Re: [Qemu-devel] [PATCH]qemu: deal with guest paniced event

[Luiz Capitulino]

On Mon, 27 Feb 2012 11:05:58 +0800
Wen Congyang <wency@xxxxxxxxxxxxxx> wrote:

> When the host knows the guest is paniced, it will set
> exit_reason to KVM_EXIT_GUEST_PANIC. So if qemu receive
> this exit_reason, we can send a event to tell management
> application that the guest is paniced.
> 
> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
> ---
>  kvm-all.c                 |    3 +++
>  linux-headers/linux/kvm.h |    1 +
>  monitor.c                 |    3 +++
>  monitor.h                 |    1 +
>  4 files changed, 8 insertions(+), 0 deletions(-)
> 
> diff --git a/kvm-all.c b/kvm-all.c
> index c4babda..ae428ab 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -1190,6 +1190,9 @@ int kvm_cpu_exec(CPUState *env)
>                      (uint64_t)run->hw.hardware_exit_reason);
>              ret = -1;
>              break;
> +        case KVM_EXIT_GUEST_PANIC:
> +            monitor_protocol_event(QEVENT_GUEST_PANICED, NULL);
> +            break;

The event alone is not enough, because the mngt app may miss it (eg. the panic
happens before the mngt app connected to qemu).

A simple way to solve this would be to also add a new RunState called
guest-panic and make the transition to it (besides sending the event).

A more general way would be to model this after -drive's werror/rerror options,
say guest-error=report|ignore|stop. When guest-error=stop, the mngt app will
get a STOP event and can check the VM runstate to know if it's guest-panic.
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