On Wed, Jun 23, 2021 at 05:49:55PM -0400, Felix Kuehling wrote: > > I can think of two ways to test the changes for MEMORY_DEVICE_GENERIC in > this patch series in a way that is reproducible without special hardware and > firmware: > > For the reference counting changes we could use the dax driver with hmem and > use efi_fake_mem on the kernel command line to create some DEVICE_GENERIC > pages. I'm open to suggestions for good user mode tests to exercise dax > functionality on this type of memory. Sorry for the thread necromancy, but now that the merge window is past.... Today I test ext4's dax support, without having any $$$ DAX hardware, by using the kernel command line "memmap=4G!9G:memmap=9G!14G" which reserves memory so that creates two pmem device and then I run xfstests with DAX enabled using qemu or using a Google Compute Engine VM, using TEST_DEV=/dev/pmem0 and SCRATCH_DEV=/dev/pmem1. If you can give me a recipe for what kernel configs I should enable, and what magic kernel command line arguments to use, then I'd be able to test your patch set with ext4. Cheers, - Ted