Re: [PATCH RFCv1 2/3] PCI: Allow ATS to be always on for non-CXL NVIDIA GPUs

Jason Gunthorpe
2026-01-19T18:00:31Z

On Fri, Jan 16, 2026 at 08:56:41PM -0800, Nicolin Chen wrote:
> Some non-CXL NVIDIA GPU devices support non-PASID ATS function when their
> RIDs are IOMMU bypassed. This is slightly different than the default ATS
> policy which would only enable ATS on demand: when a non-zero PASID line
> is enabled in SVA use cases.

Not support, require non-PASID ATS.

I've been describing these devices as pre-CXL, in that they have many
CXL like properties, including what motivated the prior patch, but do
not implement the CXL config space.

> +/* Some non-CXL devices support ATS on RID when it is IOMMU-bypassed */

Require not support

This also looks OK to me

Jason