Move the handling of "fast" RDPMC instructions, which drop bits 63:32 of
the count, to Intel. The "fast" flag, and all modifiers for that matter,
are Intel-only and aren't supported by AMD.
Opportunistically replace open coded bit crud with proper #defines, and
add comments to try and disentangle the flags vs. values mess for
non-architectural vs. architectural PMUs.
Fixes: ca724305a2b0 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM")
Reviewed-by: Dapeng Mi <dapeng1.mi@xxxxxxxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/pmu.c | 3 +--
arch/x86/kvm/vmx/pmu_intel.c | 16 ++++++++++++++--
2 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 0b0d804ee239..09b0feb975c3 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -576,10 +576,9 @@ static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
{
- bool fast_mode = idx & (1u << 31);
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
struct kvm_pmc *pmc;
- u64 mask = fast_mode ? ~0u : ~0ull;
+ u64 mask = ~0ull;
if (!pmu->version)
return 1;
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 1b1f888ad32b..03bd188b5754 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -20,6 +20,15 @@
#include "nested.h"
#include "pmu.h"
+/*
+ * Perf's "BASE" is wildly misleading, architectural PMUs use bits 31:16 of ECX
+ * to encode the "type" of counter to read, i.e. this is not a "base". And to
+ * further confuse things, non-architectural PMUs use bit 31 as a flag for
+ * "fast" reads, whereas the "type" is an explicit value.
+ */
+#define INTEL_RDPMC_FIXED INTEL_PMC_FIXED_RDPMC_BASE
+#define INTEL_RDPMC_FAST BIT(31)
+
#define MSR_PMC_FULL_WIDTH_BIT (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0)
static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data)
@@ -59,11 +68,14 @@ static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu,
unsigned int idx, u64 *mask)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
- bool fixed = idx & (1u << 30);
+ bool fixed = idx & INTEL_RDPMC_FIXED;
struct kvm_pmc *counters;
unsigned int num_counters;
- idx &= ~(3u << 30);
+ if (idx & INTEL_RDPMC_FAST)
+ *mask &= GENMASK_ULL(31, 0);
+
+ idx &= ~(INTEL_RDPMC_FIXED | INTEL_RDPMC_FAST);
if (fixed) {
counters = pmu->fixed_counters;
num_counters = pmu->nr_arch_fixed_counters;
--
2.43.0.472.g3155946c3a-goog
