[libvirt] ARM KVM GICv3 Support

[Andrea Bolognani]

On Tue, 2015-12-15 at 11:11 +0100, Christoffer Dall wrote:
> On Tue, Dec 15, 2015 at 10:36:32AM +0100, Martin Kletzander wrote:
> > On Mon, Dec 14, 2015 at 10:47:26AM -0600, Andrew Jones wrote:
> > > On Mon, Dec 14, 2015 at 12:31:59PM +0100, Christoffer Dall wrote:
> > > > Hi all,
> > > > 
> > > > I'm trying to figure out what the correct solution for libvirt support
> > > > for ARM KVM guests with GICv3 is.
> > > > 
> > > > The challenge is that QEMU's virt machine model defaults to GICv2 unless
> > > > you specify an additional "-machine gic-version=host" parameter to QEMU,
> > > > in which case your VM gets the same GIC version as your host.
> > > > 
> > > > Now, I'm told that this is inconvenient for libvirt, because it
> > > > typically does not pass any -machine options, is that correct?
> > 
> > We do pass some options, for example, you can restrict the GIC to v2:
> > https://libvirt.org/formatdomain.html#elementsFeatures
> > 
> > That could be modified to work for your purpose IIUC, right?
> > 
> How do I figure out which values the version can take (v2, v3, host?)
> and which QEMU cmdline that translates into?

The parser will currently accept any numeric value, including eg. 1
and 42. The value 2 is special and is silently ignored for backwards
compatibility; any other value will cause libvirt to add the
gic-version option to the machine type.

Cheers.

-- 
Andrea Bolognani
Software Engineer - Virtualization Team