RE: [PATCH v2 06/19] iommufd/viommu: Add IOMMU_VIOMMU_SET/UNSET_VDEV_ID ioctl

[Tian, Kevin]

> From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Sent: Wednesday, September 11, 2024 3:12 PM
> 
> On Wed, Sep 11, 2024 at 06:19:10AM +0000, Tian, Kevin wrote:
> > > From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> > > Sent: Friday, September 6, 2024 4:15 AM
> > >
> > > On Thu, Sep 05, 2024 at 02:43:26PM -0300, Jason Gunthorpe wrote:
> > > > On Thu, Sep 05, 2024 at 10:37:45AM -0700, Nicolin Chen wrote:
> > > > > That being said, if we have a clear picture that in the long term
> > > > > we would extend it to hold more information, I think it could be
> > > > > a smart move.
> > > > >
> > > > > Perhaps virtual device can have its own "attach" to vIOMMU? Or
> > > > > would you still prefer attaching via proxy hwpt_nested?
> > > >
> > > > I was thinking just creating it against a vIOMMU is an effective
> > > > "attach" and the virtual device is permanently tied to the vIOMMU at
> > > > creation time.
> > >
> > > Ah, right! The create is per-viommu, so it's being attached.
> > >
> >
> > presumably we also need check compatibility between the idev
> > which the virtual device is created against and the stage-2 pgtable,
> > as a normal attach required?
> 
> If that's required, it can be a part of "create virtual device",
> where idev and viommu (holding s2 hwpt) would be all available?
> 

yes