Re: [PATCH] uio_pci_generic does not export memory resources

Michael S. Tsirkin
2012-06-10T14:17:45Z

On Fri, Jun 08, 2012 at 11:11:16AM -0600, Alex Williamson wrote:
> On Fri, 2012-06-08 at 18:44 +0200, Hans J. Koch wrote:
> > On Fri, Jun 08, 2012 at 06:16:18PM +0200, Andreas Hartmann wrote:
> > > Hi Dominic,
> > >
> > > Dominic Eschweiler wrote:
> > > > Am Freitag, den 08.06.2012, 08:16 -0600 schrieb Alex Williamson:
> > > >> Yes, thanks Jan. This is exactly what VFIO does. VFIO provides
> > > >> secure config space access, resource access, DMA mapping services, and
> > > >> full interrupt support to userspace.
> >
> > VFIO is not a "better UIO". It *requires* an IOMMU. Dominic didn't say on
> > what CPU he's working, so it's not clear if he can use VFIO at all.
> >
> > UIO is intended for general use with devices that have mappable registers
> > and don't fit into any other subsystem. No more, no less.
>
> VFIO is a secure UIO.

A secure UIO *for VFs*. I think that's why it's called VFIO :).
Other stuff sometimes also works but no real guarantees, though
VFIO tries to make sure you don't burn yourself too badly
if it breaks.

--
MST