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

From: Nicolin Chen <redacted>
Sent: Wednesday, September 11, 2024 3:12 PM

On Wed, Sep 11, 2024 at 06:19:10AM +0000, Tian, Kevin wrote:

quoted

quoted

From: Nicolin Chen <redacted>
Sent: Friday, September 6, 2024 4:15 AM

On Thu, Sep 05, 2024 at 02:43:26PM -0300, Jason Gunthorpe wrote:

quoted

On Thu, Sep 05, 2024 at 10:37:45AM -0700, Nicolin Chen wrote:

quoted

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