Hi Jason, By the way, we have been following progress on IOMMUFD, and would be interested in dogfooding it for our use case when ready. The main blocker is IOMMUFD's current lack of P2P support (IOMMU_IOAS_MAP fails when the VA range is backed by MMIO). dma-buf as a less ambiguous semantic for communicating this intent (rather than the struggles of inferring what kind of memory is behind some VA range) makes a lot of sense. Based on tidbits we have gleaned, IOMMUFD P2P support intends to be built on top of "Provide a new two step DMA mapping API" [1] and "vfio/pci: Allow MMIO regions to be exported through dma-buf" [2]. Item [2] appears to have been picked up by "Host side (KVM/VFIO/IOMMUFD) support for TDISP using TSM" [3]. Is the above understanding correct? On top of this, there would need to be a new IOMMUFD uapi, or extension to existing, which would accept an input dma-buf to map. Are there any patches in progress which include this? [1] https://lore.kernel.org/all/cover.1746424934.git.leon@xxxxxxxxxx/ [2] https://lore.kernel.org/all/20250307052248.405803-1-vivek.kasireddy@xxxxxxxxx [3] https://lore.kernel.org/all/20250529053513.1592088-1-yilun.xu@xxxxxxxxxxxxxxx Thanks, Alex
