Re: [PATCH v3] io: add io_pgtable abstraction

[Jason Gunthorpe]

On Fri, Dec 12, 2025 at 10:41:05AM +0100, Boris Brezillon wrote:

> > Then you can think about what is ideal for GPU and consider what the
> > work would be like. My uneducated feeling is with gpuvm trying to be
> > common code it could also have gpuvm provide shared common code that
> > directly builds page tables in CPU memory using the above framework.
> 
> So, gpuvm is one level up (it doesn't deal at all with any HW
> representation), but I guess we could provide helpers for UMA-GPUs,
> where preparing the page table on the CPU is a thing, and it could be
> that MSM would be interested in using those helpers too.

You can make it work like the iommu does where gpuvm gets a "gpu
domain" from the driver that is created by using the common code from
gpuvm. Then most of the code is common.

I think something could be built that works with the framebuffer
resident page tables too if they are being accessed over mmio.

Jason