Re: [Qemu-devel] [PATCH RFC v6 10/20] s390x/virtio-ccw: add virtio set-revision call

[Cornelia Huck]

On Tue, 20 Jan 2015 11:08:24 +0000
Stefan Hajnoczi <address@hidden> wrote:

> On Thu, Dec 11, 2014 at 02:25:12PM +0100, Cornelia Huck wrote:
> > @@ -608,6 +631,25 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
> >              }
> >          }
> >          break;
> > +    case CCW_CMD_SET_VIRTIO_REV:
> > +        len = sizeof(revinfo);
> > +        if (ccw.count < len || (check_len && ccw.count > len)) {
> > +            ret = -EINVAL;
> > +            break;
> > +        }
> > +        if (!ccw.cda) {
> > +            ret = -EFAULT;
> > +            break;
> > +        }
> > +        cpu_physical_memory_read(ccw.cda, &revinfo, len);
> > +        if (dev->revision >= 0 ||
> > +            revinfo.revision > virtio_ccw_rev_max(dev)) {
> 
> In the next patch virtio_ccw_handle_set_vq() uses big-endian memory
> access functions to load a struct from guest memory.
> 
> Here you just copy the struct in without byteswaps.
> 
> Are the byteswaps missing here?  (I guess this normally runs big-endian
> guests on big-endian hosts so it's not noticable.)

Indeed, these are supposed to be big-endian. I'll double check the
other payloads.

Thanks for spotting this!