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Subject[PATCH kvm/queue v2 2/3] perf: x86/core: Add interface to query perfmon_event_map[] directly
Date
From: Like Xu <likexu@tencent.com>

Currently, we have [intel|knc|p4|p6]_perfmon_event_map on the Intel
platforms and amd_[f17h]_perfmon_event_map on the AMD platforms.

Early clumsy KVM code or other potential perf_event users may have
hard-coded these perfmon_maps (e.g., arch/x86/kvm/svm/pmu.c), so
it would not make sense to program a common hardware event based
on the generic "enum perf_hw_id" once the two tables do not match.

Let's provide an interface for callers outside the perf subsystem to get
the counter config based on the perfmon_event_map currently in use,
and it also helps to save bytes.

Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Like Xu <likexu@tencent.com>
---
arch/x86/events/core.c | 9 +++++++++
arch/x86/include/asm/perf_event.h | 2 ++
2 files changed, 11 insertions(+)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 38b2c779146f..751048f4cc97 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -693,6 +693,15 @@ void x86_pmu_disable_all(void)
}
}

+u64 perf_get_hw_event_config(int perf_hw_id)
+{
+ if (perf_hw_id < x86_pmu.max_events)
+ return x86_pmu.event_map(perf_hw_id);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(perf_get_hw_event_config);
+
struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr)
{
return static_call(x86_pmu_guest_get_msrs)(nr);
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 8fc1b5003713..d1e325517b74 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -492,9 +492,11 @@ static inline void perf_check_microcode(void) { }

#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL)
extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr);
+extern u64 perf_get_hw_event_config(int perf_hw_id);
extern int x86_perf_get_lbr(struct x86_pmu_lbr *lbr);
#else
struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr);
+u64 perf_get_hw_event_config(int perf_hw_id);
static inline int x86_perf_get_lbr(struct x86_pmu_lbr *lbr)
{
return -1;
--
2.33.1
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