linux-kernel - [PATCH v2 3/4] KVM: x86/pmu: Reuse pmc_perf_hw_id() and drop find_fixed

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Message-Id: <20211119064856.77948-4-likexu@tencent.com>
Date:   Fri, 19 Nov 2021 14:48:55 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 3/4] KVM: x86/pmu: Reuse pmc_perf_hw_id() and drop find_fixed_event()

From: Like Xu <likexu@...cent.com>

Since we set the same semantic event value for the fixed counter in
pmc->eventsel, returning the perf_hw_id for the fixed counter via
find_fixed_event() can be painlessly replaced by pmc_perf_hw_id()
with the help of pmc_is_fixed() check.

Signed-off-by: Like Xu <likexu@...cent.com>
---
 arch/x86/kvm/pmu.c           |  2 +-
 arch/x86/kvm/pmu.h           |  1 -
 arch/x86/kvm/svm/pmu.c       | 11 ++++-------
 arch/x86/kvm/vmx/pmu_intel.c | 29 ++++++++++++++++-------------
 4 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 3b3ccf5b1106..b7a1ae28ab87 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -262,7 +262,7 @@ void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int idx)
 
 	pmc->current_config = (u64)ctrl;
 	pmc_reprogram_counter(pmc, PERF_TYPE_HARDWARE,
-			      kvm_x86_ops.pmu_ops->find_fixed_event(idx),
+			      kvm_x86_ops.pmu_ops->pmc_perf_hw_id(pmc),
 			      !(en_field & 0x2), /* exclude user */
 			      !(en_field & 0x1), /* exclude kernel */
 			      pmi, false, false);
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index dd7dbb1c5048..c91d9725aafd 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -25,7 +25,6 @@ struct kvm_event_hw_type_mapping {
 
 struct kvm_pmu_ops {
 	unsigned int (*pmc_perf_hw_id)(struct kvm_pmc *pmc);
-	unsigned (*find_fixed_event)(int idx);
 	bool (*pmc_is_enabled)(struct kvm_pmc *pmc);
 	struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
 	struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu,
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 3c00a34457d7..da8aa1e5bff0 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -140,6 +140,10 @@ static unsigned int amd_pmc_perf_hw_id(struct kvm_pmc *pmc)
 	u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
 	int i;
 
+	/* return PERF_COUNT_HW_MAX as AMD doesn't have fixed events */
+	if (WARN_ON(pmc_is_fixed(pmc)))
+		return PERF_COUNT_HW_MAX;
+
 	for (i = 0; i < ARRAY_SIZE(amd_event_mapping); i++)
 		if (amd_event_mapping[i].eventsel == event_select
 		    && amd_event_mapping[i].unit_mask == unit_mask)
@@ -151,12 +155,6 @@ static unsigned int amd_pmc_perf_hw_id(struct kvm_pmc *pmc)
 	return amd_event_mapping[i].event_type;
 }
 
-/* return PERF_COUNT_HW_MAX as AMD doesn't have fixed events */
-static unsigned amd_find_fixed_event(int idx)
-{
-	return PERF_COUNT_HW_MAX;
-}
-
 /* check if a PMC is enabled by comparing it against global_ctrl bits. Because
  * AMD CPU doesn't have global_ctrl MSR, all PMCs are enabled (return TRUE).
  */
@@ -320,7 +318,6 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)
 
 struct kvm_pmu_ops amd_pmu_ops = {
 	.pmc_perf_hw_id = amd_pmc_perf_hw_id,
-	.find_fixed_event = amd_find_fixed_event,
 	.pmc_is_enabled = amd_pmc_is_enabled,
 	.pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
 	.rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc,
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 67a0188ecdc5..72db4ffb7eb2 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -68,6 +68,19 @@ static void global_ctrl_changed(struct kvm_pmu *pmu, u64 data)
 		reprogram_counter(pmu, bit);
 }
 
+static inline unsigned int intel_find_fixed_event(int idx)
+{
+	u32 event;
+	size_t size = ARRAY_SIZE(fixed_pmc_events);
+
+	if (idx >= size)
+		return PERF_COUNT_HW_MAX;
+
+	event = fixed_pmc_events[array_index_nospec(idx, size)];
+	return intel_arch_events[event].event_type;
+}
+
+
 static unsigned int intel_pmc_perf_hw_id(struct kvm_pmc *pmc)
 {
 	struct kvm_pmu *pmu = pmc_to_pmu(pmc);
@@ -75,6 +88,9 @@ static unsigned int intel_pmc_perf_hw_id(struct kvm_pmc *pmc)
 	u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
 	int i;
 
+	if (pmc_is_fixed(pmc))
+		return intel_find_fixed_event(pmc->idx - INTEL_PMC_IDX_FIXED);
+
 	for (i = 0; i < ARRAY_SIZE(intel_arch_events); i++)
 		if (intel_arch_events[i].eventsel == event_select
 		    && intel_arch_events[i].unit_mask == unit_mask
@@ -87,18 +103,6 @@ static unsigned int intel_pmc_perf_hw_id(struct kvm_pmc *pmc)
 	return intel_arch_events[i].event_type;
 }
 
-static unsigned intel_find_fixed_event(int idx)
-{
-	u32 event;
-	size_t size = ARRAY_SIZE(fixed_pmc_events);
-
-	if (idx >= size)
-		return PERF_COUNT_HW_MAX;
-
-	event = fixed_pmc_events[array_index_nospec(idx, size)];
-	return intel_arch_events[event].event_type;
-}
-
 /* check if a PMC is enabled by comparing it with globl_ctrl bits. */
 static bool intel_pmc_is_enabled(struct kvm_pmc *pmc)
 {
@@ -721,7 +725,6 @@ static void intel_pmu_cleanup(struct kvm_vcpu *vcpu)
 
 struct kvm_pmu_ops intel_pmu_ops = {
 	.pmc_perf_hw_id = intel_pmc_perf_hw_id,
-	.find_fixed_event = intel_find_fixed_event,
 	.pmc_is_enabled = intel_pmc_is_enabled,
 	.pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
 	.rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc,
-- 
2.33.1