From: "Suthikulpanit, Suravee" <suravee.suthikulpanit@amd.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
joro@8bytes.org, yi.l.liu@intel.com, kevin.tian@intel.com,
nicolinc@nvidia.com, vasant.hegde@amd.com, jon.grimm@amd.com,
santosh.shukla@amd.com, sairaj.arunkodilkar@amd.com,
jay.chen@amd.com, wvw@google.com, wnliu@google.com,
dantuluris@google.com, chriscli@google.com, kpsingh@google.com
Subject: Re: [PATCH v3 19/22] iommu/amd: Add per-segment translate device ID pool
Date: Mon, 27 Jul 2026 17:38:38 +0700 [thread overview]
Message-ID: <889494cd-6bd8-4fff-b71b-59f6ee747bec@amd.com> (raw)
In-Reply-To: <20260707143659.GG220801@nvidia.com>
On 7/7/2026 9:36 PM, Jason Gunthorpe wrote:
> On Mon, Jun 29, 2026 at 03:35:32PM +0000, Suravee Suthikulpanit wrote:
>> Track translate-device-id slots per PCI segment so real PCI device IDs can
>> be reserved for normal DTE programming and excluded from dynamic allocation
>> for vIOMMU translation DTEs.
>
> Why does it have to be per segment? The segment is encoded in the
> devid isn't it?
This is per-segment because the AMD IOMMU device table is per-segment.
> This seems like a sketchy design to me, is it impossible to atomically
> change the viommu used devids once they start being used? It seems
> like this should be doable
>
> If so the algorithm would be simpler, just maintain an xarray of all
> dev ids, if the entry is marked as a VIOMMU and PCI needs it then move
> the VIOMMU out of the way and use the entry for PCI.
>
> No need to try to guess what ranges are usable or not.
Thanks for suggestion. I'm implementing this in V4.
Suravee
next prev parent reply other threads:[~2026-07-27 10:38 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-29 15:35 [PATCH v3 00/22] iommu/amd: Introduce AMD Hardware-accelerated Virtualized IOMMU (vIOMMU) Support Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 01/22] iommu/amd: Make amd_iommu_completion_wait() non-static Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 02/22] iommu/amd: Introduce vIOMMU-specific events and event Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 03/22] iommu/amd: Detect and initialize AMD vIOMMU feature Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 04/22] iommu/amd: Introduce IOMMUFD vIOMMU support for AMD Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 05/22] iommu/amd: Allocate Guest IDs for IOMMUFD vIOMMU instances Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 06/22] iommu/amd: Map vIOMMU VF and VF Control MMIO BARs Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 07/22] iommu/amd: Add support for AMD vIOMMU VF MMIO region Suravee Suthikulpanit
2026-07-07 14:33 ` Jason Gunthorpe
2026-07-15 11:00 ` Suthikulpanit, Suravee
2026-06-29 15:35 ` [PATCH v3 08/22] iommu/amd: Introduce Reset vMMIO Command Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 09/22] iommu/amd: Introduce and map vIOMMU private IPA region Suravee Suthikulpanit
2026-07-07 14:07 ` Jason Gunthorpe
2026-07-27 13:21 ` Suthikulpanit, Suravee
2026-06-29 15:35 ` [PATCH v3 10/22] iommu/amd: Pass iommu to device_flush_dte() Suravee Suthikulpanit
2026-07-07 14:18 ` Jason Gunthorpe
2026-06-29 15:35 ` [PATCH v3 11/22] iommu/amd: Export amd_iommu_alloc_dev_data() helper Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 12/22] iommu/amd: Pass iommu and devid to amd_iommu_make_clear_dte() Suravee Suthikulpanit
2026-07-07 14:20 ` Jason Gunthorpe
2026-06-29 15:35 ` [PATCH v3 13/22] iommu/amd: Assign IOMMU Private Address domain to IOMMU Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 14/22] iommu/amd: Add per-VM private IPA alloc/map helpers Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 15/22] iommu/amd: Add helper functions to manage DevID / DomID mapping tables Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 16/22] iommu/amd: Introduce IOMMUFD vDevice support for AMD Suravee Suthikulpanit
2026-07-07 14:31 ` Jason Gunthorpe
2026-07-15 7:56 ` Suthikulpanit, Suravee
2026-06-29 15:35 ` [PATCH v3 17/22] iommu/amd: Introduce helper function for updating domain ID mapping table Suravee Suthikulpanit
2026-07-07 14:32 ` Jason Gunthorpe
2026-07-15 9:46 ` Suthikulpanit, Suravee
2026-06-29 15:35 ` [PATCH v3 18/22] iommu/amd: Introduce helper function for updating device " Suravee Suthikulpanit
2026-06-29 15:35 ` [PATCH v3 19/22] iommu/amd: Add per-segment translate device ID pool Suravee Suthikulpanit
2026-07-07 14:36 ` Jason Gunthorpe
2026-07-27 10:38 ` Suthikulpanit, Suravee [this message]
2026-06-29 15:35 ` [PATCH v3 20/22] iommu/amd: Reserve translate-device-id for PCI requestor aliases Suravee Suthikulpanit
2026-07-07 14:39 ` Jason Gunthorpe
2026-07-21 9:39 ` Suthikulpanit, Suravee
2026-06-29 15:35 ` [PATCH v3 21/22] iommu/amd: Add translation DTE and VFctrl TransDevID helpers Suravee Suthikulpanit
2026-07-07 14:43 ` Jason Gunthorpe
2026-07-21 9:40 ` Suthikulpanit, Suravee
2026-06-29 15:35 ` [PATCH v3 22/22] iommu/amd: Assign per-vIOMMU translate device ID Suravee Suthikulpanit
2026-07-07 14:45 ` [PATCH v3 00/22] iommu/amd: Introduce AMD Hardware-accelerated Virtualized IOMMU (vIOMMU) Support Jason Gunthorpe
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