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KVM: x86: get smi pending status correctly 

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>
This commit is contained in:
Jay Zhou 2021-01-18 16:47:20 +08:00 committed by Paolo Bonzini
parent 98dd2f108e
commit 1f7becf1b7
1 changed files with 4 additions and 0 deletions
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4
arch/x86/kvm/x86.c
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@ -105,6 +105,7 @@ static u64 __read_mostly cr4_reserved_bits = CR4_RESERVED_BITS;
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