[libvirt] [PATCH 2/2] HACK: qemu: aarch64: Use virtio-pci if user specifies PCI controller

[Andrea Bolognani]

On Thu, 2016-03-10 at 09:56 +0000, Daniel P. Berrange wrote:
> So, I've just seen that QEMU has decided that as of QEMU 2.6, the virt
> machine type will start to be versioned.  This is quite convenient I
> think as it gives us a nice thing to hook on. ie we see a non-versioned
> machine type of 'virt' then we use virtio-mmio addressing, however, if
> we see a versioned virt-X.Y.Z machine type, then we can assume pci by
> default.
> 
> Since the long term plan for AArch64 is to use PCI for everything, this
> gives us nice default behaviour from this point onwards, while not
> breaking compatibility for existing early adopters.
> 
> Of course people with "legacy" mmio-only guests will stll have a little
> pain to run then on new QEMU, but honestly I think that's worth it since
> it will avoid us long term pain in the world where aarch64 uses pci for
> everything

I think it's way too early to flip the switch and default to
PCI addresses: my understanding is that guest OS support is
expected to be spotty at best for at least a couple more
years.

Cheers.

-- 
Andrea Bolognani
Software Engineer - Virtualization Team