perf/amd/ibs: Enable RIP bit63 hardware filtering

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IBS on future hardware adds the ability to filter IBS events by examining
RIP bit 63. Because Linux kernel addresses always have bit 63 set while
user-space addresses never do, this capability can be used as a privilege
filter.

So far, IBS supports privilege filtering in software (swfilt=1), where
samples are dropped in the NMI handler. The RIP bit63 hardware filter
enables IBS to be usable by unprivileged users without passing swfilt
flag. So, swfilt flag will silently be ignored when the hardware
filtering capability is present.

Example (non-root user):
  $ perf record -e ibs_op//u -- <workload>

Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260216042530.1546-6-ravi.bangoria@amd.com

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Ravi Bangoria 2026-02-16 04:25:28 +00:00 • committed by Peter Zijlstra

parent 35247fa60b

commit 8c63c4af92

1 changed files with 38 additions and 8 deletions

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arch/x86/events/amd/ibs.c

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