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

[Baolu Lu]

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@xxxxxxxxxx>
> > Signed-off-by: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> > ---
> >   include/linux/iommu.h | 4 ++++
> >   1 file changed, 4 insertions(+)
> Reviewed-by: Jason Gunthorpe<jgg@xxxxxxxxxx>
>
> > + * @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