i386: Add Intel Processor Trace feature support

Expose Intel Processor Trace feature to guest.

To make Intel PT live migration safe and get same CPUID information
with same CPU model on diffrent host. CPUID[14] is constant in this
patch. Intel PT use EPT is first supported in IceLake, the CPUID[14]
get on this machine as default value. Intel PT would be disabled
if any machine don't support this minial feature list.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
Message-Id: <1520182116-16485-1-git-send-email-luwei.kang@intel.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

3 files changed, 100 insertions, 2 deletions

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 5ea1931b7e..ec1efd3a3c 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -173,7 +173,32 @@
 #define L2_ITLB_4K_ASSOC       4
 #define L2_ITLB_4K_ENTRIES   512
 
-
+/* CPUID Leaf 0x14 constants: */
+#define INTEL_PT_MAX_SUBLEAF     0x1
+/*
+ * bit[00]: IA32_RTIT_CTL.CR3 filter can be set to 1 and IA32_RTIT_CR3_MATCH
+ *          MSR can be accessed;
+ * bit[01]: Support Configurable PSB and Cycle-Accurate Mode;
+ * bit[02]: Support IP Filtering, TraceStop filtering, and preservation
+ *          of Intel PT MSRs across warm reset;
+ * bit[03]: Support MTC timing packet and suppression of COFI-based packets;
+ */
+#define INTEL_PT_MINIMAL_EBX     0xf
+/*
+ * bit[00]: Tracing can be enabled with IA32_RTIT_CTL.ToPA = 1 and
+ *          IA32_RTIT_OUTPUT_BASE and IA32_RTIT_OUTPUT_MASK_PTRS MSRs can be
+ *          accessed;
+ * bit[01]: ToPA tables can hold any number of output entries, up to the
+ *          maximum allowed by the MaskOrTableOffset field of
+ *          IA32_RTIT_OUTPUT_MASK_PTRS;
+ * bit[02]: Support Single-Range Output scheme;
+ */
+#define INTEL_PT_MINIMAL_ECX     0x7
+#define INTEL_PT_ADDR_RANGES_NUM 0x2 /* Number of configurable address ranges */
+#define INTEL_PT_ADDR_RANGES_NUM_MASK 0x3
+#define INTEL_PT_MTC_BITMAP      (0x0249 << 16) /* Support ART(0,3,6,9) */
+#define INTEL_PT_CYCLE_BITMAP    0x1fff         /* Support 0,2^(0~11) */
+#define INTEL_PT_PSB_BITMAP      (0x003f << 16) /* Support 2K,4K,8K,16K,32K,64K */
 
 static void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
                                      uint32_t vendor2, uint32_t vendor3)
@@ -442,7 +467,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             NULL, NULL, "mpx", NULL,
             "avx512f", "avx512dq", "rdseed", "adx",
             "smap", "avx512ifma", "pcommit", "clflushopt",
-            "clwb", NULL, "avx512pf", "avx512er",
+            "clwb", "intel-pt", "avx512pf", "avx512er",
             "avx512cd", "sha-ni", "avx512bw", "avx512vl",
         },
         .cpuid_eax = 7,
@@ -3467,6 +3492,27 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         }
         break;
     }
+    case 0x14: {
+        /* Intel Processor Trace Enumeration */
+        *eax = 0;
+        *ebx = 0;
+        *ecx = 0;
+        *edx = 0;
+        if (!(env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_INTEL_PT) ||
+            !kvm_enabled()) {
+            break;
+        }
+
+        if (count == 0) {
+            *eax = INTEL_PT_MAX_SUBLEAF;
+            *ebx = INTEL_PT_MINIMAL_EBX;
+            *ecx = INTEL_PT_MINIMAL_ECX;
+        } else if (count == 1) {
+            *eax = INTEL_PT_MTC_BITMAP | INTEL_PT_ADDR_RANGES_NUM;
+            *ebx = INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP;
+        }
+        break;
+    }
     case 0x40000000:
         /*
          * CPUID code in kvm_arch_init_vcpu() ignores stuff
@@ -4097,6 +4143,34 @@ static int x86_cpu_filter_features(X86CPU *cpu)
         }
     }
 
