[PATCH V5 03/10] KVM: x86/pmu: Make part of the Intel v2 PMU MSRs handling x86 generic

From: Like Xu
Date: Mon Apr 10 2023 - 06:51:36 EST


From: Like Xu <likexu@xxxxxxxxxxx>

AMD PerfMonV2 defines three registers similar to part of the Intel
v2 PMU registers, including the GLOBAL_CTRL, GLOBAL_STATUS and
GLOBAL_OVF_CTRL MSRs. For better code reuse, this specific part of
the handling can be extracted to make it generic for X86 as a straight
code movement.

Specifically, the kvm_pmu_set/get_msr() handlers of GLOBAL_STATUS,
GLOBAL_CTRL, GLOBAL_OVF_CTRL defined for Intel are moved to generic
pmu.c and the callback function .pmc_is_globally_enabled is removed,
which is very helpful to introduce the AMD PerfMonV2 code later.

The new eponymous pmc_is_globally_enabled() works well as legacy AMD
vPMU version is indexed as 1. Note that the specific *_is_valid_msr will
continue to be used to avoid cross-vendor MSR access.

Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
---
arch/x86/include/asm/kvm-x86-pmu-ops.h | 1 -
arch/x86/kvm/pmu.c | 61 ++++++++++++++++++++++----
arch/x86/kvm/pmu.h | 17 ++++++-
arch/x86/kvm/svm/pmu.c | 9 ----
arch/x86/kvm/vmx/pmu_intel.c | 14 +-----
5 files changed, 70 insertions(+), 32 deletions(-)

diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h
index c17e3e96fc1d..6c98f4bb4228 100644
--- a/arch/x86/include/asm/kvm-x86-pmu-ops.h
+++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h
@@ -13,7 +13,6 @@ BUILD_BUG_ON(1)
* at the call sites.
*/
KVM_X86_PMU_OP(hw_event_available)
-KVM_X86_PMU_OP(pmc_is_enabled)
KVM_X86_PMU_OP(pmc_idx_to_pmc)
KVM_X86_PMU_OP(rdpmc_ecx_to_pmc)
KVM_X86_PMU_OP(msr_idx_to_pmc)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 597a8f8f90b9..69d0a3ae7b45 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -93,11 +93,6 @@ void kvm_pmu_ops_update(const struct kvm_pmu_ops *pmu_ops)
#undef __KVM_X86_PMU_OP
}

-static inline bool pmc_is_globally_enabled(struct kvm_pmc *pmc)
-{
- return static_call(kvm_x86_pmu_pmc_is_enabled)(pmc);
-}
-
static void kvm_pmi_trigger_fn(struct irq_work *irq_work)
{
struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu, irq_work);
@@ -577,13 +572,63 @@ static void kvm_pmu_mark_pmc_in_use(struct kvm_vcpu *vcpu, u32 msr)

int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
- return static_call(kvm_x86_pmu_get_msr)(vcpu, msr_info);
+ struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+ u32 msr = msr_info->index;
+
+ switch (msr) {
+ case MSR_CORE_PERF_GLOBAL_STATUS:
+ msr_info->data = pmu->global_status;
+ break;
+ case MSR_CORE_PERF_GLOBAL_CTRL:
+ msr_info->data = pmu->global_ctrl;
+ break;
+ case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
+ msr_info->data = 0;
+ break;
+ default:
+ return static_call(kvm_x86_pmu_get_msr)(vcpu, msr_info);
+ }
+
+ return 0;
}

