On Sun, Jan 31, 2016 at 10:09:07PM +0200, Michael S. Tsirkin wrote:
> On Fri, Jan 29, 2016 at 10:34:59AM +0000, David Vrabel wrote:
> > On 29/01/16 02:31, Andy Lutomirski wrote:
> > > Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
> > > ---
> > > drivers/virtio/virtio_ring.c | 12 ++++++++++++
> > > 1 file changed, 12 insertions(+)
> > >
> > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > > index c169c6444637..305c05cc249a 100644
> > > --- a/drivers/virtio/virtio_ring.c
> > > +++ b/drivers/virtio/virtio_ring.c
> > > @@ -47,6 +47,18 @@
> > >
> > > static bool vring_use_dma_api(void)
> > > {
> > > +#if defined(CONFIG_X86) && defined(CONFIG_XEN)
> > > + /*
> > > + * In theory, it's possible to have a buggy QEMU-supposed
> > > + * emulated Q35 IOMMU and Xen enabled at the same time. On
> > > + * such a configuration, virtio has never worked and will
> > > + * not work without an even larger kludge. Instead, enable
> > > + * the DMA API if we're a Xen guest, which at least allows
> > > + * all of the sensible Xen configurations to work correctly.
> > > + */
> > > + return static_cpu_has(X86_FEATURE_XENPV);
> >
> > You want:
> >
> > if (xen_domain())
> > return true;
> >
> > Without the #if so we use the DMA API for all types of Xen guest on all
> > architectures.
> >
> > David
>
> I doubt HVM domains can have virtio devices.
>
Yes, they can.
When virtio-pci is used virtio device is just yet another pci device
emulated by QEMU.
Wei.
> --
> MST
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
