linux-kernel - Re: [PATCH v1 02/20] iommu: Introduce a test

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Message-ID: <20251103185400.GA1537560@nvidia.com>
Date: Mon, 3 Nov 2025 14:54:00 -0400
From: Jason Gunthorpe <jgg@...dia.com>
To: Nicolin Chen <nicolinc@...dia.com>
Cc: "Tian, Kevin" <kevin.tian@...el.com>,
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Subject: Re: [PATCH v1 02/20] iommu: Introduce a test_dev domain op and an
 internal helper

On Thu, Oct 30, 2025 at 12:43:59PM -0700, Nicolin Chen wrote:

> FWIW, I am thinking of another design based on Jason's remarks:
> https://lore.kernel.org/linux-iommu/aQBopHFub8wyQh5C@Asurada-Nvidia/
> 
> So, instead of core initiating the round trip between the blocking
> domain and group->domain, it forwards dev_reset_prepare/done to the
> driver where it does a low-level attachment that wouldn't fail:
>   For SMMUv3, it's an STE update.
>   For intel_iommu, it seems to be the context table update?

Kevin, how bad do you think the UAPI issue is if we ignore it?

Jason