KVM: Expose the architectural performance monitoring CPUID leaf

Provide a CPUID leaf that describes the emulated PMU.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 29 insertions, 1 deletions

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index e70be46f50fc..89b02bfaaca5 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -327,6 +327,35 @@ static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
         }
         case 9:
                 break;
+        case 0xa: { /* Architectural Performance Monitoring */
+                struct x86_pmu_capability cap;
+                union cpuid10_eax eax;
+                union cpuid10_edx edx;
+
+                perf_get_x86_pmu_capability(&cap);
+
+                /*
+                 * Only support guest architectural pmu on a host
+                 * with architectural pmu.
+                 */
+                if (!cap.version)
+                        memset(&cap, 0, sizeof(cap));
+
+                eax.split.version_id = min(cap.version, 2);
+                eax.split.num_counters = cap.num_counters_gp;
+                eax.split.bit_width = cap.bit_width_gp;
+                eax.split.mask_length = cap.events_mask_len;
+
+                edx.split.num_counters_fixed = cap.num_counters_fixed;
+                edx.split.bit_width_fixed = cap.bit_width_fixed;
+                edx.split.reserved = 0;
+
+                entry->eax = eax.full;
+                entry->ebx = cap.events_mask;
+                entry->ecx = 0;
+                entry->edx = edx.full;
+                break;
+        }
         /* function 0xb has additional index. */
         case 0xb: {
                 int i, level_type;
@@ -427,7 +456,6 @@ static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
         case 3: /* Processor serial number */
         case 5: /* MONITOR/MWAIT */
         case 6: /* Thermal management */
-        case 0xA: /* Architectural Performance Monitoring */
         case 0x80000007: /* Advanced power management */
         case 0xC0000002:
         case 0xC0000003: