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X-MS-Exchange-CrossTenant-Network-Message-Id: f6743434-4732-4f3b-d918-08de54170c85 X-MS-Exchange-CrossTenant-AuthSource: DM8PR12MB5445.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Jan 2026 09:18:30.8089 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: eO+a3pZIlHEJQ7czBWvUNmHFXxQFq0QpQ0oAiwC/UbTmKtHV7NVDn/07Lr6a4hJ/IaE1cX2U46Dv7Xq1Ctpo4g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB9544 On 11/18/2025 12:54 AM, Jason Gunthorpe wrote: > On Thu, Nov 13, 2025 at 01:52:02PM -0800, Nicolin Chen wrote: >> On Wed, Nov 12, 2025 at 06:24:52PM +0000, Suravee Suthikulpanit wrote: >>> Note: This series is rebased on top of: >>> * Git repo: git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux.git >>> Branch: next >>> Commit: 91920a9d87f5 ("Merge branches 'arm/smmu/updates', 'arm/smmu/bindings', >>> 'mediatek', 'nvidia/tegra', 'amd/amd-vi' and 'core' >>> into next") >>> * [PATCH v5] iommu/amd: Add support for hw_info for iommu capability query >>> https://lore.kernel.org/linux-iommu/20250926141901.511313-1-suravee.suthikulpanit@amd.com/T/#u >> >> Nit: this patch doesn't apply cleanly on 91920a9d87f5 :-/ >> >>> drivers/iommu/amd/Makefile | 2 +- >>> drivers/iommu/amd/amd_iommu.h | 36 ++++ >>> drivers/iommu/amd/amd_iommu_types.h | 48 +++++- >>> drivers/iommu/amd/init.c | 8 + >>> drivers/iommu/amd/iommu.c | 221 +++++++++++++++--------- >>> drivers/iommu/amd/iommufd.c | 50 ++++++ >>> drivers/iommu/amd/iommufd.h | 5 + >>> drivers/iommu/amd/nested.c | 259 ++++++++++++++++++++++++++++ >>> include/uapi/linux/iommufd.h | 11 ++ >> >> So, this seems to be a preparatory series for AMD vIOMMU, yet it >> doesn't properly work since it's missing IOMMUFD_VIOMMU_TYPE_AMD >> and the invalidation component (HW_QUEUE). >> >> However, the series does declare IOMMU_HWPT_DATA_AMD_GUEST in the >> uAPI header. I am afraid that might confuse user who might think >> AMD now supports virtualization using the HWPT-based mode, like >> Intel VT-d. >> >> So, maybe we should either: >> - leave a note at IOMMU_HWPT_DATA_AMD_GUEST to declare it is >> incomplete yet, and remove later >> - keep IOMMU_HWPT_DATA_AMD_GUEST in an AMD driver header, and >> move to the uAPI header later >> >> Jason? > > Yeah, I like to see this incremental work, but Alex recently raised > that we should be a bit more careful about how userspace perceives > these partially complete things. > > I don't think tricks with head files work well, I think what you'd > want to do is leave some critical system call disabled until all the > work is finished so the VMM never has to see a half working > implementation? Yes, this is a preparatory series for nested translation w/ AMD vIOMMU support. Currently, the amd_iommu_alloc_domain_nested() has not been hooked with the struct iommufd_viommu_ops.alloc_domain_nested. This is should prevent the nested domain usage until it is fully enabled in subsequent series, which will introduce the support for IOMMUFD vIOMMU for AMD. I am working on preparing and sending out the next series. Thanks, Suravee > The patch to get the info would have been a nice choice for this purpose.. > > Jason