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    SubjectRe: [PATCH v8 7/7] arm64: kvm: handle SError Interrupt by categorization
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    Hi James,

    On 2017/12/7 14:37, gengdongjiu wrote:
    >> We need to tackle (1) and (3) separately. For (3) we need some API that lets
    >> Qemu _trigger_ an SError in the guest, with a specified ESR. But, we don't have
    >> a way of migrating pending SError yet... which is where I got stuck last time I
    >> was looking at this.
    > I understand you most idea.
    >
    > But In the Qemu one signal type can only correspond to one behavior, can not correspond to two behaviors,
    > otherwise Qemu will do not know how to do.
    >
    > For the Qemu, if it receives the SIGBUS_MCEERR_AR signal, it will populate the CPER
    > records and inject a SEA to guest through KVM IOCTL "KVM_SET_ONE_REG"; if receives the SIGBUS_MCEERR_AO
    > signal, it will record the CPER and trigger a IRQ to notify guest, as shown below:
    >
    > SIGBUS_MCEERR_AR trigger Synchronous External Abort.
    > SIGBUS_MCEERR_AO trigger GPIO IRQ.
    >
    > For the SIGBUS_MCEERR_AO and SIGBUS_MCEERR_AR, we have already specify trigger method, which all
    >
    > not involve _trigger_ an SError.
    >
    > so there is no chance for Qemu to trigger the SError when gets the SIGBUS_MCEERR_A{O,R}.

    As I explained above:

    If Qemu received SIGBUS_MCEERR_AR, it will record CPER and trigger Synchronous External Abort;
    If Qemu received SIGBUS_MCEERR_AO, it will record CPER and trigger GPIO IRQ;
    So Qemu does not know when to _trigger_ an SError.

    so here I "return a error" to Qemu if ghes_notify_sei() return failure in [1], if you opposed KVM "return error",
    do you have a better idea about it? thanks

    About the way of migrating pending SError, I think it is a separate case, because Qemu still does not know
    how and when to trigger the SError.

    [1]:
    static int kvm_handle_guest_sei(struct kvm_vcpu *vcpu, struct kvm_run *run)
    {
    .......................
    + case ESR_ELx_AET_UER: /* The error has not been propagated */
    + /*
    + * Userspace only handle the guest SError Interrupt(SEI) if the
    + * error has not been propagated
    + */
    + run->exit_reason = KVM_EXIT_EXCEPTION;
    + run->ex.exception = ESR_ELx_EC_SERROR;
    + run->ex.error_code = KVM_SEI_SEV_RECOVERABLE;
    + return 0;
    .......................
    }

    >

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