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

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:

quoted

we only have virtual device ID in its data structure. Also, the
virtual device sounds a bit confusing, given we already have idev.

idev is "iommufd device" which is the physical device

The virtual device is the host side handle of a device in a VM.

Yea, we need that narrative in kdoc to clearly separate them.

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.

Nicolin