perf/x86/amd: Warn only on new bits set
Warning at every leaking bits can cause a flood of message, triggering
various stall-warning mechanisms to fire, including CSD locks, which
makes the machine to be unusable.
Track the bits that are being leaked, and only warn when a new bit is
set.
That said, this patch will help with the following issues:
1) It will tell us which bits are being set, so, it is easy to
communicate it back to vendor, and to do a root-cause analyzes.
2) It avoid the machine to be unusable, because, worst case
scenario, the user gets less than 60 WARNs (one per unhandled bit).
Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sandipan Das <sandipan.das@amd.com>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/20241001141020.2620361-1-leitao@debian.org