Re: [RFC PATCH 06/12] iommu: Add mmu_notifier to sva domain

[Jason Gunthorpe]

On Tue, Oct 17, 2023 at 11:20:39AM +0800, Tina Zhang wrote:
> Devices attached to shared virtual addressing (SVA) domain are allowed to
> use the same virtual addresses with processor, and this functionality is
> called shared virtual memory. When shared virtual memory is being used,
> it's the sva domain's responsibility to keep device TLB cache and the CPU
> cache in sync. Hence add mmu_notifier to sva domain.
> 
> Signed-off-by: Tina Zhang <tina.zhang@xxxxxxxxx>
> ---
>  include/linux/iommu.h | 2 ++
>  1 file changed, 2 insertions(+)

You should look at how arm smmuv3 ended up after I went over it to
make similar changes, I think you should take this patch

https://lore.kernel.org/linux-iommu/20-v1-afbb86647bbd+5-smmuv3_newapi_p2_jgg@xxxxxxxxxx/

into this series (maybe drop the arm part)

And copy the same basic structure for how the mmu notifier works.

It would also be nice if alot of the 'if_sva' tests could be avoided,
smmu didn't end up with those..

In the guts of the pasid handling sva shouldn't be special beyond a
different source for the pgd.

Jason