[RFC,v2,10/12] i386/cpu: Support Intel hybrid CPUID

Commit Message

Zhao Liu Sept. 19, 2024, 6:11 a.m. UTC

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 | 58 +++++++++++++++++++++++++++++++++++++++++++++++
 target/i386/cpu.h |  5 ++++
 2 files changed, 63 insertions(+)

Patch

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index fb54c2c100a0..2f0e7f3d5ad7 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -22,6 +22,7 @@ 
 #include "qemu/cutils.h"
 #include "qemu/qemu-print.h"
 #include "qemu/hw-version.h"
+#include "core.h"
 #include "cpu.h"
 #include "tcg/helper-tcg.h"
 #include "sysemu/hvf.h"
@@ -743,6 +744,10 @@  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)
 {
@@ -6580,6 +6585,11 @@  void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
                 *ecx |= CPUID_7_0_ECX_OSPKE;
             }
             *edx = env->features[FEAT_7_0_EDX]; /* Feature flags */
+
+            if (env->parent_core_type != COMMON_CORE &&
+                (IS_INTEL_CPU(env) || !cpu->vendor_cpuid_only)) {
+                *edx |= CPUID_7_0_EDX_HYBRID;
+            }
         } else if (count == 1) {
             *eax = env->features[FEAT_7_1_EAX];
             *edx = env->features[FEAT_7_1_EDX];
@@ -6800,6 +6810,31 @@  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->parent_core_type != COMMON_CORE &&
+            (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->parent_core_type) {
+            case INTEL_ATOM:
+                *eax = INTEL_HYBRID_TYPE_ATOM << 24;
+                break;
+            case INTEL_CORE:
+                *eax = INTEL_HYBRID_TYPE_CORE << 24;
+                break;
+            default:
+                g_assert_not_reached();
+            }
+        }
+        break;
     case 0x1D: {
         /* AMX TILE, for now hardcoded for Sapphire Rapids*/
         *eax = 0;
@@ -7459,6 +7494,14 @@  void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
             }
         }
 
+        /*
+         * Intel CPU topology with hybrid cores support requires CPUID.1AH.
+         */
+        if (env->parent_core_type != COMMON_CORE &&
+            (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
@@ -7650,6 +7693,20 @@  static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
         return;
     }
 
+    /*
+     * TODO: Introduce parent_pre_realize to make sure topology device
+     * can realize first.
+     */
+    if (dev->parent_bus && dev->parent_bus->parent) {
+        DeviceState *parent = dev->parent_bus->parent;
+        X86CPUCore *core =
+            (X86CPUCore *)object_dynamic_cast(OBJECT(parent),
+                                              TYPE_X86_CPU_CORE);
+        if (core) {
+            env->parent_core_type = X86_CPU_CORE_GET_CLASS(core)->core_type;
+        }
+    }
+
     /*
      * Process Hyper-V enlightenments.
      * Note: this currently has to happen before the expansion of CPU features.
@@ -8048,6 +8105,7 @@  static void x86_cpu_initfn(Object *obj)
     CPUX86State *env = &cpu->env;
 
     x86_cpu_init_default_topo(cpu);
+    env->parent_core_type = COMMON_CORE;
 
     object_property_add(obj, "feature-words", "X86CPUFeatureWordInfo",
                         x86_cpu_get_feature_words,
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index afe2b5fd3382..38236df547e6 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -21,6 +21,7 @@ 
 #define I386_CPU_H
 
 #include "sysemu/tcg.h"
+#include "core.h"
 #include "cpu-qom.h"
 #include "kvm/hyperv-proto.h"
 #include "exec/cpu-defs.h"
@@ -920,6 +921,8 @@  uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, 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 */
@@ -1996,6 +1999,8 @@  typedef struct CPUArchState {
 
     /* Bitmap of available CPU topology levels for this CPU. */
     DECLARE_BITMAP(avail_cpu_topo, CPU_TOPOLOGY_LEVEL__MAX);
+
+    X86CoreType parent_core_type;
 } CPUX86State;
 
 struct kvm_msrs;