Re: [Qemu-devel] [PATCH RFC] virtio-pci: add MMIO property

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

On Tue, Mar 20, 2012 at 10:22:42AM +1030, Rusty Russell wrote:
> On Mon, 19 Mar 2012 17:13:06 -0500, Anthony Liguori <anthony@codemonkey.ws> wrote:
> > > Maybe just make this a hidden option like x-miio?
> > 
> > x-violate-the-virtio-spec-to-trick-old-linux-drivers-into-working-on-power?
> 
> "To configure the device, we use the first I/O region of the PCI
> device."
> 
> Meh, it does sound a little like we are specifying that it's an PCI I/O
> bar.
> 
> Let's resurrect the PCI-v2 idea, which is ready to implement now, and a
> nice cleanup?  Detach it from the change-of-ring-format idea which is
> turning out to be a tarpit.
> 
> Thanks,
> Rusty.

Yes. But it seems silly to even write code to play with device config in
memory when we agreed the right thing to do is to use a config vq
everywhere.

Now a question: does a oconfig vq look like a PCI specific
feature to you, a work-around for lack of multibyte atomic
accesses? If yes it's sane to make it a PCI capability.
Or is it something most transports would need? If yes we
need a feature bit and this is a chicken and egg problem ...

> -- 
>   How could I marry someone with more hair than me?  http://baldalex.org