perf/x86/intel: Don't enable freeze-on-smi for PerfMon V1

The SMM freeze feature was introduced since PerfMon V2. But the current
code unconditionally enables the feature for all platforms. It can
generate #GP exception, if the related FREEZE_WHILE_SMM bit is set for
the machine with PerfMon V1.

To disable the feature for PerfMon V1, perf needs to
- Remove the freeze_on_smi sysfs entry by moving intel_pmu_attrs to
  intel_pmu, which is only applied to PerfMon V2 and later.
- Check the PerfMon version before flipping the SMM bit when starting CPU

Fixes: 6089327f5424 ("perf/x86: Add sysfs entry to freeze counters on SMI")
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ak@linux.intel.com
Cc: eranian@google.com
Cc: acme@redhat.com
Link: https://lkml.kernel.org/r/1524682637-63219-1-git-send-email-kan.liang@linux.intel.com

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 607bf565a90c97c3d0d72bf979fdf88cf10c8e28..707b2a96e516b5579c9321cbf0822a627bc8a8d8 100644 (file)
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3339,7 +3339,8 @@ static void intel_pmu_cpu_starting(int cpu)
 
        cpuc->lbr_sel = NULL;
 
-       flip_smm_bit(&x86_pmu.attr_freeze_on_smi);
+       if (x86_pmu.version > 1)
+               flip_smm_bit(&x86_pmu.attr_freeze_on_smi);
 
        if (!cpuc->shared_regs)
                return;
@@ -3502,6 +3503,8 @@ static __initconst const struct x86_pmu core_pmu = {
        .cpu_dying              = intel_pmu_cpu_dying,
 };
 
+static struct attribute *intel_pmu_attrs[];
+
 static __initconst const struct x86_pmu intel_pmu = {
        .name                   = "Intel",
        .handle_irq             = intel_pmu_handle_irq,
@@ -3533,6 +3536,8 @@ static __initconst const struct x86_pmu intel_pmu = {
        .format_attrs           = intel_arch3_formats_attr,
        .events_sysfs_show      = intel_event_sysfs_show,
 
+       .attrs                  = intel_pmu_attrs,
+
        .cpu_prepare            = intel_pmu_cpu_prepare,
        .cpu_starting           = intel_pmu_cpu_starting,
        .cpu_dying              = intel_pmu_cpu_dying,
@@ -3911,8 +3916,6 @@ __init int intel_pmu_init(void)
 
        x86_pmu.max_pebs_events         = min_t(unsigned, MAX_PEBS_EVENTS, x86_pmu.num_counters);
 
-
-       x86_pmu.attrs                   = intel_pmu_attrs;
        /*
         * Quirk: v2 perfmon does not report fixed-purpose events, so
         * assume at least 3 events, when not running in a hypervisor: