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