On Thu, Jul 18, 2024 at 09:50:31AM +0800, Yan Zhao wrote: > Ok. Then if we have two sets of pfns, then we can > 1. Call remap_pfn_range() in mmap() for pfn set 1. I don't think this will work.. At least from the current implementation, remap_pfn_range() will only reserve the memtype if the range covers the whole vma. > 2. Export track_pfn_remap() and call track_pfn_remap() in mmap() for pfn > set 2. > 3. Unmap and call vmf_insert_pfn() in the fault handler to map pfn set 2. IMO this should be the similar case of MMIO being disabled on the bar, where we can use track_pfn_remap() to register the whole vma in mmap() first. Then in this case if you prefer proactive injection of partial of the pfn mappings, one can do that via vmf_insert_pfn*() in mmap() after the memtype registered. > > However, I'm not sure if we can properly untrack both pfn sets 1 and 2. Untrack should so far only happen per-vma, AFAIU, so "set 1+2" need to be done together as they belong to the same vma. > > By exporting untrack_pfn() too? Or, you'll leave VFIO to use ioremap/iounmap() > (or the variants) to reserve memtype by itself? Thanks, -- Peter Xu
