[PATCH v2] KVM: x86/pmu: Manipulate FIXED_CTR_CTRL MSR with macros

From: Dapeng Mi
Date: Mon Aug 14 2023 - 23:43:58 EST


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@xxxxxxxxxxxxxxx>
---
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