From: Jason Gunthorpe <jgg@ziepe.ca>
To: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Samiullah Khawaja <skhawaja@google.com>,
David Woodhouse <dwmw2@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
iommu@lists.linux.dev, YiFei Zhu <zhuyifei@google.com>,
Robin Murphy <robin.murphy@arm.com>,
Pratyush Yadav <pratyush@kernel.org>,
Kevin Tian <kevin.tian@intel.com>,
linux-kernel@vger.kernel.org, Saeed Mahameed <saeedm@nvidia.com>,
Adithya Jayachandran <ajayachandra@nvidia.com>,
Parav Pandit <parav@nvidia.com>,
Leon Romanovsky <leonro@nvidia.com>, William Tu <witu@nvidia.com>,
Vipin Sharma <vipinsh@google.com>,
dmatlack@google.com, Chris Li <chrisl@kernel.org>,
praan@google.com
Subject: Re: [RFC PATCH 13/15] iommufd: Persist iommu domains for live update
Date: Tue, 30 Sep 2025 13:31:11 -0300 [thread overview]
Message-ID: <20250930163111.GO2695987@ziepe.ca> (raw)
In-Reply-To: <CA+CK2bAtChLRVyQftBMN18SKt2o7FcV0q-YUcPS9ZKn2qD87mg@mail.gmail.com>
On Tue, Sep 30, 2025 at 11:09:59AM -0400, Pasha Tatashin wrote:
>
> The way LUOv4 is implemented, "LUO sessions" are always participating
> LU. Once a user adds file descriptors to a session, that session and
> its contents are automatically carried across multiple consecutive
> live updates. The user only needs to act if they explicitly want to
> remove an FD and opt-out of preservation, or close session. This is
> consistent and convenient for long-running VM that should survive by
> default.
I don't think this is a good idea. Each kernel should decide on its
own what and how things get included and manage the labels, from
scratch.
If you do this then alot more stuff becomes ABI and I think it will
turn into a huge PITA.
The userspace already has to have the code to setup the luo if it is
on a clean reboot - what is the point of not running that every time?
Jason
next prev parent reply other threads:[~2025-09-30 16:31 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-28 19:06 [RFC PATCH 00/15] iommu: Add live update state preservation Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 01/15] iommu/vt-d: Register with Live Update Orchestrator Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 02/15] iommu: Add rw_semaphore to serialize live update state Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 03/15] iommu/vt-d: Prevent hotplugs when live update state is not normal Samiullah Khawaja
2025-09-29 15:51 ` Jason Gunthorpe
2025-09-29 16:50 ` Pasha Tatashin
2025-09-29 17:21 ` Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 04/15] iommu: Add preserve iommu_domain op Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 05/15] iommu: Introduce API to preserve iommu domain Samiullah Khawaja
2025-09-29 15:54 ` Jason Gunthorpe
2025-09-29 18:11 ` Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 06/15] iommu/vt-d: Add stub intel iommu domain preserve op Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 07/15] iommu/vt-d: Add implementation of live update prepare callback Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 08/15] iommu/vt-d: Implement live update preserve_iommu_context Samiullah Khawaja
2025-09-29 15:57 ` Jason Gunthorpe
2025-09-28 19:06 ` [RFC PATCH 09/15] iommu/vt-d: Add live update freeze callback Samiullah Khawaja
2025-09-29 15:58 ` Jason Gunthorpe
2025-09-28 19:06 ` [RFC PATCH 10/15] iommu/vt-d: Restore iommu root_table and context on live update Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 11/15] iommufd: Add basic skeleton based on liveupdate_file_handle Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 12/15] iommufd-luo: Implement basic prepare/cancel/finish/retrieve using folios Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 13/15] iommufd: Persist iommu domains for live update Samiullah Khawaja
2025-09-29 16:00 ` Jason Gunthorpe
2025-09-29 17:32 ` Samiullah Khawaja
2025-09-29 17:43 ` Jason Gunthorpe
2025-09-29 17:45 ` Pasha Tatashin
2025-09-30 13:07 ` Pasha Tatashin
2025-09-30 13:59 ` Jason Gunthorpe
2025-09-30 15:09 ` Pasha Tatashin
2025-09-30 16:31 ` Jason Gunthorpe [this message]
2025-09-30 20:02 ` Samiullah Khawaja
2025-09-30 21:05 ` Jason Gunthorpe
2025-09-30 23:15 ` Samiullah Khawaja
2025-10-01 11:47 ` Jason Gunthorpe
2025-10-01 19:28 ` Pasha Tatashin
2025-10-02 11:57 ` Jason Gunthorpe
2025-10-02 14:43 ` Pasha Tatashin
2025-10-02 15:10 ` Jason Gunthorpe
2025-10-02 19:29 ` Samiullah Khawaja
2025-10-02 21:12 ` Jason Gunthorpe
2025-10-02 21:30 ` Pasha Tatashin
2025-10-02 22:58 ` Jason Gunthorpe
2025-10-02 23:56 ` Samiullah Khawaja
2025-10-03 12:09 ` Jason Gunthorpe
2025-10-02 1:00 ` Samiullah Khawaja
2025-10-02 13:41 ` Jason Gunthorpe
2025-10-02 14:59 ` Pasha Tatashin
2025-10-02 17:03 ` Samiullah Khawaja
2025-10-02 17:37 ` Jason Gunthorpe
2025-10-02 18:08 ` Samiullah Khawaja
2025-10-10 1:28 ` Pasha Tatashin
2025-10-10 14:24 ` Jason Gunthorpe
2025-09-28 19:06 ` [RFC PATCH 14/15] iommu/vt-d: sanitize restored root table and iommu contexts Samiullah Khawaja
2025-09-28 19:06 ` [RFC PATCH 15/15] iommufd/selftest: Add test to verify iommufd preservation Samiullah Khawaja
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