Re: [PATCH v3 10/20] iommu: Add set_platform_dma iommu ops

Baolu Lu
2022-11-29T02:22:27Z

On 11/28/22 10:11 PM, Jason Gunthorpe wrote:
> On Mon, Nov 28, 2022 at 02:46:38PM +0800, Lu Baolu wrote:
>> When VFIO finishes assigning a device to user space and calls
>> iommu_group_release_dma_owner() to return the device to kernel, the IOMMU
>> core will attach the default domain to the device. Unfortunately, some
>> IOMMU drivers don't support default domain, hence in the end, the core
>> calls .detach_dev instead.
>>
>> This adds set_platform_dma iommu ops to make it clear that what it does
>> is returning control back to the platform DMA ops.
>>
>> Suggested-by: Jason Gunthorpe<jgg@nvidia.com>
>> Signed-off-by: Lu Baolu<baolu.lu@linux.intel.com>
>> ---
>> include/linux/iommu.h | 4 ++++
>> 1 file changed, 4 insertions(+)
> Reviewed-by: Jason Gunthorpe<jgg@nvidia.com>
>
>> + * @set_platform_dma: Returning control back to the platform DMA ops. Only
>> + * valid for IOMMU drivers which don't support default
>> + * domain.
> I would add:
>
> This op is to support old IOMMU drivers, new drivers should use
> default domains, and the common IOMMU DMA ops.

Done. Thank you!

Best regards,
baolu