[Qemu-devel] [PATCH 2/2] target/i386: Add support for put/get PEBS registers

[Luwei Kang]

This patch add a new feature words for IA32_PERF_CAPABILITIES (RO)
register that serve to expose PEBS output Intel PT feature.
The registers relate with PEBS need to be set/get when PEBS output
Intel PT is supported in guest.

Signed-off-by: Luwei Kang <address@hidden>
---
 target/i386/cpu.c | 20 ++++++++++++++++++++
 target/i386/cpu.h |  4 ++++
 target/i386/kvm.c | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 9e0bac3..7fe34c0 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1244,6 +1244,26 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] 
= {
             },
         },
     },
+    [FEAT_PERF_CAPABILITIES] = {
+        .type = MSR_FEATURE_WORD,
+        .feat_names = {
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            "pebs-output-pt", NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+        },
+        .msr = {
+            .index = MSR_IA32_PERF_CAPABILITIES,
+            .cpuid_dep = {
+                FEAT_1_ECX,
+                CPUID_EXT_PDCM,
+            },
+        },
+    },
 };
 
 typedef struct X86RegisterInfo32 {
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index d7cec36..0904004 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -347,6 +347,7 @@ typedef enum X86Seg {
 #define MSR_IA32_PRED_CMD               0x49
 #define MSR_IA32_CORE_CAPABILITY        0xcf
 #define MSR_IA32_ARCH_CAPABILITIES      0x10a
+#define MSR_IA32_PERF_CAPABILITIES      0x345
 #define MSR_IA32_TSCDEADLINE            0x6e0
 
 #define FEATURE_CONTROL_LOCKED                    (1<<0)
@@ -503,6 +504,7 @@ typedef enum FeatureWord {
     FEAT_XSAVE_COMP_HI, /* CPUID[EAX=0xd,ECX=0].EDX */
     FEAT_ARCH_CAPABILITIES,
     FEAT_CORE_CAPABILITY,
+    FEAT_PERF_CAPABILITIES,
     FEATURE_WORDS,
 } FeatureWord;
 
@@ -754,6 +756,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 
 #define MSR_CORE_CAP_SPLIT_LOCK_DETECT  (1U << 5)
 
+#define MSR_PERF_CAP_PEBS_VIA_PT        (1ULL << 16)
+
 /* Supported Hyper-V Enlightenments */
 #define HYPERV_FEAT_RELAXED             0
 #define HYPERV_FEAT_VAPIC               1
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 8023c67..c0dcc13 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -2651,6 +2651,20 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
                 kvm_msr_entry_add(cpu, MSR_IA32_RTIT_ADDR0_A + i,
                             env->msr_rtit_addrs[i]);
             }
+
+            if (env->features[FEAT_PERF_CAPABILITIES] &
+                                        MSR_PERF_CAP_PEBS_VIA_PT) {
+                kvm_msr_entry_add(cpu, MSR_IA32_PEBS_ENABLE,
+                                env->msr_pebs_enable);
+                for (i = 0; i < num_architectural_pmu_fixed_counters; i++) {
+                    kvm_msr_entry_add(cpu, MSR_RELOAD_FIXED_CTR0 + i,
+                                env->msr_reload_fixed_ctr[i]);
+                }
+                for (i = 0; i < num_architectural_pmu_gp_counters; i++) {
+                    kvm_msr_entry_add(cpu, MSR_RELOAD_PMC0 + i,
+                                env->msr_reload_pmc[i]);
+                }
+            }
         }
 
         /* Note: MSR_IA32_FEATURE_CONTROL is written separately, see
@@ -2989,6 +3003,16 @@ static int kvm_get_msrs(X86CPU *cpu)
         for (i = 0; i < addr_num; i++) {
             kvm_msr_entry_add(cpu, MSR_IA32_RTIT_ADDR0_A + i, 0);
         }
+
+        if (env->features[FEAT_PERF_CAPABILITIES] & MSR_PERF_CAP_PEBS_VIA_PT) {
+            kvm_msr_entry_add(cpu, MSR_IA32_PEBS_ENABLE, 0);
+            for (i = 0; i < num_architectural_pmu_fixed_counters; i++) {
+                kvm_msr_entry_add(cpu, MSR_RELOAD_FIXED_CTR0 + i, 0);
+            }
+            for (i = 0; i < num_architectural_pmu_gp_counters; i++) {
+                kvm_msr_entry_add(cpu, MSR_RELOAD_PMC0 + i, 0);
+            }
+        }
     }
 
     ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, cpu->kvm_msr_buf);
@@ -3268,6 +3292,18 @@ static int kvm_get_msrs(X86CPU *cpu)
         case MSR_IA32_RTIT_ADDR0_A ... MSR_IA32_RTIT_ADDR3_B:
             env->msr_rtit_addrs[index - MSR_IA32_RTIT_ADDR0_A] = msrs[i].data;
             break;
+        case MSR_IA32_PEBS_ENABLE:
+            env->msr_pebs_enable = msrs[i].data;
+            break;
+        case MSR_RELOAD_FIXED_CTR0 ...
+                                MSR_RELOAD_FIXED_CTR0 + MAX_FIXED_COUNTERS - 1:
+            env->msr_reload_fixed_ctr[index - MSR_RELOAD_FIXED_CTR0] =
+                                                                msrs[i].data;
+            break;
+        case MSR_RELOAD_PMC0 ...
+                                MSR_RELOAD_PMC0 + MAX_GP_COUNTERS - 1:
+            env->msr_reload_fixed_ctr[index - MSR_RELOAD_PMC0] = msrs[i].data;
+            break;
         }
     }
 
-- 
1.8.3.1