Re: [PATCH 03/12] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu()

Jason Gunthorpe via iommu
2022-05-27T15:01:17Z

On Fri, May 27, 2022 at 02:30:10PM +0800, Lu Baolu wrote:
> The disable_dmar_iommu() is called when IOMMU initialzation fails or
> the IOMMU is hot-removed from the system. In both cases, there is no
> need to clear the IOMMU translation data structures for devices.
>
> On the initialization path, the device probing only happens after the
> IOMMU is initialized successfully, hence there're no translation data
> structures.
>
> On the hot-remove path, there is no real use case where the IOMMU is
> hot-removed, but the devices that it manages are still alive in the
> system. The translation data structures were torn down during device
> release, hence there's no need to repeat it in IOMMU hot-remove path
> either.

Can you leave behind a 1 statement WARN_ON of some kind to check this?

Jason