Re: [RFC 0/2] virtio: provide a way for host to monitor critical events in the device

[Gleb Natapov <gleb@redhat.com>]

On Tue, Jul 24, 2012 at 02:31:25PM +0200, Sasha Levin wrote:
> On 07/24/2012 02:28 PM, Gleb Natapov wrote:
> > On Tue, Jul 24, 2012 at 02:26:33PM +0200, Sasha Levin wrote:
> >> On 07/24/2012 09:44 AM, Gleb Natapov wrote:
> >>> On Mon, Jul 23, 2012 at 10:32:39PM +0200, Sasha Levin wrote:
> >>>> As it was discussed recently, there's currently no way for the guest to notify
> >>>> the host about panics. Further more, there's no reasonable way to notify the
> >>>> host of other critical events such as an OOM kill.
> >>>>
> >>>> This short patch series introduces a new device named virtio-notifier which
> >>>> does two simple things:
> >>>>
> >>>>  1. Provide a simple interface for the guest to notify the host of critical
> >>> To get early OOPSes virtio will have to be compiled into the kernel. If
> >>> your are so keen on using virtio for this though, why not just use
> >>> dedicated virtio serial channel?
> >>
> >> Let's separate between having log for these events and receiving notifications about them.
> >>
> >> For the log part, I can already run a simple serial console to dump everything somewhere. I'm more concerned about having notifications about something critical happening when the guest is already up and running.
> >>
> > I am talking about notifications. Run your notification protocol over
> > dedicated virtio-serial channel. Logs goes to virtio-console as you've
> > said.
> 
> Ah, so just add another channel into virtio-serial to pass these notifications? Good idea - I'll look into it.
> 
Yes, that's what I mean. This solution still has the disadvantage of not
been able to catch early boot oopses without compiling the whole virtio
into a kernel image.

--
			Gleb.