perf/x86/rapl: Add msr mask support

In some cases, when probing a perf MSR, we're probing certain bits of the
MSR instead of the whole register, thus only these bits should be checked.

For example, for RAPL ENERGY_STATUS MSR, only the lower 32 bits represents
the energy counter, and the higher 32bits are reserved.

Introduce a new mask field in struct perf_msr to allow probing certain
bits of a MSR.

This change is transparent to the current perf_msr_probe() users.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/20210204161816.12649-1-rui.zhang@intel.com

diff --git a/arch/x86/events/probe.c b/arch/x86/events/probe.c
index 136a1e8..600bf8d 100644 (file)
--- a/arch/x86/events/probe.c
+++ b/arch/x86/events/probe.c
@@ -28,6 +28,7 @@ perf_msr_probe(struct perf_msr *msr, int cnt, bool zero, void *data)
        for (bit = 0; bit < cnt; bit++) {
                if (!msr[bit].no_check) {
                        struct attribute_group *grp = msr[bit].grp;
+                       u64 mask;
 
                        /* skip entry with no group */
                        if (!grp)
@@ -44,8 +45,12 @@ perf_msr_probe(struct perf_msr *msr, int cnt, bool zero, void *data)
                        /* Virt sucks; you cannot tell if a R/O MSR is present :/ */
                        if (rdmsrl_safe(msr[bit].msr, &val))
                                continue;
+
+                       mask = msr[bit].mask;
+                       if (!mask)
+                               mask = ~0ULL;
                        /* Disable zero counters if requested. */
-                       if (!zero && !val)
+                       if (!zero && !(val & mask))
                                continue;
 
                        grp->is_visible = NULL;

diff --git a/arch/x86/events/probe.h b/arch/x86/events/probe.h
index 4c8e0af..261b9bd 100644 (file)
--- a/arch/x86/events/probe.h
+++ b/arch/x86/events/probe.h
@@ -4,10 +4,11 @@
 #include <linux/sysfs.h>
 
 struct perf_msr {
-       u64                       msr;
-       struct attribute_group   *grp;
+       u64                     msr;
+       struct attribute_group  *grp;
        bool                    (*test)(int idx, void *data);
-       bool                      no_check;
+       bool                    no_check;
+       u64                     mask;
 };
 
 unsigned long