Re: [PATCH v5 2/3] virtio_pci: Use the DMA API for virtqueues when possible

Michael S. Tsirkin
2014-10-01T07:36:21Z

On Tue, Sep 30, 2014 at 05:53:37PM +0200, Paolo Bonzini wrote:
> Il 30/09/2014 17:38, Michael S. Tsirkin ha scritto:
> > I think that is true but it seems that this will be true for x86 for
> > QEMU 2.2 unless we make some changes there.
> > Which we might not have the time for since 2.2 is feature frozen
> > from tomorrow.
> > Maybe we should disable the IOMMU in 2.2, this is worth considering.
>
> It is disabled by default, no? And only supported by Q35 which does not
> yet have migration compatibility (though we are versioning it, not sure
> why that is the case).
>
> Paolo

I'm not sure what it has to do with migration.
It's disabled by default of course but if it's known not to
work correctly with virtio we are better off disabling
virtio when iommu is enabled or hiding the feature
from users altogether until we figure it out.

--
MST