int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
- kvm_pmu_mark_pmc_in_use(vcpu, msr_info->index);
- return static_call(kvm_x86_pmu_set_msr)(vcpu, msr_info);
+ struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+ u32 msr = msr_info->index;
+ u64 data = msr_info->data;
+ u64 diff;
+
+ switch (msr) {
+ case MSR_CORE_PERF_GLOBAL_STATUS:
+ if (!msr_info->host_initiated || (data & pmu->global_ovf_ctrl_mask))
+ return 1; /* RO MSR */
+
+ pmu->global_status = data;
+ break;
+ case MSR_CORE_PERF_GLOBAL_CTRL:
+ if (!kvm_valid_perf_global_ctrl(pmu, data))
+ return 1;
+
+ if (pmu->global_ctrl != data) {
+ diff = pmu->global_ctrl ^ data;
+ pmu->global_ctrl = data;
+ reprogram_counters(pmu, diff);
+ }
+ break;
+ case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
+ if (data & pmu->global_ovf_ctrl_mask)
+ return 1;
+
+ if (!msr_info->host_initiated)
+ pmu->global_status &= ~data;
+ break;
+ default:
+ kvm_pmu_mark_pmc_in_use(vcpu, msr_info->index);
+ return static_call(kvm_x86_pmu_set_msr)(vcpu, msr_info);
+ }
+
+ return 0;
}

/* refresh PMU settings. This function generally is called when underlying
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 986563aeeef8..dd7c7d4ffe3b 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -20,7 +20,6 @@

struct kvm_pmu_ops {
bool (*hw_event_available)(struct kvm_pmc *pmc);
- 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,
unsigned int idx, u64 *mask);
@@ -213,6 +212,22 @@ static inline void reprogram_counters(struct kvm_pmu *pmu, u64 diff)
kvm_make_request(KVM_REQ_PMU, pmu_to_vcpu(pmu));
}

+/*
+ * Check if a PMC is enabled by comparing it against global_ctrl bits.
+ *
+ * If the current version of vPMU doesn't have global_ctrl MSR,
+ * all vPMCs are enabled (return TRUE).
+ */
+static inline bool pmc_is_globally_enabled(struct kvm_pmc *pmc)
+{
+ struct kvm_pmu *pmu = pmc_to_pmu(pmc);
+
+ if (pmu->version < 2)
+ return true;
+
+ return test_bit(pmc->idx, (unsigned long *)&pmu->global_ctrl);
+}
+
void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu);
void kvm_pmu_handle_event(struct kvm_vcpu *vcpu);
int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data);
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 5fa939e411d8..70143275e0a7 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -78,14 +78,6 @@ static bool amd_hw_event_available(struct kvm_pmc *pmc)
return true;
}

-/* 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).
- */
-static bool amd_pmc_is_enabled(struct kvm_pmc *pmc)
-{
- return true;
-}
-
static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -220,7 +212,6 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)

struct kvm_pmu_ops amd_pmu_ops __initdata = {
.hw_event_available = amd_hw_event_available,
- .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,
.msr_idx_to_pmc = amd_msr_idx_to_pmc,
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 343b3182b7f4..99d07ccb1869 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -95,17 +95,6 @@ static bool intel_hw_event_available(struct kvm_pmc *pmc)
return true;
}

-/* check if a PMC is enabled by comparing it with globl_ctrl bits. */
-static bool intel_pmc_is_enabled(struct kvm_pmc *pmc)
-{
- struct kvm_pmu *pmu = pmc_to_pmu(pmc);
-
- if (!intel_pmu_has_perf_global_ctrl(pmu))
- return true;
-
- return test_bit(pmc->idx, (unsigned long *)&pmu->global_ctrl);
-}
-
static bool intel_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -793,7 +782,7 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu)
pmc = intel_pmc_idx_to_pmc(pmu, bit);

if (!pmc || !pmc_speculative_in_use(pmc) ||
- !intel_pmc_is_enabled(pmc) || !pmc->perf_event)
+ !pmc_is_globally_enabled(pmc) || !pmc->perf_event)
continue;

/*
@@ -808,7 +797,6 @@ void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu)

struct kvm_pmu_ops intel_pmu_ops __initdata = {
.hw_event_available = intel_hw_event_available,
- .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,
.msr_idx_to_pmc = intel_msr_idx_to_pmc,
--
2.40.0