From: Will Deacon <will@kernel.org>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: robin.murphy@arm.com, jgg@nvidia.com, joro@8bytes.org,
praan@google.com, kevin.tian@intel.com, smostafa@google.com,
linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, jamien@nvidia.com, kas@kernel.org
Subject: Re: [PATCH v10 02/13] iommu/arm-smmu-v3: Make the ASID space per SMMU instance
Date: Sun, 4 Oct 2026 14:23:55 +0100 [thread overview]
Message-ID: <asJTaw0lU9cRN4Gk@willie-the-truck> (raw)
In-Reply-To: <782e24224c916ad0f48de1a49c139e71c8db0ef2.1788130528.git.nicolinc@nvidia.com>
On Sun, Aug 30, 2026 at 04:18:03PM -0700, Nicolin Chen wrote:
> An ASID tags the TLB entries within one SMMU, so two instances can use the
> same ASID without ever aliasing each other. Yet the driver allocates them
> out of a single global xarray, which makes the instances share a space that
> the hardware keeps apart, and lets one instance exhaust the IDs of another.
>
> That global space is a leftover from the BTM support that shared ASIDs with
> the CPU. Now ARM_SMMU_FEAT_BTM is never set, nothing looks a domain up by
> its ASID, and a domain is pinned to one SMMU at the attach.
We probably need to figure out what we're doing with BTM. Over at:
https://lore.kernel.org/r/20260907184513.GA2543240@ziepe.ca
Jason was talking about bringing it back once the remaining invs stuff
has landed. If that happens, what is the correct sequence to allocate
the same ASID on every SMMU instance after these patches?
Will
next prev parent reply other threads:[~2026-10-04 13:24 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-30 23:18 [PATCH v10 00/13] iommu/arm-smmu-v3: Adopt the crashed kernel's stream table for kdump Nicolin Chen
2026-08-30 23:18 ` [PATCH v10 01/13] iommu/arm-smmu-v3: Init the vmid_map ida before the stream table setup Nicolin Chen
2026-08-30 23:18 ` [PATCH v10 02/13] iommu/arm-smmu-v3: Make the ASID space per SMMU instance Nicolin Chen
2026-09-23 16:39 ` Jason Gunthorpe
2026-10-04 13:23 ` Will Deacon [this message]
2026-10-04 16:22 ` Jason Gunthorpe
2026-08-30 23:18 ` [PATCH v10 03/13] iommu/arm-smmu-v3: Add ARM_SMMU_FEAT_EVTQ for the event queue Nicolin Chen
2026-09-02 11:21 ` Kiryl Shutsemau
2026-09-23 16:39 ` Jason Gunthorpe
2026-10-04 13:24 ` Will Deacon
2026-10-04 20:20 ` Nicolin Chen
2026-10-05 4:37 ` Nicolin Chen
2026-08-30 23:18 ` [PATCH v10 04/13] iommu/arm-smmu-v3: Disable the EVTQ and the PRIQ in a kdump kernel Nicolin Chen
2026-09-02 11:22 ` Kiryl Shutsemau
2026-09-23 16:39 ` Jason Gunthorpe
2026-08-30 23:18 ` [PATCH v10 05/13] iommu/arm-smmu-v3: Add strtab parse helpers to a new arm-smmu-v3-kexec.c Nicolin Chen
2026-08-30 23:18 ` [PATCH v10 06/13] iommu/arm-smmu-v3: Add ARM_SMMU_OPT_KDUMP_ADOPT for kdump kernel Nicolin Chen
2026-10-04 13:25 ` Will Deacon
2026-10-04 16:35 ` Jason Gunthorpe
2026-10-04 20:59 ` Nicolin Chen
2026-10-05 6:34 ` Will Deacon
2026-10-05 8:04 ` Nicolin Chen
2026-10-04 20:47 ` Nicolin Chen
2026-10-05 6:32 ` Will Deacon
2026-10-05 7:56 ` Nicolin Chen
2026-10-05 8:10 ` Will Deacon
2026-08-30 23:18 ` [PATCH v10 07/13] iommu/arm-smmu-v3-kexec: Add a CD table parse helper Nicolin Chen
2026-08-30 23:18 ` [PATCH v10 08/13] iommu/arm-smmu-v3-kexec: Add ASID/VMID reservation helpers Nicolin Chen
2026-09-23 16:39 ` Jason Gunthorpe
2026-08-30 23:18 ` [PATCH v10 09/13] iommu/arm-smmu-v3-kdump: Reserve crashed kernel's ASIDs and VMIDs Nicolin Chen
2026-08-30 23:18 ` [PATCH v10 10/13] iommu/arm-smmu-v3-kdump: Implement is_attach_deferred() Nicolin Chen
2026-08-30 23:18 ` [PATCH v10 11/13] iommu/arm-smmu-v3: Retain CR0_SMMUEN during kdump device reset Nicolin Chen
2026-08-30 23:18 ` [PATCH v10 12/13] iommu/arm-smmu-v3: Skip RMR bypass for kdump adoption Nicolin Chen
2026-08-30 23:18 ` [PATCH v10 13/13] iommu/arm-smmu-v3: Detect ARM_SMMU_OPT_KDUMP_ADOPT in probe() Nicolin Chen
2026-09-14 10:41 ` [PATCH v10 00/13] iommu/arm-smmu-v3: Adopt the crashed kernel's stream table for kdump Breno Leitao
2026-09-28 15:23 ` Cristian Prundeanu
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