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

[Jean-Philippe Brucker]

On Tue, Mar 22, 2022 at 01:03:14PM +0800, Lu Baolu wrote:
> On 2022/3/21 20:43, Jason Gunthorpe wrote:
> > 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??
> > 
> 
> When things go wrong, the corresponding response code will be responded
> to the device through iommu_page_response(). The hardware should then
> report the failure to the device driver and the device driver will
> handle it in the device-specific way. There's no need to propagate the
> I/O page faults to the device driver in any case. Do I understand it
> right?

In theory yes, but devices don't necessarily have the ability to report
precise errors, we may have more information.

Thanks,
Jean