x86 mmiotrace: WARN_ONCE if dis/arming a page fails

x86 mmiotrace: WARN_ONCE if dis/arming a page fails

Print a full warning once, if arming or disarming a page fails.

Also, if initial arming fails, do not handle the page further. This
avoids the possibility of a page failing to arm and then later claiming
to have handled any fault on that page.

WARN_ONCE added by Pekka Paalanen.

Signed-off-by: Stuart Bennett <[email protected]>
Signed-off-by: Pekka Paalanen <[email protected]>
Cc: Steven Rostedt <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>