Re: [PATCH v8 12/15] iommufd/viommu: Allow PCI TSM backends to provide vIOMMU operations

[sashiko-bot@kernel.org]

> In confidential-computing configurations, a vIOMMU may be implemented by
> a TEE Security Manager rather than by the physical IOMMU driver. Such an
> implementation also needs the TSM identity when creating and validating
> vdevices.
> 
> Allow VIOMMU_ALLOC to first query the TSM associated with the target PCI
> device for vIOMMU operations. Fall back to the physical IOMMU driver
> when the TSM does not provide operations for the requested vIOMMU type.
> 
> Resolve the PCI TSM association under pci_tsm_rwsem, pin the module
> providing the operations, and take a TSM device reference. Store the TSM
> device in the vIOMMU and release both references on allocation failure,
> fallback to the physical IOMMU driver, or vIOMMU destruction. Keep the
> module pinned until after dropping the device reference, since the final
> put may release the TSM device.
> [ ... ]
> Cc: Robin Murphy <robin.murphy@arm.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: iommu@lists.linux.dev
> Cc: linux-pci@vger.kernel.org
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>

Sashiko has reviewed this patch and found no issues.

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