From: Nicolin Chen <nicolinc@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: <will@kernel.org>, <robin.murphy@arm.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>
Subject: Re: [PATCH v9 08/12] iommu/arm-smmu-v3-kdump: Reserve crashed kernel's ASIDs and VMIDs
Date: Sat, 22 Aug 2026 11:14:14 -0700 [thread overview]
Message-ID: <aonm9nwqlf7uvJ0+@nvidia.com> (raw)
In-Reply-To: <178735412602.18212.13784336777302966750.b4-review@b4>
On Fri, Aug 21, 2026 at 08:15:26PM -0300, Jason Gunthorpe wrote:
> > Nested STE's guest-owned CD table is in IPA space and left alone: its ASIDs
> > only pair with the nonzero S2VMID being reserved, so they cannot alias this
> > kernel's VMID-0 or EL2 stage-1 domains.
>
> This explanation is a bit off.. Nested ASIDs have a unique ASID space under
> their VMID. SO long as the VMID is reserved there is no reason to inspect the
> (VMID,ASID) list.
Updated:
A nested STE's guest-owned CD table is left alone, since its ASIDs live in
a space of their own under that STE's VMID. Reserving that VMID covers all
of them, so there is no reason for the scan to walk the (VMID, ASID) pairs
behind it. The only ASIDs needing a reservation are those in the space that
this kernel uses for its own domains.
Thanks
Nicolin
next prev parent reply other threads:[~2026-08-22 18:14 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-21 19:48 [PATCH v9 00/12] iommu/arm-smmu-v3: Adopt the crashed kernel's stream table for kdump Nicolin Chen
2026-07-21 19:48 ` [PATCH v9 01/12] iommu/arm-smmu-v3: Do not enable EVTQ/PRIQ interrupts in kdump kernel Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-08-22 18:12 ` Nicolin Chen
2026-07-21 19:48 ` [PATCH v9 02/12] iommu/arm-smmu-v3: Skip EVTQ/PRIQ setup " Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-08-22 18:22 ` Nicolin Chen
2026-07-21 19:48 ` [PATCH v9 03/12] iommu/arm-smmu-v3: Add strtab parse helpers to a new arm-smmu-v3-kexec.c Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-07-21 19:48 ` [PATCH v9 04/12] iommu/arm-smmu-v3: Destroy vmid_map ida via devres Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-07-21 19:48 ` [PATCH v9 05/12] iommu/arm-smmu-v3: Add ARM_SMMU_OPT_KDUMP_ADOPT for kdump kernel Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-07-21 19:48 ` [PATCH v9 06/12] iommu/arm-smmu-v3-kexec: Add a CD table parse helper Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-07-21 19:48 ` [PATCH v9 07/12] iommu/arm-smmu-v3-kexec: Add ASID/VMID reservation helpers Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-08-22 2:07 ` Nicolin Chen
2026-08-22 18:51 ` Nicolin Chen
2026-08-22 19:59 ` Jason Gunthorpe
2026-08-22 20:21 ` Nicolin Chen
2026-07-21 19:48 ` [PATCH v9 08/12] iommu/arm-smmu-v3-kdump: Reserve crashed kernel's ASIDs and VMIDs Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-08-22 18:14 ` Nicolin Chen [this message]
2026-07-21 19:48 ` [PATCH v9 09/12] iommu/arm-smmu-v3-kdump: Implement is_attach_deferred() Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-08-22 18:16 ` Nicolin Chen
2026-08-22 20:02 ` Jason Gunthorpe
2026-08-22 20:26 ` Nicolin Chen
2026-08-25 20:08 ` Konstantin Ryabitsev
2026-07-21 21:38 ` [PATCH v9 10/12] iommu/arm-smmu-v3: Retain CR0_SMMUEN during kdump device reset Nicolin Chen
2026-07-21 21:38 ` [PATCH v9 11/12] iommu/arm-smmu-v3: Skip RMR bypass for kdump adoption Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
2026-07-21 21:38 ` [PATCH v9 12/12] iommu/arm-smmu-v3: Detect ARM_SMMU_OPT_KDUMP_ADOPT in probe() Nicolin Chen
2026-08-21 23:15 ` Jason Gunthorpe
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