From: Christoph Hellwig <hch@infradead.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Mario Limonciello <mario.limonciello@amd.com>,
Alex Deucher <alexander.deucher@amd.com>,
Joerg Roedel <joro@8bytes.org>,
amd-gfx@lists.freedesktop.org,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Vasant Hegde <vasant.hegde@amd.com>,
Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
"open list:AMD IOMMU (AMD-VI)" <iommu@lists.linux.dev>,
Jatin Kataria <jkataria@netflix.com>,
Boqun Feng <boqunf@netflix.com>,
"Derek J . Clark" <derekjohn.clark@gmail.com>
Subject: Re: [PATCH v2 1/2] iommu/amd: Add PerfOpt IOMMU performance optimization support
Date: Sun, 27 Sep 2026 22:17:04 -0700 [thread overview]
Message-ID: <arn4UPLhYJeNNxnZ@infradead.org> (raw)
In-Reply-To: <20260924225018.GB16465@ziepe.ca>
On Thu, Sep 24, 2026 at 07:50:18PM -0300, Jason Gunthorpe wrote:
> On Mon, Sep 07, 2026 at 11:12:06PM -0500, Mario Limonciello wrote:
> > +EXPORT_SYMBOL_GPL(amd_iommu_enable_perfopt);
>
> Last time we hardwired the GPU and IOMMU drivers together it was a
> huge mess to undo.
Every time a driver depends on an exact iommu driver is a major design
problem.
> Why does the GPU driver have to request this? Why can't the iommu
> driver know that this is a special device that can use this magic fast
> path and then auto set it when identity is asked for?
>
> How does the GPU driver even know it is magic special?
Yes. And WTF is "perfopt" supposed to mean. Everything is a
performance optimization.
next prev parent reply other threads:[~2026-09-28 8:43 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-08 4:12 [PATCH v2 0/2] IOMMU Performance Optimization support Mario Limonciello
2026-09-08 4:12 ` [PATCH v2 1/2] iommu/amd: Add PerfOpt IOMMU performance optimization support Mario Limonciello
2026-09-24 22:50 ` Jason Gunthorpe
2026-09-25 0:03 ` Mario Limonciello
2026-09-25 0:17 ` Jason Gunthorpe
2026-09-25 0:21 ` Mario Limonciello
2026-09-25 7:20 ` Joerg Roedel
2026-09-25 12:28 ` Jason Gunthorpe
2026-09-25 13:11 ` Mario Limonciello
2026-09-25 22:39 ` Jason Gunthorpe
2026-09-26 0:33 ` Mario Limonciello
2026-09-28 12:08 ` Jason Gunthorpe
2026-09-28 15:32 ` Mario Limonciello
2026-09-28 17:11 ` Jason Gunthorpe
2026-09-28 17:15 ` Mario Limonciello
2026-09-29 2:53 ` Deucher, Alexander
2026-09-28 5:17 ` Christoph Hellwig [this message]
2026-09-25 7:30 ` Joerg Roedel
2026-09-08 4:12 ` [PATCH v2 2/2] drm/amdgpu: Enable PerfOpt IOMMU perf optimization when GPU in identity domain Mario Limonciello
2026-09-20 14:10 ` [PATCH v2 0/2] IOMMU Performance Optimization support Mario Limonciello
2026-09-20 16:27 ` Boqun Feng
2026-09-24 11:42 ` Joerg Roedel
2026-09-24 13:01 ` Deucher, Alexander
2026-09-24 13:50 ` Joerg Roedel
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