[PATCH 8/8] target/i386: Support Arch LBR in CPUID enumeration

[Yang Weijiang <weijiang.yang@xxxxxxxxx>]

If CPUID.(EAX=07H, ECX=0):EDX[19] is set to 1, the processor
supports Architectural LBRs. In this case, CPUID leaf 01CH
indicates details of the Architectural LBRs capabilities.
XSAVE support for Architectural LBRs is enumerated in
CPUID.(EAX=0DH, ECX=0FH).

Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
---
 target/i386/cpu.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index e505c926b2..1092618683 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -858,7 +858,7 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             "fsrm", NULL, NULL, NULL,
             "avx512-vp2intersect", NULL, "md-clear", NULL,
             NULL, NULL, "serialize", NULL,
-            "tsx-ldtrk", NULL, NULL /* pconfig */, NULL,
+            "tsx-ldtrk", NULL, NULL /* pconfig */, "arch-lbr",
             NULL, NULL, "amx-bf16", "avx512-fp16",
             "amx-tile", "amx-int8", "spec-ctrl", "stibp",
             NULL, "arch-capabilities", "core-capability", "ssbd",
@@ -5494,6 +5494,12 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         assert(!(*eax & ~0x1f));
         *ebx &= 0xffff; /* The count doesn't need to be reliable. */
         break;
+    case 0x1C:
+        *eax = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x1C, 0, R_EAX);
+        *ebx = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x1C, 0, R_EBX);
+        *ecx = kvm_arch_get_supported_cpuid(cs->kvm_state, 0x1C, 0, R_ECX);
+        *edx = 0;
+        break;
     case 0x1F:
         /* V2 Extended Topology Enumeration Leaf */
         if (env->nr_dies < 2) {
@@ -5556,6 +5562,19 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
             *ebx = xsave_area_size(xstate, true);
             *ecx = env->features[FEAT_XSAVE_XSS_LO];
             *edx = env->features[FEAT_XSAVE_XSS_HI];
+            if (kvm_enabled() && cpu->enable_pmu &&
+                (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_ARCH_LBR) &&
+                (*eax & CPUID_XSAVE_XSAVES)) {
+                *ecx |= XSTATE_ARCH_LBR_MASK;
+            } else {
+                *ecx &= ~XSTATE_ARCH_LBR_MASK;
+            }
+        } else if (count == 0xf && kvm_enabled() && cpu->enable_pmu &&
+                   (env->features[FEAT_7_0_EDX] & CPUID_7_0_EDX_ARCH_LBR)) {
+            *eax = kvm_arch_get_supported_cpuid(cs->kvm_state, 0xD, 0xf, R_EAX);
+            *ebx = kvm_arch_get_supported_cpuid(cs->kvm_state, 0xD, 0xf, R_EBX);
+            *ecx = kvm_arch_get_supported_cpuid(cs->kvm_state, 0xD, 0xf, R_ECX);
+            *edx = kvm_arch_get_supported_cpuid(cs->kvm_state, 0xD, 0xf, R_EDX);
         } else if (count < ARRAY_SIZE(x86_ext_save_areas)) {
             const ExtSaveArea *esa = &x86_ext_save_areas[count];
 
-- 
2.27.0