On Wed, Nov 26, 2014 at 10:09:54AM +0100, Cornelia Huck wrote: > On Tue, 25 Nov 2014 23:20:11 +0200 > "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > > > On Tue, Nov 25, 2014 at 06:29:42PM +0100, Cornelia Huck wrote: > > > On Tue, 25 Nov 2014 18:41:35 +0200 > > > "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > > > > > > > disable virtio 1.0 in transports that don't > > > > support it yet. > > > > > > I'd prefer if you disabled it for _every_ transport in this patch, > > > until the needed infrastructure is in place. Else this is a bit > > > confusing. > > > > Well the only transports left are pci and rpoc, and these only > > read the low 32 bit of the features from the device - > > so there's nothing to clear. > > > > E.g. the following would be even more confusing, would it not: > > > > u32 features; > > .... > > features &= ~BIT_ULL(VIRTIO_F_VERSION_1); > > > > Agree? > > Maybe you should tweak the patch description a bit and mention that you > only disable virtio 1.0 for transports where it is actually needed? > > (...) Yes, I did that now. > > > FWIW, as negotiating a revision >= 1 is a pre-req for virtio 1.0 > > > support on ccw, virtio 1.0 is already implicitly disabled. > > > > Ah, you mean device guarantees that VIRTIO_F_VERSION_1 isn't set > > if guest sets revision to 0? > > Yes, the bit will not be offered if the revision is 0 or has not been > set at all. > > > In that case it's probably best to drop this from both ccw > > devices. > > There's only one ccw transport :) > > The old s390 virtio transport in kvm_virtio.c is not part of virtio 1.0. It might or might not be a good idea to add code in kvm_virtio.c blacklisting VIRTIO_F_VERSION_1, just in case there's a buggy device that sets it. As correct devices won't set it, I don't think we need to worry about it too much. We can make it a patch on top later if we want. -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
