Re: [Qemu-devel] [PATCH 1/1] kvm: log available guest crash parameters

From: "Denis V. Lunev" <den@openvz.org>
To: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org
Cc: Anton Nefedov <anton.nefedov@virtuozzo.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Richard Henderson <rth@twiddle.net>,
	Eduardo Habkost <ehabkost@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 1/1] kvm: log available guest crash parameters
Date: Tue, 31 Jan 2017 18:46:38 +0300	[thread overview]
Message-ID: <d26e3800-e0bb-2c89-f704-bc7ce1ec9393@openvz.org> (raw)
In-Reply-To: <5f9269e3-0cff-0916-cecf-f21a68337c0f@redhat.com>

On 01/31/2017 06:43 PM, Paolo Bonzini wrote:
>
> On 31/01/2017 05:07, Denis V. Lunev wrote:
>> From: Anton Nefedov <anton.nefedov@virtuozzo.com>
>>
>> Windows reports BSOD parameters through Hyper-V crash MSRs. This
>> information is very useful for initial crash analysis and thus
>> it would be nice to see it in the QEMU log file. There is suitable
>> log mask for the purpose.
>>
>> Linux guest does not provide this information, but still it would
>> be nice to log that we have crashed.
> We tell libvirt that the guest crashed through a QMP event, so I think
> this should be passed as arguments of the QMP event.  You could add:
>
> - a QAPI type GuestPanicInformation
>
> {'union': 'GuestPanicInformation',
>  'data': { 'hyper-v': 'GuestPanicInformationHyperV' } }
>
> {'struct': 'GuestPanicInformationHyperV',
>  'data': { 'arg1': 'uint64',
>            'arg2': 'uint64',
>            'arg3': 'uint64',
>            'arg4': 'uint64' } }
>
> - a QOM property on the CPU object, crash-information, whose getter
> returns an error unless cpu->crash_occurred = true
>
> - an optional GuestPanicInformation argument to the GUEST_PANICKED
> event, which is passed if the QOM property returns a non-error value
I like the idea of the event but also want to have the log message.
LOG_GUEST_ERROR level fits well to the idea at my opinion.

Thank you for the idea :)

Den