linux-kernel - [PATCH] KVM: x86/pmu: Manipulate FIXED_CTR

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Date:   Tue,  8 Aug 2023 13:15:02 +0800
From:   Dapeng Mi <dapeng1.mi@...ux.intel.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Like Xu <likexu@...cent.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Zhenyu Wang <zhenyuw@...ux.intel.com>,
        Zhang Xiong <xiong.y.zhang@...el.com>,
        Lv Zhiyuan <zhiyuan.lv@...el.com>,
        Yang Weijiang <weijiang.yang@...el.com>,
        Dapeng Mi <dapeng1.mi@...el.com>,
        Dapeng Mi <dapeng1.mi@...ux.intel.com>
Subject: [PATCH] KVM: x86/pmu: Manipulate FIXED_CTR_CTRL MSR with macros

Magic numbers are used to manipulate the bit fields of
FIXED_CTR_CTRL MSR. This is not read-friendly and use macros to replace
these magic numbers to increase the readability.

Signed-off-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>
---
 arch/x86/include/asm/perf_event.h |  2 ++
 arch/x86/kvm/pmu.c                | 16 +++++++---------
 arch/x86/kvm/pmu.h                | 10 +++++++---
 3 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 85a9fd5a3ec3..018441211af1 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -38,6 +38,8 @@
 #define INTEL_FIXED_0_USER				(1ULL << 1)
 #define INTEL_FIXED_0_ANYTHREAD			(1ULL << 2)
 #define INTEL_FIXED_0_ENABLE_PMI			(1ULL << 3)
+#define INTEL_FIXED_0_ENABLE	\
+	(INTEL_FIXED_0_KERNEL |	INTEL_FIXED_0_USER)
 
 #define HSW_IN_TX					(1ULL << 32)
 #define HSW_IN_TX_CHECKPOINTED				(1ULL << 33)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index edb89b51b383..03fb6b4bca2c 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -418,13 +418,12 @@ static void reprogram_counter(struct kvm_pmc *pmc)
 		printk_once("kvm pmu: pin control bit is ignored\n");
 
 	if (pmc_is_fixed(pmc)) {
-		fixed_ctr_ctrl = fixed_ctrl_field(pmu->fixed_ctr_ctrl,
-						  pmc->idx - INTEL_PMC_IDX_FIXED);
-		if (fixed_ctr_ctrl & 0x1)
+		fixed_ctr_ctrl = pmu_fixed_ctrl_field(pmu, pmc->idx);
+		if (fixed_ctr_ctrl & INTEL_FIXED_0_KERNEL)
 			eventsel |= ARCH_PERFMON_EVENTSEL_OS;
-		if (fixed_ctr_ctrl & 0x2)
+		if (fixed_ctr_ctrl & INTEL_FIXED_0_USER)
 			eventsel |= ARCH_PERFMON_EVENTSEL_USR;
-		if (fixed_ctr_ctrl & 0x8)
+		if (fixed_ctr_ctrl & INTEL_FIXED_0_ENABLE_PMI)
 			eventsel |= ARCH_PERFMON_EVENTSEL_INT;
 		new_config = (u64)fixed_ctr_ctrl;
 	}
@@ -747,10 +746,9 @@ static inline bool cpl_is_matched(struct kvm_pmc *pmc)
 		select_os = config & ARCH_PERFMON_EVENTSEL_OS;
 		select_user = config & ARCH_PERFMON_EVENTSEL_USR;
 	} else {
-		config = fixed_ctrl_field(pmc_to_pmu(pmc)->fixed_ctr_ctrl,
-					  pmc->idx - INTEL_PMC_IDX_FIXED);
-		select_os = config & 0x1;
-		select_user = config & 0x2;
+		config = pmu_fixed_ctrl_field(pmc_to_pmu(pmc), pmc->idx);
+		select_os = config & INTEL_FIXED_0_KERNEL;
+		select_user = config & INTEL_FIXED_0_USER;
 	}
 
 	return (static_call(kvm_x86_get_cpl)(pmc->vcpu) == 0) ? select_os : select_user;
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 7d9ba301c090..2d098aa2fcc6 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -12,7 +12,11 @@
 					  MSR_IA32_MISC_ENABLE_BTS_UNAVAIL)
 
 /* retrieve the 4 bits for EN and PMI out of IA32_FIXED_CTR_CTRL */
-#define fixed_ctrl_field(ctrl_reg, idx) (((ctrl_reg) >> ((idx)*4)) & 0xf)
+#define fixed_ctrl_field(ctrl_reg, idx) \
+	(((ctrl_reg) >> ((idx) * INTEL_FIXED_BITS_STRIDE)) & INTEL_FIXED_BITS_MASK)
+
+#define pmu_fixed_ctrl_field(pmu, idx)	\
+	fixed_ctrl_field((pmu)->fixed_ctr_ctrl, (idx) - INTEL_PMC_IDX_FIXED)
 
 #define VMWARE_BACKDOOR_PMC_HOST_TSC		0x10000
 #define VMWARE_BACKDOOR_PMC_REAL_TIME		0x10001
@@ -164,8 +168,8 @@ static inline bool pmc_speculative_in_use(struct kvm_pmc *pmc)
 	struct kvm_pmu *pmu = pmc_to_pmu(pmc);
 
 	if (pmc_is_fixed(pmc))
-		return fixed_ctrl_field(pmu->fixed_ctr_ctrl,
-					pmc->idx - INTEL_PMC_IDX_FIXED) & 0x3;
+		return pmu_fixed_ctrl_field(pmu, pmc->idx) &
+		       INTEL_FIXED_0_ENABLE;
 
 	return pmc->eventsel & ARCH_PERFMON_EVENTSEL_ENABLE;
 }
-- 
2.34.1