On Thu, Mar 04, 2021 at 03:11:08PM -0800, Rob Clark wrote:

On Thu, Mar 4, 2021 at 7:48 AM Robin Murphy [off-list ref] wrote:

quoted

On 2021-03-01 08:42, Christoph Hellwig wrote:

quoted

Signed-off-by: Christoph Hellwig <hch@lst.de>

Moreso than the previous patch, where the feature is at least relatively
generic (note that there's a bunch of in-flight development around
DOMAIN_ATTR_NESTING), I'm really not convinced that it's beneficial to
bloat the generic iommu_ops structure with private driver-specific
interfaces. The attribute interface is a great compromise for these
kinds of things, and you can easily add type-checked wrappers around it
for external callers (maybe even make the actual attributes internal
between the IOMMU core and drivers) if that's your concern.

I suppose if this is *just* for the GPU we could move it into adreno_smmu_priv..

But one thing I'm not sure about is whether
IO_PGTABLE_QUIRK_ARM_OUTER_WBWA is something that other devices
*should* be using as well, but just haven't gotten around to yet.

The intention is certainly that this would be a place to collate per-domain
pgtable quirks, so I'd prefer not to tie that to the GPU.

Will