[RFC,39/52] i386/cpu: Add Intel hybrid related CPUID support

Commit Message

Zhao Liu Feb. 13, 2023, 9:50 a.m. UTC

From: Zhao Liu <[e-mail]>

For hybrid cpu topology, Intel exposes these CPUIDs [1]:
1. Set CPUID.07H.0H:EDX.Hybrid[bit 15]. With setting as 1, the processor
   is identified as a hybrid part.
2. Have CPUID.1AH leaf. Set core type and native model ID in
   CPUID.1AH:EAX. Because the native model ID is currently useless for
   the software, no need to emulate.

For hybrid related CPUIDs, especially CPUID.07H.0H:EDX.Hybrid[bit 15],
there's no need to expose this feature in feature_word_info[] to allow
user to set directly, because hybrid features depend on the specific
core type information, and this information needs to be gathered
together with hybrid cpu topology.

[1]: SDM, vol.2, Ch.3, 3.2 Instructions (A-L), CPUID-CPU Identification

Co-Developed-by: Zhuocheng Ding <[e-mail]>
Signed-off-by: Zhuocheng Ding <[e-mail]>
Signed-off-by: Zhao Liu <[e-mail]>
---
 target/i386/cpu.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 target/i386/cpu.h |  2 ++
 2 files changed, 45 insertions(+)

Patch

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 266e981b79e2..a0aaaf996222 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -620,6 +620,10 @@  static CPUCacheInfo legacy_l3_cache = {
 #define INTEL_AMX_TMUL_MAX_K           0x10
 #define INTEL_AMX_TMUL_MAX_N           0x40
 
+/* CPUID Leaf 0x1A constants: */
+#define INTEL_HYBRID_TYPE_ATOM         0x20
+#define INTEL_HYBRID_TYPE_CORE         0x40
+
 void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
                               uint32_t vendor2, uint32_t vendor3)
 {
@@ -5416,6 +5420,11 @@  void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
             }
             *edx = env->features[FEAT_7_0_EDX]; /* Feature flags */
 
+            if (env->hybrid_core_type != INVALID_HYBRID_TYPE &&
+                (IS_INTEL_CPU(env) || !cpu->vendor_cpuid_only)) {
+                *edx |= CPUID_7_0_EDX_HYBRID;
+            }
+
             /*
              * SGX cannot be emulated in software.  If hardware does not
              * support enabling SGX and/or SGX flexible launch control,
@@ -5671,6 +5680,31 @@  void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         }
         break;
     }
+    case 0x1A:
+        /* Hybrid Information Enumeration */
+        *eax = 0;
+        *ebx = 0;
+        *ecx = 0;
+        *edx = 0;
+        if (env->hybrid_core_type != INVALID_HYBRID_TYPE &&
+            (IS_INTEL_CPU(env) || !cpu->vendor_cpuid_only)) {
+            /*
+             * CPUID.1AH:EAX.[bits 23-0] indicates "native model ID of the
+             * core". Since this field currently is useless for software,
+             * no need to emulate.
+             */
+            switch (env->hybrid_core_type) {
+            case INTEL_ATOM_TYPE:
+                *eax = INTEL_HYBRID_TYPE_ATOM << 24;
+                break;
+            case INTEL_CORE_TYPE:
+                *eax = INTEL_HYBRID_TYPE_CORE << 24;
+                break;
+            default:
+                abort();
+            }
+        }
+        break;
     case 0x1D: {
         /* AMX TILE */
         *eax = 0;
@@ -6314,6 +6348,15 @@  void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
             }
         }
 
+        /*
+         * Intel CPU topology with hybrid cores support requires CPUID.1AH.
+         * And CPUID.07H.0H:EDX.Hybrid[bit 15] is also required.
+         */
+        if (env->hybrid_core_type != INVALID_HYBRID_TYPE &&
+            (IS_INTEL_CPU(env) || !cpu->vendor_cpuid_only)) {
+            x86_cpu_adjust_level(cpu, &env->cpuid_min_level, 0x1A);
+        }
+
         /*
          * Intel CPU topology with multi-dies support requires CPUID[0x1F].
          * For AMD Rome/Milan, cpuid level is 0x10, and guest OS should detect
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index bb4e370f9768..8fd7b0c55ae8 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -877,6 +877,8 @@  uint64_t x86_cpu_get_supported_feature_word(FeatureWord w,
 #define CPUID_7_0_EDX_AVX512_VP2INTERSECT (1U << 8)
 /* SERIALIZE instruction */
 #define CPUID_7_0_EDX_SERIALIZE         (1U << 14)
+/* Hybrid */
+#define CPUID_7_0_EDX_HYBRID            (1U << 15)
 /* TSX Suspend Load Address Tracking instruction */
 #define CPUID_7_0_EDX_TSX_LDTRK         (1U << 16)
 /* Architectural LBRs */