virtio: clean up memory barrier usage
cleanup memory barrier usage bringing it
in sync with what linux guest does.
The rules are simple:
- read barrier after index read
- write barrier before index write
Also, call macros smp_rmb/smp_wmb to stress
we are not syncing with a real io device here.
While I don't think compiler is crazy/powerful
enough to reorder these, anyway, the bogus
barriers we currently have in code will confuse
anyone who tries to copy/reuse it.
Signed-off-by: Michael S. Tsirkin <firstname.lastname@example.org>
Cc: Gleb Natapov <email@example.com>
2 files changed