The Linux Kernel Mailing List
 help / color / mirror / Atom feed
From: Jason Gunthorpe <jgg@nvidia.com>
To: Suravee Suthikulpanit <suravee.suthikulpanit@amd.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 v2 21/26] iommu/amd: Map kvmfd to shared translate device ID for vIOMMU
Date: Mon, 1 Jun 2026 10:35:52 -0300	[thread overview]
Message-ID: <20260601133552.GO3195266@nvidia.com> (raw)
In-Reply-To: <20260528051738.596013-22-suravee.suthikulpanit@amd.com>

On Thu, May 28, 2026 at 05:17:33AM +0000, Suravee Suthikulpanit wrote:
> Add per-PCI-segment kvmfd xarray amd_iommu_kvmfd_trans_entry with
> refcounted so all vIOMMUs for one VM share one translate-device-id and
> GPA->SPA DTE.

What? There should no KVM in the viommu implementation.

I can't understand why you did this.

AFAICT the HW needs some unused devid "TransDevID" for some
purpose. This is pretty sketchy, but OK..

The ID should be affiliated with every nest parent domain, or maybe
every vIOMMU.

It has nothing to do with KVM. You can't assume anything about iommufd
is constructing the viommu based on the KVM.

The only acceptable use of KVM in iommufd land is to get some CPU
specific shared information which this is not doing.

So no to any KVM stuff in this series.

In an AMD system there should be exactly one viommu per kvm per
physical instance anyhow.

Jsaon

  reply	other threads:[~2026-06-01 13:36 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-28  5:17 [PATCH v2 00/26] iommu/amd: Introduce AMD Hardware-accelerated Virtualized IOMMU (vIOMMU) Support Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 01/26] iommu/amd: Make amd_iommu_completion_wait() non-static Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 02/26] iommu/amd: Introduce vIOMMU-specific events and event Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 03/26] iommu/amd: Detect and initialize AMD vIOMMU feature Suravee Suthikulpanit
2026-06-01 12:43   ` Jason Gunthorpe
2026-06-05  8:45     ` Suthikulpanit, Suravee
2026-05-28  5:17 ` [PATCH v2 04/26] iommu/amd: Introduce IOMMUFD vIOMMU support for AMD Suravee Suthikulpanit
2026-06-01 12:44   ` Jason Gunthorpe
2026-06-05  8:55     ` Suthikulpanit, Suravee
2026-05-28  5:17 ` [PATCH v2 05/26] iommu/amd: Allocate Guest IDs for IOMMUFD vIOMMU instances Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 06/26] iommu/amd: Map vIOMMU VF and VF Control MMIO BARs Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 07/26] iommu/amd: Add support for AMD vIOMMU VF MMIO region Suravee Suthikulpanit
2026-06-01 12:51   ` Jason Gunthorpe
2026-05-28  5:17 ` [PATCH v2 08/26] iommu/amd: Introduce Reset vMMIO Command Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 09/26] iommu/amd: Introduce domain for IOMMU Private Address (IPA) region Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 10/26] iommu/amd: Assign IOMMU Private Address domain to IOMMU Suravee Suthikulpanit
2026-06-01 12:59   ` Jason Gunthorpe
2026-05-28  5:17 ` [PATCH v2 11/26] iommu/amd: Allocate and map vIOMMU private regions Suravee Suthikulpanit
2026-06-01 13:05   ` Jason Gunthorpe
2026-05-28  5:17 ` [PATCH v2 12/26] iommu/amd: Add per-VM private IPA alloc/map helpers Suravee Suthikulpanit
2026-05-30 20:44   ` Weinan Liu
2026-06-01 13:08   ` Jason Gunthorpe
2026-06-01 13:11   ` Jason Gunthorpe
2026-06-01 18:16   ` Weinan Liu
2026-05-28  5:17 ` [PATCH v2 13/26] iommu/amd: Add helper functions to manage DevID / DomID mapping tables Suravee Suthikulpanit
2026-05-30 21:26   ` Weinan Liu
2026-05-28  5:17 ` [PATCH v2 14/26] iommu/amd: Introduce IOMMUFD vDevice support for AMD Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 15/26] iommu/amd: Introduce helper function for updating domain ID mapping table Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 16/26] iommu/amd: Introduce helper function for updating device " Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 17/26] iommu/amd: Pass KVM FD from userspace when initializing vIOMMU Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 18/26] iommu/amd: Add translation DTE and VFctrl TransDevID helpers Suravee Suthikulpanit
2026-06-01 13:31   ` Jason Gunthorpe
2026-05-28  5:17 ` [PATCH v2 19/26] iommu/amd: Add per-segment translate device ID pool Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 20/26] iommu/amd: Reserve translate-device-id for PCI requestor aliases Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 21/26] iommu/amd: Map kvmfd to shared translate device ID for vIOMMU Suravee Suthikulpanit
2026-06-01 13:35   ` Jason Gunthorpe [this message]
2026-05-28  5:17 ` [PATCH v2 22/26] iommufd: Add hw_queue_init and split queue alloc paths Suravee Suthikulpanit
2026-05-29  0:14   ` Nicolin Chen
2026-06-03  0:30     ` Suthikulpanit, Suravee
2026-06-01 13:38   ` Jason Gunthorpe
2026-05-28  5:17 ` [PATCH v2 23/26] iommu/amd: Add support for vIOMMU HW queues initialization Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 24/26] iommufd: Introduce vIOMMU command via VIOMMU_COMMAND ioctl Suravee Suthikulpanit
2026-05-28  5:17 ` [PATCH v2 25/26] iommu/amd: Handle set/get command for AMD vIOMMU Suravee Suthikulpanit
2026-05-29 23:20   ` Nicolin Chen
2026-06-03  3:53     ` Suthikulpanit, Suravee
2026-05-28  5:17 ` [PATCH v2 26/26] iommu/amd: Introduce logic to check and enable vIOMMU feature Suravee Suthikulpanit
2026-06-01 13:30 ` [PATCH v2 00/26] iommu/amd: Introduce AMD Hardware-accelerated Virtualized IOMMU (vIOMMU) Support Jason Gunthorpe
2026-06-03  4:13   ` Suthikulpanit, Suravee
2026-06-03  6:41   ` Suthikulpanit, Suravee
2026-06-03 12:13     ` Jason Gunthorpe
2026-06-05  8:41     ` Suthikulpanit, Suravee

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260601133552.GO3195266@nvidia.com \
    --to=jgg@nvidia.com \
    --cc=chriscli@google.com \
    --cc=dantuluris@google.com \
    --cc=iommu@lists.linux.dev \
    --cc=jay.chen@amd.com \
    --cc=jon.grimm@amd.com \
    --cc=joro@8bytes.org \
    --cc=kevin.tian@intel.com \
    --cc=kpsingh@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=nicolinc@nvidia.com \
    --cc=sairaj.arunkodilkar@amd.com \
    --cc=santosh.shukla@amd.com \
    --cc=suravee.suthikulpanit@amd.com \
    --cc=vasant.hegde@amd.com \
    --cc=wnliu@google.com \
    --cc=wvw@google.com \
    --cc=yi.l.liu@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox