Re: [Qemu-devel] [SeaBIOS] [PATCH 02/18] virtio: run drivers in 32bit mode

[Gerd Hoffmann]

On Fr, 2015-07-03 at 08:45 +0200, Paolo Bonzini wrote:
> 
> On 29/06/2015 10:53, Gerd Hoffmann wrote:
> > virtio version 1.0 registers can (and actually do in the qemu
> > implementation) live in mmio space.  So we must run the blk and
> > scsi virtio drivers in 32bit mode, otherwise we can't access them.
> > 
> > This also allows to drop a bunch of GET_LOWFLAT calls from the virtio
> > code in the following patches.
> 
> This isn't really necessary though.  The config access capability exists
> for this reason.  At least as a follow up it would be nice to add a switch.

Just saw mst's patch implementing it in qemu.  I'll have a look. 

I think I want keep the virtio drivers as 32bit drivers.  The modern
virtio bar is a 64bit though, so accessing via config access capability
might be needed even for the 32bit drivers in case it is mapped above
4G ...

cheers,
  Gerd