From: Jason Gunthorpe <jgg@nvidia.com>
To: Samiullah Khawaja <skhawaja@google.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
Baolu Lu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Dmytro Maluka <dmaluka@chromium.org>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/3] iommu/vt-d: Rework hitless PASID entry replacement
Date: Wed, 14 Jan 2026 15:07:15 -0400 [thread overview]
Message-ID: <20260114190715.GC961588@nvidia.com> (raw)
In-Reply-To: <CAAywjhREggcahuWbk-ZqRjoW4v51X-gKw1pdA9TAcp-uO_6Bfg@mail.gmail.com>
On Wed, Jan 14, 2026 at 10:51:02AM -0800, Samiullah Khawaja wrote:
> There is no immediate use case for first level, as I understand we use
> second level for all our VM use cases. But looking at the code and
> specs, the first level is used for pasid compatible domains (using
> IOMMU_HWPT_ALLOC_PASID flag) and it will not be replaceable
> hitlessly..
If the VMM allocates using the NEST_PARENT flag it will always get a
S2, and that is a reasonable thing for the VMM to do.
Jason
next prev parent reply other threads:[~2026-01-14 19:07 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-13 3:00 [PATCH 0/3] iommu/vt-d: Ensure atomicity in context and PASID entry updates Lu Baolu
2026-01-13 3:00 ` [PATCH 1/3] iommu/vt-d: Use 128-bit atomic updates for context entries Lu Baolu
2026-01-13 19:27 ` Dmytro Maluka
2026-01-14 5:14 ` Baolu Lu
2026-01-14 10:55 ` Dmytro Maluka
2026-01-15 2:26 ` Baolu Lu
2026-01-15 13:12 ` Jason Gunthorpe
2026-01-14 7:54 ` Tian, Kevin
2026-01-15 3:26 ` Baolu Lu
2026-01-15 5:59 ` Tian, Kevin
2026-01-15 13:23 ` Jason Gunthorpe
2026-01-16 5:19 ` Tian, Kevin
2026-01-16 14:33 ` Jason Gunthorpe
2026-01-13 3:00 ` [PATCH 2/3] iommu/vt-d: Clear Present bit before tearing down PASID entry Lu Baolu
2026-01-13 19:34 ` Dmytro Maluka
2026-01-14 5:38 ` Baolu Lu
2026-01-14 11:12 ` Dmytro Maluka
2026-01-15 2:45 ` Baolu Lu
2026-01-15 21:35 ` Dmytro Maluka
2026-01-16 6:06 ` Baolu Lu
2026-01-20 13:49 ` Dmytro Maluka
2026-01-14 7:32 ` Tian, Kevin
2026-01-14 8:27 ` Baolu Lu
2026-01-15 5:49 ` Tian, Kevin
2026-01-13 3:00 ` [PATCH 3/3] iommu/vt-d: Rework hitless PASID entry replacement Lu Baolu
2026-01-13 15:05 ` Jason Gunthorpe
2026-01-14 6:03 ` Baolu Lu
2026-01-13 19:27 ` Samiullah Khawaja
2026-01-13 20:56 ` Jason Gunthorpe
2026-01-14 5:45 ` Baolu Lu
2026-01-14 7:26 ` Tian, Kevin
2026-01-14 13:17 ` Jason Gunthorpe
2026-01-14 18:51 ` Samiullah Khawaja
2026-01-14 19:07 ` Jason Gunthorpe [this message]
2026-01-15 5:44 ` Tian, Kevin
2026-01-15 13:28 ` Jason Gunthorpe
2026-01-16 6:16 ` Tian, Kevin
2026-01-13 19:39 ` Dmytro Maluka
2026-01-13 20:06 ` Dmytro Maluka
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