Re: [Qemu-devel] [PATCH V3] hw/virtio: Add PCIe capability to virtio devices

[Marcel Apfelbaum]

On 11/02/2015 02:05 PM, Cornelia Huck wrote:
> On Mon, 2 Nov 2015 12:01:06 +0200
> Marcel Apfelbaum <address@hidden> wrote:
>
> > On 11/02/2015 11:54 AM, Cornelia Huck wrote:
> > > On Mon, 2 Nov 2015 11:20:50 +0200
> > > Marcel Apfelbaum <address@hidden> wrote:
> > >
> > > > On 11/02/2015 11:07 AM, Cornelia Huck wrote:
> > > > > On Sun, 1 Nov 2015 11:15:24 +0200
> > > > > Marcel Apfelbaum <address@hidden> wrote:
> > > > >
> > > > > > By the way, HW_COMPAT_2_3 sets any-layout to off only for a few virtio devices,
> > > > > > not for all. Does anybody know if is in purpose or can we do the same for them 
> > > > > > too?
> > > > >
> > > > > net and scsi already defaulted any_layout to true before.
> > > > >
> > > > > Are any others missing?
> > > >
> > > > Hi,
> > > >
> > > > The whole list is:
> > > >     name "virtio-blk-pci", bus PCI, alias "virtio-blk"
> > > >     name "virtio-scsi-pci", bus PCI
> > > >     name "virtio-net-pci", bus PCI, alias "virtio-net"
> > > >     name "virtio-input-host-pci", bus PCI
> > > >     name "virtio-keyboard-pci", bus PCI
> > > >     name "virtio-mouse-pci", bus PCI
> > > >     name "virtio-serial-pci", bus PCI, alias "virtio-serial"
> > > >     name "virtio-tablet-pci", bus PCI
> > > >     name "virtio-gpu-pci", bus PCI
> > > >     name "virtio-balloon-pci", bus PCI, alias "virtio-balloon"
> > > >     name "virtio-rng-pci", bus PCI
> > > >
> > > >
> > > > HW_COMPAT_2_3 has:
> > > >      - virtio-blk-pci
> > > >      - virtio-balloon-pci
> > > >      - virtio-serial-pci
> > > >      - virtio-9p-pci
> > > >      - virtio-rng-pci
> > > >
> > > > You mentioned:
> > > >      - virtio-scsi-pci
> > > >      - virtio-net-pci
> > > >
> > > > I guess the remaining list is:
> > > >     - virtio-input-host-pci
> > > >     - virtio-keyboard-pci
> > > >     - virtio-mouse-pci
> > > >     - virtio-tablet-pci
> > > >     - virtio-gpu-pci
> > > >
> > > > I don't know if is is applicable to them, or if they have it defaulted to 
> > > > any_layout,
> > > > however the above devices are part of QEMU 2.3.
> > >
> > > Hm, unless I'm fumbling git commands here, they were all added post-2.3?
> >
> > I misspoke, I wanted to say that when I run (latest master branch):
> >    <qemu-bin>  -M pc-q35-2.3  -device help 2>&1 | grep virtio | grep pci
> > the devices are there.
>
> What's the word on compat machines and new device types, btw.? If we
> fire up a compat machine, we can still specify devices that were added
> with later machine versions, but of course we can't migrate to an old
> machine as the device types did not exist there. Do we want to give the
> user a hint here by disallowing new device types?

I started to wonder about this too, so I added to this thread the migration
maintainers that should be qualified to answer this :)

Thanks,
Marcel