From: Vasant Hegde <vasant.hegde@amd.com>
To: "Mario Limonciello (AMD)" <superm1@kernel.org>,
Jason Gunthorpe <jgg@ziepe.ca>
Cc: Alex Deucher <alexander.deucher@amd.com>,
Joerg Roedel <joro@8bytes.org>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
"open list:RADEON and AMDGPU DRM DRIVERS"
<amd-gfx@lists.freedesktop.org>,
open list <linux-kernel@vger.kernel.org>,
"open list:AMD IOMMU (AMD-VI)" <iommu@lists.linux.dev>
Subject: Re: [PATCH v4] iommu/amd: Make PerfOpt compulsory
Date: Fri, 2 Oct 2026 09:14:59 +0530 [thread overview]
Message-ID: <d4634df4-ab32-46df-8b05-665998959e43@amd.com> (raw)
In-Reply-To: <20261001182410.1525285-1-superm1@kernel.org>
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.
>
> Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
> Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
> ---
> v4:
> * Disable PASID for PerfOpt devices
> * Don't allow attaching a blocked domain
This will block attaching device to guest via vfio-pci. Is that fine?
-Vasant
next prev parent reply other threads:[~2026-10-02 3:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-01 18:24 [PATCH v4] iommu/amd: Make PerfOpt compulsory Mario Limonciello (AMD)
2026-10-02 3:44 ` Vasant Hegde [this message]
2026-10-02 3:57 ` Mario Limonciello
2026-10-02 11:46 ` Jason Gunthorpe
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