On Wed, Mar 21, 2012 at 02:04:34PM -0500, Anthony Liguori wrote: > On 03/13/2012 05:47 AM, Avi Kivity wrote: > >On 03/13/2012 11:18 AM, Daniel P. Berrange wrote: > >>On Mon, Mar 12, 2012 at 12:33:33PM +0200, Avi Kivity wrote: > >>>On 03/12/2012 11:04 AM, Wen Congyang wrote: > >>>>Do you have any other comments about this patch? > >>>> > >>> > >>>Not really, but I'm not 100% convinced the patch is worthwhile. It's > >>>likely to only be used by Linux, which has kexec facilities, and you can > >>>put talk to management via virtio-serial and describe the crash in more > >>>details than a simple hypercall. > >> > >>As mentioned before, I don't think virtio-serial is a good fit for this. > >>We want something that is simple& guaranteed always available. Using > >>virtio-serial requires significant setup work on both the host and guest. > > > >So what? It needs to be done anyway for the guest agent. > > > >>Many management application won't know to make a vioserial device available > >>to all guests they create. > > > >Then they won't know to deal with the panic event either. > > > >>Most administrators won't even configure kexec, > >>let alone virtio serial on top of it. > > > >It should be done by the OS vendor, not the individual admin. > > > >>The hypercall requires zero host > >>side config, and zero guest side config, which IMHO is what we need for > >>this feature. > > > >If it was this one feature, yes. But we keep getting more and more > >features like that and we bloat the hypervisor. There's a reason we > >have a host-to-guest channel, we should use it. > > The problem is that virtio-serial sucks for something like this. > How do we know if we haven't tried :) > We have two options I think: > > 1) We could reserve a portion of the hypercall space to be deferred > to userspace for stuff like this. > > 2) We could invent a new hypercall like facility that was less > bloated than virtio-serial for stuff like this using MMIO/PIO. > > Regards, > > Anthony Liguori > > > -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
