On Thu, 8 Jan 2026 10:10:44 -0400 Jason Gunthorpe jgg@ziepe.ca wrote:
On Wed, Jan 07, 2026 at 06:41:10PM -0800, Alex Mastro wrote:
On Wed, Jan 07, 2026 at 08:54:06PM -0400, Jason Gunthorpe wrote:
On Wed, Jan 07, 2026 at 11:54:09PM +0000, David Matlack wrote:
On 2026-01-07 02:13 PM, Alex Mastro wrote:
Test MMIO-backed DMA mappings by iommu_map()-ing mmap'ed BAR regions.
Thanks for adding this!
Also update vfio_pci_bar_map() to align BAR mmaps for efficient huge page mappings.
Only vfio_type1 variants are tested; iommufd variants can be added once kernel support lands.
Are there plans to support mapping BARs via virtual address in iommufd? I thought the plan was only to support via dma-bufs. Maybe Jason can confirm.
Only dmabuf.
Ack. I got confused. I had thought iommufd's vfio container compatibility mode was going to support this, but realized that doesn't make sense given past discussions about the pitfalls of achieving these mappings the legacy way.
Oh, I was thinking about a compatability only flow only in the type 1 emulation that internally magically converts a VMA to a dmabuf, but I haven't written anything.. It is a bit tricky and the type 1 emulation has not been as popular as I expected??
In part because of this gap, I'd guess. Thanks,
Alex