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    Subject[PATCH v2 7/9] KVM: SVM: Get rid of handle_fastpath_set_msr_irqoff()
    Date
    From: Wanpeng Li <wanpengli@tencent.com>

    Analysis from Sean:

    | svm->next_rip is reset in svm_vcpu_run() only after calling
    | svm_exit_handlers_fastpath(), which will cause SVM's
    | skip_emulated_instruction() to write a stale RIP.

    Let's get rid of handle_fastpath_set_msr_irqoff() in svm_exit_handlers_fastpath()
    to have a quick fix.

    Reported-by: Paul K. <kronenpj@kronenpj.dyndns.org>
    Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
    Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
    Cc: Paul K. <kronenpj@kronenpj.dyndns.org>
    Cc: <stable@vger.kernel.org> # v5.8-rc1+
    Fixes: 404d5d7bff0d (KVM: X86: Introduce more exit_fastpath_completion enum values)
    Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
    ---
    arch/x86/kvm/svm/svm.c | 5 -----
    1 file changed, 5 deletions(-)

    diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
    index 19e622a..c61bc3b 100644
    --- a/arch/x86/kvm/svm/svm.c
    +++ b/arch/x86/kvm/svm/svm.c
    @@ -3349,11 +3349,6 @@ static void svm_cancel_injection(struct kvm_vcpu *vcpu)

    static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
    {
    - if (!is_guest_mode(vcpu) &&
    - to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
    - to_svm(vcpu)->vmcb->control.exit_info_1)
    - return handle_fastpath_set_msr_irqoff(vcpu);
    -
    return EXIT_FASTPATH_NONE;
    }

    --
    2.7.4
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