On Mon, Nov 17, 2014 at 10:44:30AM +0100, Cornelia Huck wrote: > On Mon, 17 Nov 2014 11:37:01 +0200 > "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > > > On Mon, Nov 17, 2014 at 05:17:17PM +0800, Jason Wang wrote: > > > Buggy host may advertised buggy host features (a usual case is that host > > > advertise a feature whose dependencies were missed). In this case, driver > > > should detect and disable the buggy features by itself. > > > > > > This patch introduces driver specific sanitize_features() method which is > > > called just before features finalizing to detect and disable buggy features > > > advertised by host. > > > > > > Virtio-net will be the first user. > > > > > > Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx> > > > Cc: Michael S. Tsirkin <mst@xxxxxxxxxx> > > > Cc: Cornelia Huck <cornelia.huck@xxxxxxxxxx> > > > Cc: Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx> > > > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> > > > > Hmm this conflicts with virtio 1.0 work: we drop > > features as bitmap there. > > But that's an implementation detail, no? We'll still need a way for the > driver to sanitize features, and I think this interface works just fine. Now that you mention it, I don't think we do. The spec is quite explicit that devices must not expose invalid combinations of features. Admittedly, BUG_ON isn't very friendly to hypervisors. But e.g. failing probe seems better than trying to work around hypervisor bugs - otherwise we'll be stuck maintaining compatibility with hypervisors forever. -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
