[LTP] [PATCH v2 4/7] KVM: Add async communication helper functions

[Petr Vorel]

Hi Martin,

> Some KVM tests need to communicate with VM controller program
> without stopping guest execution. Add guest helper functions
> for sending asynchronous guest signal to host and waiting for host
> to acknowledge the signal. Add host helper functions for waiting
> for guest signal and acknowledging it.

> Test programs using these functions must have at least two host threads.
IMHO we don't have flags to require this. I guess KVM hosts nowadays should have
more than 2 threads (these tests are for bare metal), thus we don't have to note
this also in the code, right?

Anyway LGTM.
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Waiting some time if Cyril, or somebody else will have time to look into this
change before merging whole patchset.

NOTE: whoever will merge this, it requires to change second commit:
https://lore.kernel.org/ltp/20230526142745.GA813136@pevik/

Kind regards,
Petr