diff --git a/src/arch/x86/X86ISA.py b/src/arch/x86/X86ISA.py
index aa5c29a98e..aa48d1aa6e 100644
--- a/src/arch/x86/X86ISA.py
+++ b/src/arch/x86/X86ISA.py
@@ -85,6 +85,20 @@ class X86ISA(BaseISA):
     ExtendedFeatures = VectorParam.UInt32(
         [0x00000000, 0x01800000, 0x00000000, 0x00000000], "feature flags"
     )
+    # 0000_000Dh - This uses ECX index, so the last entry must be all zeros
+    ExtendedState = VectorParam.UInt32(
+        [
+            0x00000000,
+            0x00000000,
+            0x00000000,
+            0x00000000,
+            0x00000000,
+            0x00000000,
+            0x00000000,
+            0x00000000,
+        ],
+        "extended state enumeration",
+    )
     # 8000_0001h
     FamilyModelSteppingBrandFeatures = VectorParam.UInt32(
         [0x00020F51, 0x00000405, 0xEBD3FBFF, 0x00020001],
diff --git a/src/arch/x86/cpuid.cc b/src/arch/x86/cpuid.cc
index 75e69735c1..2ce9ec9289 100644
--- a/src/arch/x86/cpuid.cc
+++ b/src/arch/x86/cpuid.cc
@@ -146,6 +146,18 @@ X86CPUID::stringToRegister(const char *str)
 bool
 X86CPUID::hasSignificantIndex(uint32_t function)
 {
+    uint16_t family = bits(function, 31, 16);
+    uint16_t funcNum = bits(function, 15, 0);
+
+    if (family == 0x0000) {
+        switch (funcNum) {
+          case ExtendedState:
+            return true;
+          default:
+            return false;
+        }
+    }
+
     return false;
 }
 
diff --git a/src/arch/x86/cpuid.hh b/src/arch/x86/cpuid.hh
index 71e8d3c626..1c932980d2 100644
--- a/src/arch/x86/cpuid.hh
+++ b/src/arch/x86/cpuid.hh
@@ -52,6 +52,7 @@ enum StandardCpuidFunction
     MonitorMwait,
     ThermalPowerMgmt,
     ExtendedFeatures,
+    ExtendedState = 0xD,
     NumStandardCpuidFuncs
 };
 
diff --git a/src/arch/x86/isa.cc b/src/arch/x86/isa.cc
index cf1ff9f593..9e6082a268 100644
--- a/src/arch/x86/isa.cc
+++ b/src/arch/x86/isa.cc
@@ -157,6 +157,7 @@ ISA::ISA(const X86ISAParams &p)
     cpuid->addStandardFunc(FamilyModelStepping, p.FamilyModelStepping);
     cpuid->addStandardFunc(CacheParams, p.CacheParams);
     cpuid->addStandardFunc(ExtendedFeatures, p.ExtendedFeatures);
+    cpuid->addStandardFunc(ExtendedState, p.ExtendedState);
 
     cpuid->addExtendedFunc(FamilyModelSteppingBrandFeatures,
                           p.FamilyModelSteppingBrandFeatures);