I briefly talked with Jemore about hmm tests, and he said that there are some tests that try to exercise hmm like a driver would, but in software. They also test memory migration. It is better than nothing and it is something we can grow. They are part of tools/testing/selftests/vm/ in kernel tree and lib/test_hmm.c. Discussed this with ddutile over email and he asked to file this BZ to add those to the mm CI.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (Moderate: kernel security, bug fix, and enhancement update), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2022:7683