From: "Palik, Imre" <[email protected]>

This patch has been added to the 3.18 stable tree. If you have any
objections, please let us know.

===============

[ Upstream commit 2c33645d366d13b969d936b68b9f4875b1fdddea ]

Architectural performance monitoring, version 1, doesn't support fixed counters.

Currently, even if a hypervisor advertises support for architectural
performance monitoring version 1, perf may still try to use the fixed
counters, as the constraints are set up based on the CPU model.

This patch ensures that perf honors the architectural performance monitoring
version returned by CPUID, and it only uses the fixed counters for version 2
and above.

(Some of the ideas in this patch came from Peter Zijlstra.)

Signed-off-by: Imre Palik <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Anthony Liguori <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 arch/x86/kernel/cpu/perf_event_intel.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel.c 
b/arch/x86/kernel/cpu/perf_event_intel.c
index 498b6d9..df11583 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -2604,13 +2604,13 @@ __init int intel_pmu_init(void)
                 * counter, so do not extend mask to generic counters
                 */
                for_each_event_constraint(c, x86_pmu.event_constraints) {
-                       if (c->cmask != FIXED_EVENT_FLAGS
-                           || c->idxmsk64 == INTEL_PMC_MSK_FIXED_REF_CYCLES) {
-                               continue;
+                       if (c->cmask == FIXED_EVENT_FLAGS
+                           && c->idxmsk64 != INTEL_PMC_MSK_FIXED_REF_CYCLES) {
+                               c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 
1;
                        }
-
-                       c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1;
-                       c->weight += x86_pmu.num_counters;
+                       c->idxmsk64 &=
+                               ~(~0UL << (INTEL_PMC_IDX_FIXED + 
x86_pmu.num_counters_fixed));
+                       c->weight = hweight64(c->idxmsk64);
                }
        }
 
-- 
2.1.4

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