On Mon, Feb 12, 2024 at 07:07:25PM -0800, Sean Christopherson wrote: > On Wed, Jan 03, 2024, Yan Zhao wrote: > > This is a v2 for previous series [1] to allow mapping for compound tail > > pages for IO or PFNMAP mapping. > > > > Compared to v1, this version provides selftest to check functionality in > > KVM to map memslots for MMIO BARs (VMAs with flag VM_IO | VM_PFNMAP), as > > requested by Sean in [1]. > > Doh. So I didn't intend for you to have to create a mock device just to be able > to run a selftest. I assumed it would be easy-ish to utilize an existing generic > device. I take it that's not the case? The selftest requires a vma with flag (VM_IO | VM_PFNMAP) with non-reserved pages as backend. Without a mock device, I don't find a easy way to let the selftest take effect. So, I borrowed the way in "tools/testing/selftests/mm/hmm-tests.c" which uses a mock driver in "lib/test_hmm.c".