i386/cpu: Support APX CPUIDs

APX is enumerated by CPUID.(EAX=0x7, ECX=1).EDX[21]. And this feature
bit also indicates the existence of dedicated CPUID leaf 0x29, called
the Intel APX Advanced Performance Extensions Leaf.

This new CPUID leaf now is populated with enumerations for a select
set of Intel APX sub-features.

CPUID.(EAX=0x29, ECX=0)
 - EAX
   * Maximum Subleaf CPUID.(EAX=0x29, ECX=0).EAX[31:0] = 0
 - EBX
   * Reserved CPUID.(EAX=0x29, ECX=0).EBX[31:1] = 0
   * APX_NCI_NDD_NF CPUID.(EAX=0x29, ECX=0).EBX[0:0] = 1, which
     enumerates the presence of New Conditional Instructions (NCIs),
     explicit New Data Destination (NDD) controls, and explicit Flags
     Suppression (NF) controls for select sets of EVEX-encoded Intel
     APX instructions (present in EVEX map=4, and EVEX map=2 0x0F38).
 - ECX
   * Reserved CPUID.(EAX=0x29, ECX=0).ECX[31:0] = 0
 - EDX
   * Reserved CPUID.(EAX=0x29, ECX=0).EDX[31:0] = 0

Note, APX_NCI_NDD_NF is documented as always enabled for Intel
processors since APX spec (revision v7.0). Now any Intel processor
that enumerates support for APX_F (CPUID.(EAX=0x7, ECX=1).EDX[21])
will also enumerate support for APX_NCI_NDD_NF.

Tested-by: Xudong Hao <xudong.hao@intel.com>
Co-developed-by: Zide Chen <zide.chen@intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
Co-developed-by: Peter Fang <peter.fang@intel.com>
Signed-off-by: Peter Fang <peter.fang@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20251211070942.3612547-9-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 3c9ed7cd5f7b771745e3d7ac8170afb6a3b1e6ff..c9efd3a9d4630821e3bcd7393e417e105ab45b99 100644 (file)
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1036,6 +1036,7 @@ void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
 #define TCG_SGX_12_0_EBX_FEATURES 0
 #define TCG_SGX_12_1_EAX_FEATURES 0
 #define TCG_24_0_EBX_FEATURES 0
+#define TCG_29_0_EBX_FEATURES 0
 
 #if defined CONFIG_USER_ONLY
 #define CPUID_8000_0008_EBX_KERNEL_FEATURES (CPUID_8000_0008_EBX_IBPB | \
@@ -1301,7 +1302,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             "amx-complex", NULL, "avx-vnni-int16", NULL,
             NULL, NULL, "prefetchiti", NULL,
             NULL, NULL, NULL, "avx10",
-            NULL, NULL, NULL, NULL,
+            NULL, "apxf", NULL, NULL,
             NULL, NULL, NULL, NULL,
             NULL, NULL, NULL, NULL,
         },
@@ -1345,6 +1346,25 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         },
         .tcg_features = TCG_24_0_EBX_FEATURES,
     },
+    [FEAT_29_0_EBX] = {
+        .type = CPUID_FEATURE_WORD,
+        .feat_names = {
+            "apx-nci-ndd-nf", NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL, NULL,
+        },
+        .cpuid = {
+            .eax = 0x29,
+            .needs_ecx = true, .ecx = 0,
+            .reg = R_EBX,
+        },
+        .tcg_features = TCG_29_0_EBX_FEATURES,
+    },
     [FEAT_8000_0007_EDX] = {
         .type = CPUID_FEATURE_WORD,
         .feat_names = {
@@ -1996,6 +2016,10 @@ static FeatureDep feature_dependencies[] = {
         .from = { FEAT_7_1_EDX,             CPUID_7_1_EDX_AVX10 },
         .to = { FEAT_24_0_EBX,              ~0ull },
     },
+    {
+        .from = { FEAT_7_1_EDX,             CPUID_7_1_EDX_APXF },
+        .to = { FEAT_29_0_EBX,              ~0ull },
+    },
 };
 
 typedef struct X86RegisterInfo32 {
@@ -8411,6 +8435,15 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         }
         break;
     }
+    case 0x29:
+        *eax = 0;
+        *ebx = 0;
+        *ecx = 0;
+        *edx = 0;
+        if ((env->features[FEAT_7_1_EDX] & CPUID_7_1_EDX_APXF) && count == 0) {
+            *ebx = env->features[FEAT_29_0_EBX];
+        }
+        break;
     case 0x40000000:
         /*
          * CPUID code in kvm_arch_init_vcpu() ignores stuff
@@ -9190,6 +9223,11 @@ void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
             x86_cpu_adjust_level(cpu, &env->cpuid_min_level, 0x24);
         }
 
+        /* Advanced Performance Extensions (APX) requires CPUID[0x29] */
+        if (env->features[FEAT_7_1_EDX] & CPUID_7_1_EDX_APXF) {
+            x86_cpu_adjust_level(cpu, &env->cpuid_min_level, 0x29);
+        }
+
         /* SVM requires CPUID[0x8000000A] */
         if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_SVM) {
             x86_cpu_adjust_level(cpu, &env->cpuid_min_xlevel, 0x8000000A);

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 691ed97468417c29e795f5aaa487bf6a1cac717b..fc6348836490a44f4085a97f89d220f9dc26aafd 100644 (file)
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -710,6 +710,7 @@ typedef enum FeatureWord {
     FEAT_7_1_EDX,       /* CPUID[EAX=7,ECX=1].EDX */
     FEAT_7_2_EDX,       /* CPUID[EAX=7,ECX=2].EDX */
     FEAT_24_0_EBX,      /* CPUID[EAX=0x24,ECX=0].EBX */
+    FEAT_29_0_EBX,      /* CPUID[EAX=0x29,ECX=0].EBX */
     FEATURE_WORDS,
 } FeatureWord;
 
@@ -1092,6 +1093,13 @@ uint64_t x86_cpu_get_supported_feature_word(X86CPU *cpu, FeatureWord w);
                                          CPUID_24_0_EBX_AVX10_256 | \
                                          CPUID_24_0_EBX_AVX10_512)
 
+/*
+ * New Conditional Instructions (NCIs), explicit New Data Destination (NDD)
+ * controls, and explicit Flags Suppression (NF) controls for select sets of
+ * EVEX-encoded Intel APX instructions
+ */
+#define CPUID_29_0_EBX_APX_NCI_NDD_NF         (1U << 0)
+
 /* RAS Features */
 #define CPUID_8000_0007_EBX_OVERFLOW_RECOV    (1U << 0)
 #define CPUID_8000_0007_EBX_SUCCOR      (1U << 1)