linux-stable/arch/x86/events
Jim Mattson ab112cc573 perf/x86/kvm: Fix Broadwell Xeon stepping in isolation_ucodes[]
[ Upstream commit 4b2f1e5922 ]

The only stepping of Broadwell Xeon parts is stepping 1. Fix the
relevant isolation_ucodes[] entry, which previously enumerated
stepping 2.

Although the original commit was characterized as an optimization, it
is also a workaround for a correctness issue.

If a PMI arrives between kvm's call to perf_guest_get_msrs() and the
subsequent VM-entry, a stale value for the IA32_PEBS_ENABLE MSR may be
restored at the next VM-exit. This is because, unbeknownst to kvm, PMI
throttling may clear bits in the IA32_PEBS_ENABLE MSR. CPUs with "PEBS
isolation" don't suffer from this issue, because perf_guest_get_msrs()
doesn't report the IA32_PEBS_ENABLE value.

Fixes: 9b545c04ab ("perf/x86/kvm: Avoid unnecessary work in guest filtering")
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Peter Shier <pshier@google.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/20210422001834.1748319-1-jmattson@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-28 13:40:00 +02:00
..
amd x86/events/amd/iommu: Fix sizeof mismatch 2020-10-03 16:30:56 +02:00
intel perf/x86/kvm: Fix Broadwell Xeon stepping in isolation_ucodes[] 2021-04-28 13:40:00 +02:00
zhaoxin x86/perf: Fix a typo 2020-07-22 10:22:08 +02:00
core.c These are the performance events changes for v5.10: 2020-10-12 14:14:35 -07:00
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
Makefile perf/x86/rapl: Fix RAPL config variable bug 2020-06-02 11:52:56 +02:00
msr.c perf/x86/msr: Add Jasper Lake support 2020-09-29 09:57:02 +02:00
perf_event.h perf/x86/intel: Make anythread filter support conditional 2020-11-09 18:12:36 +01:00
probe.c perf/x86/rapl: Make perf_probe_msr() more robust and flexible 2020-05-28 07:58:55 +02:00
probe.h perf/x86: Add MSR probe interface 2019-06-24 19:28:31 +02:00
rapl.c perf/x86: fix sysfs type mismatches 2020-11-17 13:15:38 +01:00