On Thu, Nov 10, 2022 at 12:32:06PM +0100, Heiko Carstens wrote:
That's why I asked about cmpxchg.h. If you don't want non-cosmetic changes to the existing cmpxchg function and consistency of the new key checked function, then obviously the loop condition needs to be the same.
Such a change is fine of course, even though compare-and-swap for one and two byte patterns don't really matter. I would appreciate if you could send one or two patches on-top of this series which adds the improved logic to (now) both variants.
And, since the question will come up anyway: as soon as we agreed on a complete patch series, I think we should go for a features branch on s390's kernel.org tree which would contain the first five patches sent by me plus potential addon patches provided by you. This tree can then be pulled in by the kvms390 tree where your kvm specific patches can then be applied on top.
FWIW, pushed a non-stable work-in-progress branch to git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git wip/cmpxchg_user_key
This includes also an updated patch, which fixes the missing shift of the access key.