (ORCPT ); Tue, 16 Sep 2014 07:35:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:2721 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751229AbaIPLfE (ORCPT ); Tue, 16 Sep 2014 07:35:04 -0400 Message-ID: <54182056.6020705@redhat.com> Date: Tue, 16 Sep 2014 13:34:46 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Tang Chen , gleb@kernel.org, mtosatti@redhat.com, nadav.amit@gmail.com, jan.kiszka@web.de CC: kvm@vger.kernel.org, laijs@cn.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, guz.fnst@cn.fujitsu.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 5/6] kvm, mem-hotplug: Reload L1's apic access page on migration when L2 is running. References: <1410864122-12434-1-git-send-email-tangchen@cn.fujitsu.com> <1410864122-12434-6-git-send-email-tangchen@cn.fujitsu.com> In-Reply-To: <1410864122-12434-6-git-send-email-tangchen@cn.fujitsu.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 16/09/2014 12:42, Tang Chen ha scritto: > This patch only handle "L1 and L2 vm share one apic access page" situation. > > When L1 vm is running, if the shared apic access page is migrated, mmu_notifier will > request all vcpus to exit to L0, and reload apic access page physical address for > all the vcpus' vmcs (which is done by patch 5/6). And when it enters L2 vm, L2's vmcs > will be updated in prepare_vmcs02() called by nested_vm_run(). So we need to do > nothing. > > When L2 vm is running, if the shared apic access page is migrated, mmu_notifier will > request all vcpus to exit to L0, and reload apic access page physical address for > all L2 vmcs. And this patch requests apic access page reload in L2->L1 vmexit. > > Signed-off-by: Tang Chen But if kvm_vcpu_reload_apic_access_page is called when the active VMCS is a VMCS02, the APIC access address will be corrupted, no? So, even if you are not touching the pages pinned by nested virt, you need an if (!is_guest_mode(vcpu) || !(vmx->nested.current_vmcs12->secondary_vm_exec_control & SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) as suggested by Gleb in the review of v5. Paolo > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/vmx.c | 6 ++++++ > arch/x86/kvm/x86.c | 3 ++- > 3 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 514183e..92b3e72 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1046,6 +1046,7 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu); > int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu); > int kvm_cpu_get_interrupt(struct kvm_vcpu *v); > void kvm_vcpu_reset(struct kvm_vcpu *vcpu); > +void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu); > > void kvm_define_shared_msr(unsigned index, u32 msr); > void kvm_set_shared_msr(unsigned index, u64 val, u64 mask); > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index a1a9797..d0d5981 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -8795,6 +8795,12 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, > } > > /* > + * We are now running in L2, mmu_notifier will force to reload the > + * page's hpa for L2 vmcs. Need to reload it for L1 before entering L1. > + */ > + kvm_vcpu_reload_apic_access_page(vcpu); > + > + /* > * Exiting from L2 to L1, we're now back to L1 which thinks it just > * finished a VMLAUNCH or VMRESUME instruction, so we need to set the > * success or failure flag accordingly. > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 27c3d30..3f458b2 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -5989,7 +5989,7 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu) > kvm_apic_update_tmr(vcpu, tmr); > } > > -static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu) > +void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu) > { > /* > * apic access page could be migrated. When the page is being migrated, > @@ -6001,6 +6001,7 @@ static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu) > kvm_x86_ops->set_apic_access_page_addr(vcpu->kvm, > page_to_phys(vcpu->kvm->arch.apic_access_page)); > } > +EXPORT_SYMBOL_GPL(kvm_vcpu_reload_apic_access_page); > > /* > * Returns 1 to let __vcpu_run() continue the guest execution loop without >