22 Oct
2025
22 Oct
'25
11:38 a.m.
On Wed, Oct 22, 2025 at 12:08:48AM -0700, Christoph Hellwig wrote:
On Mon, Oct 20, 2025 at 10:08:55AM -0300, Jason Gunthorpe wrote:
Sure, but this should be handled by the P2P subsystem and PCI quirks, IMHO. It isn't VFIOs job.. If people complain about broken HW then it is easy to add those things.
I think it is. You now open up behavior generally that previously had specific drivers in charge.
It has always been available in VFIO. This series is fixing it up to not have the lifetime bugs.
IDK where Intel GPU lands on this, but VFIO has always supported P2P
How?
It uses follow_pfnmap_start()/etc to fish the MMIO PFNs out of a VMA and stick them into the iommu.
Jason