Re: [Qemu-devel] [PATCHv3] qemu: enable PV EOI for qemu 1.3

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Oct 22, 2012 at 12:06:42PM +0200, Andreas Färber wrote:
> Am 18.10.2012 17:01, schrieb Michael S. Tsirkin:
> > Enable KVM PV EOI by default. You can still disable it with
> > -kvm_pv_eoi cpu flag. To avoid breaking cross-version migration,
> > enable only for qemu 1.3 (or in the future, newer) machine type.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> 
> Thanks for updating,
> 
> Reviewed-by: Andreas Färber <afaerber@suse.de>
> 
> The commit message is not so telling whether there are any downsides
> (security implications?) to enabling this by default if supported,

I don't think there could be security downsides because all this does
is tell guest about the feature in a convenient way.
A well behaved guest doesn't use a feature unless it's listed but
that's irrelevant for security.

> so
> I'll leave it to Anthony to ack/apply this.
> 
> Regards,
> Andreas

It used to be enabled. It was turned off in
ef8621b1a3b199c348606c0a11a77d8e8bf135f1
because it affected migration format and doing that
just before the release seemed too risky.


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