+    if ((env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_INTEL_PT) &&
+        kvm_enabled()) {
+        KVMState *s = CPU(cpu)->kvm_state;
+        uint32_t eax_0 = kvm_arch_get_supported_cpuid(s, 0x14, 0, R_EAX);
+        uint32_t ebx_0 = kvm_arch_get_supported_cpuid(s, 0x14, 0, R_EBX);
+        uint32_t ecx_0 = kvm_arch_get_supported_cpuid(s, 0x14, 0, R_ECX);
+        uint32_t eax_1 = kvm_arch_get_supported_cpuid(s, 0x14, 1, R_EAX);
+        uint32_t ebx_1 = kvm_arch_get_supported_cpuid(s, 0x14, 1, R_EBX);
+
+        if (!eax_0 ||
+           ((ebx_0 & INTEL_PT_MINIMAL_EBX) != INTEL_PT_MINIMAL_EBX) ||
+           ((ecx_0 & INTEL_PT_MINIMAL_ECX) != INTEL_PT_MINIMAL_ECX) ||
+           ((eax_1 & INTEL_PT_MTC_BITMAP) != INTEL_PT_MTC_BITMAP) ||
+           ((eax_1 & INTEL_PT_ADDR_RANGES_NUM_MASK) <
+                                           INTEL_PT_ADDR_RANGES_NUM) ||
+           ((ebx_1 & (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP)) !=
+                (INTEL_PT_PSB_BITMAP | INTEL_PT_CYCLE_BITMAP))) {
+            /*
+             * Processor Trace capabilities aren't configurable, so if the
+             * host can't emulate the capabilities we report on
+             * cpu_x86_cpuid(), intel-pt can't be enabled on the current host.
+             */
+            env->features[FEAT_7_0_EBX] &= ~CPUID_7_0_EBX_INTEL_PT;
+            cpu->filtered_features[FEAT_7_0_EBX] |= CPUID_7_0_EBX_INTEL_PT;
+            rv = 1;
+        }
+    }
+
     return rv;
 }
 
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 8d977ec567..ec2a771299 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -641,6 +641,7 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 #define CPUID_7_0_EBX_PCOMMIT  (1U << 22) /* Persistent Commit */
 #define CPUID_7_0_EBX_CLFLUSHOPT (1U << 23) /* Flush a Cache Line Optimized */
 #define CPUID_7_0_EBX_CLWB     (1U << 24) /* Cache Line Write Back */
+#define CPUID_7_0_EBX_INTEL_PT (1U << 25) /* Intel Processor Trace */
 #define CPUID_7_0_EBX_AVX512PF (1U << 26) /* AVX-512 Prefetch */
 #define CPUID_7_0_EBX_AVX512ER (1U << 27) /* AVX-512 Exponential and Reciprocal */
 #define CPUID_7_0_EBX_AVX512CD (1U << 28) /* AVX-512 Conflict Detection */
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index 44ee524188..f5d3d73ed6 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -869,6 +869,29 @@ int kvm_arch_init_vcpu(CPUState *cs)
                 c = &cpuid_data.entries[cpuid_i++];
             }
             break;
+        case 0x14: {
+            uint32_t times;
+
+            c->function = i;
+            c->index = 0;
+            c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
+            cpu_x86_cpuid(env, i, 0, &c->eax, &c->ebx, &c->ecx, &c->edx);
+            times = c->eax;
+
+            for (j = 1; j <= times; ++j) {
+                if (cpuid_i == KVM_MAX_CPUID_ENTRIES) {
+                    fprintf(stderr, "cpuid_data is full, no space for "
+                                "cpuid(eax:0x14,ecx:0x%x)\n", j);
+                    abort();
+                }
+                c = &cpuid_data.entries[cpuid_i++];
+                c->function = i;
+                c->index = j;
+                c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
+                cpu_x86_cpuid(env, i, j, &c->eax, &c->ebx, &c->ecx, &c->edx);
+            }
+            break;
+        }
         default:
             c->function = i;
             c->flags = 0;