--- sys/amd64/amd64/identcpu.c	29 Apr 2009 06:54:40 -0000	1.172
+++ sys/amd64/amd64/identcpu.c	1 May 2009 20:00:59 -0000
@@ -472,6 +472,24 @@
 	cpu_feature = regs[3];
 	cpu_feature2 = regs[2];
 
+	/*
+	 * Clear "Limit CPUID Maxval" bit and get the highest
+	 * basic CPUID function again if it is set from BIOS.
+	 * It is necessary for probing correct CPU topology later.
+	 * XXX This is only done on BSP.
+	 */
+	if (cpu_vendor_id == CPU_VENDOR_INTEL &&
+	    cpu_high > 0 && cpu_high < 4 &&
+	    (cpu_feature & CPUID_HTT) != 0) {
+		uint64_t msr;
+		msr = rdmsr(MSR_IA32_MISC_ENABLE);
+		if ((msr & 0x400000ULL) != 0) {
+			wrmsr(MSR_IA32_MISC_ENABLE, msr & ~0x400000ULL);
+			do_cpuid(0, regs);
+			cpu_high = regs[0];
+		}
+	}
+
 	if (cpu_vendor_id == CPU_VENDOR_INTEL ||
 	    cpu_vendor_id == CPU_VENDOR_AMD ||
 	    cpu_vendor_id == CPU_VENDOR_CENTAUR) {
--- sys/i386/i386/identcpu.c	29 Apr 2009 06:54:40 -0000	1.201
+++ sys/i386/i386/identcpu.c	1 May 2009 20:00:59 -0000
@@ -323,15 +323,6 @@
 				strcat(cpu_model, "Pentium 4");
 				cpu = CPU_P4;
 				model = (cpu_id & 0x0f0) >> 4;
-				if (model == 3 || model == 4 || model == 6) {
-					uint64_t tmp;
-
-					tmp = rdmsr(MSR_IA32_MISC_ENABLE);
-					wrmsr(MSR_IA32_MISC_ENABLE,
-					      tmp & ~(1LL << 22));
-					do_cpuid(0, regs);
-					cpu_high = regs[0];
-				}
 				break;
 			default:
 				strcat(cpu_model, "unknown");
@@ -1110,6 +1101,24 @@
 
 	cpu_vendor_id = find_cpu_vendor_id();
 
+	/*
+	 * Clear "Limit CPUID Maxval" bit and get the highest
+	 * basic CPUID function again if it is set from BIOS.
+	 * It is necessary for probing correct CPU topology later.
+	 * XXX This is only done on BSP.
+	 */
+	if (cpu_vendor_id == CPU_VENDOR_INTEL &&
+	    cpu_high > 0 && cpu_high < 4 &&
+	    (cpu_feature & CPUID_HTT) != 0) {
+		uint64_t msr;
+		msr = rdmsr(MSR_IA32_MISC_ENABLE);
+		if ((msr & 0x400000ULL) != 0) {
+			wrmsr(MSR_IA32_MISC_ENABLE, msr & ~0x400000ULL);
+			do_cpuid(0, regs);
+			cpu_high = regs[0];
+		}
+	}
+
 	/* Detect AMD features (PTE no-execute bit, 3dnow, 64 bit mode etc) */
 	if (cpu_vendor_id == CPU_VENDOR_INTEL ||
 	    cpu_vendor_id == CPU_VENDOR_AMD) {