From: Kim Phillips kim.phillips@amd.com
[ Upstream commit e2abfc0448a46d8a137505aa180caf14070ec535 ]
Commit
21b5ee59ef18 ("x86/cpu/amd: Enable the fixed Instructions Retired counter IRPERF")
mistakenly added erratum #1054 as an OS Visible Workaround (OSVW) ID 0. Erratum #1054 is not OSVW ID 0 [1], so make it a legacy erratum.
There would never have been a false positive on older hardware that has OSVW bit 0 set, since the IRPERF feature was not available.
However, save a couple of RDMSR executions per thread, on modern system configurations that correctly set non-zero values in their OSVW_ID_Length MSRs.
[1] Revision Guide for AMD Family 17h Models 00h-0Fh Processors. The revision guide is available from the bugzilla link below.
Fixes: 21b5ee59ef18 ("x86/cpu/amd: Enable the fixed Instructions Retired counter IRPERF") Reported-by: Andrew Cooper andrew.cooper3@citrix.com Signed-off-by: Kim Phillips kim.phillips@amd.com Signed-off-by: Borislav Petkov bp@suse.de Link: https://lkml.kernel.org/r/20200417143356.26054-1-kim.phillips@amd.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/cpu/amd.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 120769955687..de69090ca142 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -1122,8 +1122,7 @@ static const int amd_erratum_383[] =
/* #1054: Instructions Retired Performance Counter May Be Inaccurate */ static const int amd_erratum_1054[] = - AMD_OSVW_ERRATUM(0, AMD_MODEL_RANGE(0x17, 0, 0, 0x2f, 0xf)); - + AMD_LEGACY_ERRATUM(AMD_MODEL_RANGE(0x17, 0, 0, 0x2f, 0xf));
static bool cpu_has_amd_erratum(struct cpuinfo_x86 *cpu, const int *erratum) {