Re: [virtio] [PATCH] pci: missing documentation for dealing with 64 bit config fields

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Thu, 2 Apr 2015 12:06:41 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Thu, Apr 02, 2015 at 11:01:45AM +0200, Cornelia Huck wrote:
> > On Wed, 1 Apr 2015 20:42:13 +0200
> > "Michael S. Tsirkin" <mst@redhat.com> wrote:

> > > +For device configuration access, the driver MUST use 8-bit wide
> > > +accesses for 8-bit wide fields, 16-bit wide and aligned accesses
> > > +for 16-bit wide fields and 32-bit wide and aligned accesses for
> > > +32-bit and 64-bit wide fields. For 64-bit fields, the driver MAY
> > > +access each of the high and low 32-bit parts of the field
> > > +independently.
> > 
> > Doesn't the last sentence follow from "use 32-bit wide accesses"
> > already?
> 
> Someone might assume that driver must always access low part,
> then high part. Last sentence says it does not have to.
> 

OK, that clears it up then.