Re: [Qemu-devel] [PATCH 4/4] xen: Fix PV-on-HVM

[Paolo Bonzini]

Il 15/05/2012 23:00, Michael S. Tsirkin ha scritto:
> On Tue, May 15, 2012 at 04:26:39PM +0100, Anthony PERARD wrote:
>> In the context of PV-on-HVM under Xen, the emulated nics are supposed to be
>> unplug before the guest drivers are initialized. This mean that there must be
>> unplug without the consent of the guest.
>>
>> Without this patch, the guest end up with two nics with the same MAC, the
>> emulated nic and the PV nic.
>>
>> Signed-off-by: Anthony PERARD <address@hidden>
> 
> OK, so on Xen there are special devices that can be safely removed
> without telling the guest?  Does there need to be regular hotplug for
> these devices too? Or can it be always surprise removal?

On Xen the PV drivers can ask the firmware to surprise-remove the
emulated NICs.  Of course it has to do it early enough so that the guest
doesn't crash.

Paolo