From: Jay Zhou jianjay.zhou@huawei.com
commit 1f7becf1b7e21794fc9d460765fe09679bc9b9e0 upstream.
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 jianjay.zhou@huawei.com Signed-off-by: Shengen Zhuang zhuangshengen@huawei.com Message-Id: 20210118084720.1585-1-jianjay.zhou@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/x86.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -97,6 +97,7 @@ static u64 __read_mostly efer_reserved_b
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);
@@ -3199,6 +3200,10 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_ struct kvm_vcpu_events *events) { process_nmi(vcpu); + + if (kvm_check_request(KVM_REQ_SMI, vcpu)) + process_smi(vcpu); + events->exception.injected = vcpu->arch.exception.pending && !kvm_exception_is_soft(vcpu->arch.exception.nr);