x86/events/intel: Do not deploy TSX force abort workaround when TSX is deprecated

Earlier workaround added by

  400816f60c54 ("perf/x86/intel: Implement support for TSX Force Abort")

for perf counter interactions [1] are not required on some client
systems which received a microcode update that deprecates TSX.

Bypass the perf workaround when such microcode is enumerated.

[1] [ bp: Look for document ID 604224, "Performance Monitoring Impact
      of Intel Transactional Synchronization Extension Memory". Since
      there's no way for us to have stable links to documents... ]

 [ bp: Massage comment. ]

Signed-off-by: Pawan Gupta <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Reviewed-by: Andi Kleen <[email protected]>
Reviewed-by: Tony Luck <[email protected]>
Tested-by: Neelima Krishnan <[email protected]>
Link: https://lkml.kernel.org/r/e4d410f786946280ced02dd07c74e0a74f1d10cb.1623704845.git-series.pawan.kumar.gupta@linux.intel.com

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 2521d03de5e02e9f347e09edda033cbd0a6e9ede..062bf8968c0e50e916e9b04249ff42cacb3a3223 100644 (file)
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -6015,7 +6015,13 @@ __init int intel_pmu_init(void)
                tsx_attr = hsw_tsx_events_attrs;
                intel_pmu_pebs_data_source_skl(pmem);
 
-               if (boot_cpu_has(X86_FEATURE_TSX_FORCE_ABORT)) {
+               /*
+                * Processors with CPUID.RTM_ALWAYS_ABORT have TSX deprecated by default.
+                * TSX force abort hooks are not required on these systems. Only deploy
+                * workaround when microcode has not enabled X86_FEATURE_RTM_ALWAYS_ABORT.
+                */
+               if (boot_cpu_has(X86_FEATURE_TSX_FORCE_ABORT) &&
+                  !boot_cpu_has(X86_FEATURE_RTM_ALWAYS_ABORT)) {
                        x86_pmu.flags |= PMU_FL_TFA;
                        x86_pmu.get_event_constraints = tfa_get_event_constraints;
                        x86_pmu.enable_all = intel_tfa_pmu_enable_all;