"Michael S. Tsirkin" <m...@redhat.com> writes: > Some setups don't support enabling BAR0 (IO BAR). Reasons range from CPU > limitations (e.g. on some powerpc setups) to architecture limmitations > (e.g. a setup with >15 PCI bridges, with one virtio device behind each, > on x86). > > PCI Express spec made IO optional, so future guests will disable IO for > a device in more and more configurations. > > This patch makes it possible for host to mirror the config in BAR1, such > that these setups can work properly. > > Guests with old drivers can't be fixed, they will continue to work as > well (or as bad) as they did previously. For this reason, changing > revision id appears unnecessary - it would break setups that previously > worked, partially. > > Future work on re-organizing layout won't conflict with this patch - it > can use a different BAR or put config at an offset, or update revision. > > Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Since QEMU won't support this, I think we'll have to wait for the PCI capabilities, ie. the virtio spec 1.0. Cheers, Rusty.
