Re: [Qemu-devel] [PATCH v2 for-2.5] virtio-pci: Set the QEMU_PCI_CAP_EXPRESS capability early in its DeviceClass realize method

[Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>]

Hi Michael,

On Wed, 2 Dec 2015 18:49:24 +0200 "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Wed, Dec 02, 2015 at 05:11:28PM +0200, Marcel Apfelbaum wrote:
> > The only thing I want to mention here, (see earlier discussion: https://www.mail-archive.com/qemu-devel@nongnu.org/msg338963.html)
> > is that in some cases the PCI config space will have PCIe length, even if the device is not express.
> > 
> > To be more precise, the only interesting scenario is when we plug a virtio device directly into
> > the root complex, in this case we'll have a PCI device with a PCIe config space.
> > 
> > However this happens for other devices as well, it looks like a common practice.
> 
> Problem is, if this happens migration breaks as we
> changed config space size from 2.4.

Correct me if wrong, but as long as a pre 2.5 hardware is used, Marcel's
x-disable-pcie gets on (see HW_COMPAT_2_4), thus the device will not be
a "pci_is_express", and it will have a small config space size. Isn't it
so?

Regards,
Shmulik