--- mp_machdep.c.orig	2010-06-22 12:20:10.000000000 -0400
+++ mp_machdep.c	2010-07-15 15:14:13.000000000 -0400
@@ -177,19 +177,76 @@ mem_range_AP_init(void)
 }
 
 static void
-topo_probe_0xb(void)
+topo_probe_amd(void)
+{
+
+	/* AMD processors do not support HTT. */
+	cpu_cores = (amd_feature2 & AMDID2_CMP) != 0 ?
+	    (cpu_procinfo2 & AMDID_CMP_CORES) + 1 : 1;
+	cpu_logical = 1;
+}
+
+static void
+topo_probe_0x4(void)
 {
+	u_int p[4];
+	int cores;
+	int i;
+	int level;
 	int logical;
-	int p[4];
-	int bits;
 	int type;
+
+	cpu_logical = (cpu_feature & CPUID_HTT) != 0 ?
+	    (cpu_procinfo & CPUID_HTT_CORES) >> 16 : 1;
+	if (cpu_logical == 1) {
+		cpu_cores = 1;
+		return;
+	}
+
+	/* We only support three levels for now. */
+	for (i = 0; i < 3; i++) {
+		cpuid_count(0x04, i, p);
+		type = p[0] & 0x1f;
+		level = (p[0] >> 5) & 0x7;
+		logical = ((p[0] >> 14) & 0xfff) + 1;
+		cores = ((p[0] >> 26) & 0x3f) + 1;
+		if (type == 0)
+			break;
+		if (level == 1 && cpu_logical == logical * cores) {
+			cpu_cores = cores;
+			cpu_logical = logical;
+			break;
+		}
+	}
+	if (cpu_cores == 0)
+		cpu_cores = 1;
+	if (cpu_logical > 1)
+		hyperthreading_cpus = logical_cpus = cpu_logical;
+}
+
+static void
+topo_probe_0xb(void)
+{
+	u_int p[4];
+	int bits;
 	int cnt;
 	int i;
+	int logical;
+	int type;
 	int x;
 
-	/* We only support two levels for now. */
+	/* We only support three levels for now. */
 	for (i = 0; i < 3; i++) {
-		cpuid_count(0x0B, i, p);
+		cpuid_count(0x0b, i, p);
+
+		/*
+		 * Fall back if it is not really supported.
+		 */
+		if (i == 0 && p[1] == 0) {
+			topo_probe_0x4();
+			return;
+		}
+
 		bits = p[0] & 0x1f;
 		logical = p[1] &= 0xffff;
 		type = (p[2] >> 8) & 0xff;
@@ -213,76 +270,6 @@ topo_probe_0xb(void)
 }
 
 static void
-topo_probe_0x4(void)
-{
-	u_int threads_per_cache, p[4];
-	u_int htt, cmp;
-	int i;
-
-	htt = cmp = 1;
-	/*
-	 * If this CPU supports HTT or CMP then mention the
-	 * number of physical/logical cores it contains.
-	 */
-	if (cpu_feature & CPUID_HTT)
-		htt = (cpu_procinfo & CPUID_HTT_CORES) >> 16;
-	if (cpu_vendor_id == CPU_VENDOR_AMD && (amd_feature2 & AMDID2_CMP))
-		cmp = (cpu_procinfo2 & AMDID_CMP_CORES) + 1;
-	else if (cpu_vendor_id == CPU_VENDOR_INTEL && (cpu_high >= 4)) {
-		cpuid_count(4, 0, p);
-		if ((p[0] & 0x1f) != 0)
-			cmp = ((p[0] >> 26) & 0x3f) + 1;
-	}
-	cpu_cores = cmp;
-	cpu_logical = htt / cmp;
-
-	/* Setup the initial logical CPUs info. */
-	if (cpu_feature & CPUID_HTT)
-		logical_cpus = (cpu_procinfo & CPUID_HTT_CORES) >> 16;
-
-	/*
-	 * Work out if hyperthreading is *really* enabled.  This
-	 * is made really ugly by the fact that processors lie: Dual
-	 * core processors claim to be hyperthreaded even when they're
-	 * not, presumably because they want to be treated the same
-	 * way as HTT with respect to per-cpu software licensing.
-	 * At the time of writing (May 12, 2005) the only hyperthreaded
-	 * cpus are from Intel, and Intel's dual-core processors can be
-	 * identified via the "deterministic cache parameters" cpuid
-	 * calls.
-	 */
-	/*
-	 * First determine if this is an Intel processor which claims
-	 * to have hyperthreading support.
-	 */
-	if ((cpu_feature & CPUID_HTT) && cpu_vendor_id == CPU_VENDOR_INTEL) {
-		/*
-		 * If the "deterministic cache parameters" cpuid calls
-		 * are available, use them.
-		 */
-		if (cpu_high >= 4) {
-			/* Ask the processor about the L1 cache. */
-			for (i = 0; i < 1; i++) {
-				cpuid_count(4, i, p);
-				threads_per_cache = ((p[0] & 0x3ffc000) >> 14) + 1;
-				if (hyperthreading_cpus < threads_per_cache)
-					hyperthreading_cpus = threads_per_cache;
-				if ((p[0] & 0x1f) == 0)
-					break;
-			}
-		}
-
-		/*
-		 * If the deterministic cache parameters are not
-		 * available, or if no caches were reported to exist,
-		 * just accept what the HTT flag indicated.
-		 */
-		if (hyperthreading_cpus == 0)
-			hyperthreading_cpus = logical_cpus;
-	}
-}
-
-static void
 topo_probe(void)
 {
 	static int cpu_topo_probed = 0;
@@ -291,10 +278,14 @@ topo_probe(void)
 		return;
 
 	logical_cpus = logical_cpus_mask = 0;
-	if (cpu_high >= 0xb)
-		topo_probe_0xb();
-	else if (cpu_high)
-		topo_probe_0x4();
+	if (cpu_vendor_id == CPU_VENDOR_AMD)
+		topo_probe_amd();
+	else if (cpu_vendor_id == CPU_VENDOR_INTEL) {
+		if (cpu_high >= 0xb)
+			topo_probe_0xb();
+		else if (cpu_high >= 0x4)
+			topo_probe_0x4();
+	}
 	if (cpu_cores == 0)
 		cpu_cores = mp_ncpus > 0 ? mp_ncpus : 1;
 	if (cpu_logical == 0)