Check keys when emulating instructions and let user space do key checked
accesses.
User space can do so via an extension of the MEMOP IOCTL:
* allow optional key checking
* allow MEMOP on vm fd, so key checked accesses on absolute memory
become possible
I haven't finished the memop selftest rewrite, but decided to send out a
new version anyway, since the functional patches are (hopefully) final
and the memop selftest patch works. I'll reply to it with the
rewritten version.
v3: https://lore.kernel.org/kvm/20220209170422.1910690-1-scgl@xxxxxxxxxxxxx/
v2: https://lore.kernel.org/kvm/20220207165930.1608621-1-scgl@xxxxxxxxxxxxx/
v3 -> v4
* rebase
* ignore key in memop if skey flag not specified
* fix nits in documentation
* pick up tags