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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id g25sm10636592edw.92.2021.01.18.09.57.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Jan 2021 09:57:52 -0800 (PST) Subject: Re: [PATCH] KVM: x86: get smi pending status correctly To: Jay Zhou , kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, seanjc@google.com, vkuznets@redhat.com, weidong.huang@huawei.com, wangxinxin.wang@huawei.com, zhuangshengen@huawei.com References: <20210118084720.1585-1-jianjay.zhou@huawei.com> From: Paolo Bonzini Message-ID: <4b2565ca-83da-c337-ccf3-ee31a28fd605@redhat.com> Date: Mon, 18 Jan 2021 18:57:51 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210118084720.1585-1-jianjay.zhou@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18/01/21 09:47, Jay Zhou wrote: > The injection process of smi has two steps: > > Qemu KVM > Step1: > cpu->interrupt_request &= \ > ~CPU_INTERRUPT_SMI; > kvm_vcpu_ioctl(cpu, KVM_SMI) > > call kvm_vcpu_ioctl_smi() and > kvm_make_request(KVM_REQ_SMI, vcpu); > > Step2: > kvm_vcpu_ioctl(cpu, KVM_RUN, 0) > > call process_smi() if > kvm_check_request(KVM_REQ_SMI, vcpu) is > true, mark vcpu->arch.smi_pending = true; > > The vcpu->arch.smi_pending will be set true in step2, unfortunately if > vcpu paused between step1 and step2, the kvm_run->immediate_exit will be > set and vcpu has to exit to Qemu immediately during step2 before mark > vcpu->arch.smi_pending true. > During VM migration, Qemu will get the smi pending status from KVM using > KVM_GET_VCPU_EVENTS ioctl at the downtime, then the smi pending status > will be lost. > > Signed-off-by: Jay Zhou > Signed-off-by: Shengen Zhuang > --- > arch/x86/kvm/x86.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 9a8969a..9025c76 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -105,6 +105,7 @@ > > static void update_cr8_intercept(struct kvm_vcpu *vcpu); > static void process_nmi(struct kvm_vcpu *vcpu); > +static void process_smi(struct kvm_vcpu *vcpu); > static void enter_smm(struct kvm_vcpu *vcpu); > static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags); > static void store_regs(struct kvm_vcpu *vcpu); > @@ -4230,6 +4231,9 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, > { > process_nmi(vcpu); > > + if (kvm_check_request(KVM_REQ_SMI, vcpu)) > + process_smi(vcpu); > + > /* > * In guest mode, payload delivery should be deferred, > * so that the L1 hypervisor can intercept #PF before > Queued, thanks. Paolo