On Wed, 11 Jan 2012 07:30:34 -0600, Anthony Liguori [off-list ref] wrote:

I think the more important thing to do is require accesses to integers in the 
config space to always be aligned and to use the appropriate accessor. 
Non-integer fields should be restricted to byte access.

That limits config space entries to 32-bit but also means that there is no need 
for a generation counter.

Unfortunately not, see virtio_blk.  capacity is 64 bits, and geometry is
multiple fields.

If we're already making the change, the endianness ought to be a feature bit.

I'd rather tie it to the new PCI config layout (and ring format).  Then
we can simply have two backends, legacy and modern.

For non-PCI, we would need a feature bit.

Cheers,
Rusty.