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;
.......................
}
>
