On 7/31/2020 12:56 PM, Jason Gunthorpe wrote: > On Fri, Jul 31, 2020 at 12:11:52PM -0400, Steven Sistare wrote: >>> Your preservation-across-exec use-case might or might not need the >>> VMA to be mapped at the same address. >> >> It does. qemu registers memory with vfio which remembers the va's in kernel >> metadata for the device. > > Once the memory is registered with vfio the VA doesn't matter, vfio > will keep the iommu pointing at the same physical pages no matter > where they are mapped. Yes, but there are other code paths that compute and use offsets between va and the base va. Mapping at a different va in the new process breaks vfio; I have tried it. - Steve
