Mario,
On 10/1/2026 11:54 PM, Mario Limonciello (AMD) wrote:
> PerfOpt is only a feature usable by integrated GPUs and only in identity
> mode. Instead of leaving a policy knob in amdgpu, just turn it on when
> an integrated GPU is in identity.
>
> PerfOpt locks the GPU into identity mode where the DTE is ignored, so mark
> it require_direct (blocks VFIO/iommufd claims) and disable PASID (no GCR3
> table in the fast path).
>
> This drops quite a bit of compatibility glue. There was a refcounting
> system, exported symbols, and device attach/detach logic. By just setting
> it immediately it's a lot more straightforward.
I believe its good to get this merged in this cycle itself so that we can get
rid of the command line options introduced earlier.
I have looked into this patch again. How about somthing like below:
- Do not call amd_iommu_perfopt_set() in early_enable_iommu() path
Because it enables feature on all IOMMUs even though it may not have iGPUs
- amd_iommu_def_domain_type:
mark device PerfOpt-eligible
select identity
- identity attach:
Enable IOMMU perfOpt feature
- DMA / Blocked domain
Disable IOMMU perfOpt feature
- resume:
restore hardware bit
-Vasant
