i386: Implement EBL_CR_POWERON MSR for Xbox CPU

Author: thrimbor

target/i386/cpu.h

@@ -378,6 +378,7 @@ typedef enum X86Seg {
 #define MSR_IA32_APICBASE_ENABLE        (1<<11)
 #define MSR_IA32_APICBASE_EXTD          (1 << 10)
 #define MSR_IA32_APICBASE_BASE          (0xfffffU<<12)
+#define MSR_IA32_EBL_CR_POWERON         0x2a
 #define MSR_IA32_FEATURE_CONTROL        0x0000003a
 #define MSR_TSC_ADJUST                  0x0000003b
 #define MSR_IA32_SPEC_CTRL              0x48

target/i386/tcg/sysemu/misc_helper.c

@@ -428,6 +428,11 @@ void helper_rdmsr(CPUX86State *env)
             val = 0;
         }
         break;
+#ifdef XBOX
+    case MSR_IA32_EBL_CR_POWERON:
+        val = 0xc5040000;
+        break;
+#endif
     case MSR_MCG_CAP:
         val = env->mcg_cap;
         break;