Re: [PATCH RFC 10/11] iommu: Make IOPF handling framework generic

Jason Gunthorpe
2022-03-21T12:43:52Z

On Mon, Mar 21, 2022 at 11:42:16AM +0000, Jean-Philippe Brucker wrote:

> I tend to disagree with that last part. The fault is caused by a specific
> device accessing shared page tables. We should keep that device
> information throughout the fault handling, so that we can report it to the
> driver when things go wrong.

SVA faults should never be reported to drivers??

> A process can have multiple threads bound to different devices, they
> share the same mm so if the driver wanted to signal a misbehaving
> thread, similarly to a SEGV on the CPU side, it would need the
> device information to precisely report it to userspace.

I'm not sure I understand this - we can't match DMAs to executing
CPUs. On fault we fail the DMA and let the process keep running or
SIGSEGV the whole thread group.

Jason