From: Jason Gunthorpe <jgg@ziepe.ca>
To: Joonwon Kang <joonwonkang@google.com>
Cc: robin.murphy@arm.com, Alexander.Grest@microsoft.com,
amhetre@nvidia.com, baolu.lu@linux.intel.com,
easwar.hariharan@linux.microsoft.com, iommu@lists.linux.dev,
jacob.jun.pan@linux.intel.com, joro@8bytes.org, jpb@kernel.org,
kees@kernel.org, kevin.tian@intel.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, nicolinc@nvidia.com,
praan@google.com, smostafa@google.com, will@kernel.org
Subject: Re: [PATCH RFC] iommu: Enable per-device SSID space for SVA
Date: Tue, 12 May 2026 12:11:33 -0300 [thread overview]
Message-ID: <20260512151133.GD7702@ziepe.ca> (raw)
In-Reply-To: <20260512145138.3414002-1-joonwonkang@google.com>
On Tue, May 12, 2026 at 02:51:38PM +0000, Joonwon Kang wrote:
> Appreciate all your clarifications here. So, my understanding is that if
> our system does not support ST64BV and ST64BV0 or if our device does not
> distinguish between the posted write and the non-posted write regarding
> PASID, then we can lift the use of the global PASID space. Can I say this?
You should do what Robin said - just have your driver use a per-device
PASID that it allocates and never use the global pasid allocator.
To do this lightly re-organize the SVA code so the driver can supply
its own PASID, and in this mode we wouldn't activate the ENQCMD
features in the mm.
Jason
next prev parent reply other threads:[~2026-05-12 15:11 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260424085339.3503582-1-joonwonkang@google.com>
[not found] ` <20260424133953.GY3611611@ziepe.ca>
2026-05-07 8:15 ` [PATCH RFC] iommu: Enable per-device SSID space for SVA Tian, Kevin
2026-05-09 17:03 ` Jason Gunthorpe
2026-05-07 9:58 ` Joonwon Kang
2026-05-09 17:10 ` Jason Gunthorpe
2026-05-11 12:39 ` Robin Murphy
2026-05-11 13:21 ` Jason Gunthorpe
2026-05-12 9:57 ` Joonwon Kang
2026-05-12 12:40 ` Jason Gunthorpe
2026-05-12 13:53 ` Robin Murphy
2026-05-12 14:51 ` Joonwon Kang
2026-05-12 15:11 ` Jason Gunthorpe [this message]
2026-05-12 10:07 ` Joonwon Kang
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