Re: [PATCH v6 2/6] iommufd: Add IOMMU_HWPT_INVALIDATE

[Jason Gunthorpe]

On Tue, Dec 05, 2023 at 09:33:30AM -0800, Nicolin Chen wrote:
> On Mon, Dec 04, 2023 at 10:48:50AM -0400, Jason Gunthorpe wrote:
>  
> > > Or am I missing some point here?
> > 
> > It sounds Ok, we just have to understand what userspace should be
> > doing and how much of this the kernel should implement.
> > 
> > It seems to me that the error code should return the gerror and the
> > req_num should indicate the halted cons. The vmm should relay both
> > into the virtual registers.
> 
> I see your concern. I will take a closer look and see if we can
> add to the initial version of arm_smmu_cache_invalidate_user().
> Otherwise, we can add later.
> 
> Btw, VT-d seems to want the error_code and reports in the VT-d
> specific invalidate entry structure, as Kevin and Yi had that
> discussion in the other side of the thread.

It could be fine to shift it into the driver data blob. It isn't
really generic in the end.

Jason