linux-kernel - [PATCH v2] KVM: x86/pmu: Manipulate FIXED_CTR

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Date:   Tue, 15 Aug 2023 11:28:49 +0800
From:   Dapeng Mi <dapeng1.mi@...ux.intel.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Like Xu <likexu@...cent.com>
Cc:     kvm@...r.kernel.org, linux-perf-users@...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>,
        Dapeng Mi <dapeng1.mi@...el.com>,
        Dapeng Mi <dapeng1.mi@...ux.intel.com>
Subject: [PATCH v2] 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/kvm/pmu.c | 10 +++++-----
 arch/x86/kvm/pmu.h |  6 ++++--
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index edb89b51b383..fb4ef2da3e32 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -420,11 +420,11 @@ static void reprogram_counter(struct kvm_pmc *pmc)
 	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)
+		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;
 	}
@@ -749,8 +749,8 @@ static inline bool cpl_is_matched(struct kvm_pmc *pmc)
 	} 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;
+		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..ffda2ecc3a22 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -12,7 +12,8 @@
 					  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 VMWARE_BACKDOOR_PMC_HOST_TSC		0x10000
 #define VMWARE_BACKDOOR_PMC_REAL_TIME		0x10001
@@ -165,7 +166,8 @@ static inline bool pmc_speculative_in_use(struct kvm_pmc *pmc)
 
 	if (pmc_is_fixed(pmc))
 		return fixed_ctrl_field(pmu->fixed_ctr_ctrl,
-					pmc->idx - INTEL_PMC_IDX_FIXED) & 0x3;
+					pmc->idx - INTEL_PMC_IDX_FIXED) &
+					(INTEL_FIXED_0_KERNEL | INTEL_FIXED_0_USER);
 
 	return pmc->eventsel & ARCH_PERFMON_EVENTSEL_ENABLE;
 }

base-commit: 240f736891887939571854bd6d734b6c9291f22e
-- 
2.34.1