KVM: x86: get smi pending status correctly

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>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 79fa55de635cc9968de380ab71fb13bbce18d570..d7ed1fd36ebac162adcc42e96098385ecde13b96 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -98,6 +98,7 @@ static u64 __read_mostly efer_reserved_bits = ~((u64)EFER_SCE);
 
 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);
 
@@ -3290,6 +3291,10 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu,
                                               struct kvm_vcpu_events *events)
 {
        process_nmi(vcpu);
+
+       if (kvm_check_request(KVM_REQ_SMI, vcpu))
+               process_smi(vcpu);
+
        /*
         * FIXME: pass injected and pending separately.  This is only
         * needed for nested virtualization, whose state cannot be