On Thu, Aug 10, 2023 at 10:27:21AM +0800, Baolu Lu wrote: > On 2023/8/10 0:59, Jason Gunthorpe wrote: > > On Thu, Jul 27, 2023 at 01:48:28PM +0800, Lu Baolu wrote: > > > The unrecoverable fault data is not used anywhere. Remove it to avoid > > > dead code. > > > > > > Suggested-by: Kevin Tian<kevin.tian@xxxxxxxxx> > > > Signed-off-by: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx> > > > --- > > > include/linux/iommu.h | 70 +------------------------------------------ > > > 1 file changed, 1 insertion(+), 69 deletions(-) > > Do we plan to bring this back in some form? A driver specific fault > > report via iommufd? > > I can hardly see the possibility. > > The only necessary dma fault messages are the offending address and the > permissions. With these, the user space device model software knows that > "a DMA fault was generated when the IOMMU hardware tried to translate > the offending address with the given permissions". > > And then, the device model software will walk the page table and figure > out what is missed before injecting the vendor-specific fault messages > to the VM guest. Avoiding walking the page table sounds like a pretty big win if we could manage it by forwarding more event data.. Jason
