4 files changed, 45 insertions, 12 deletions
diff --git a/src/cpu/intel/hyperthreading/intel_sibling.c b/src/cpu/intel/hyperthreading/intel_sibling.c
index 2d2e105f8d..b9a9ae7bb1 100644
--- a/src/cpu/intel/hyperthreading/intel_sibling.c
+++ b/src/cpu/intel/hyperthreading/intel_sibling.c
@@ -14,6 +14,27 @@
 static int first_time = 1;
 static int disable_siblings = !CONFIG_LOGICAL_CPUS;
 
+/* Return true if running thread does not have the smallest lapic ID
+ * within a CPU core.
+ */
+int intel_ht_sibling(void)
+{
+	unsigned int core_ids, apic_ids, threads;
+
+	apic_ids = 1;
+	if (cpuid_eax(0) >= 1)
+		apic_ids = (cpuid_ebx(1) >> 16) & 0xff;
+	if (apic_ids < 1)
+		apic_ids = 1;
+
+	core_ids = 1;
+	if (cpuid_eax(0) >= 4)
+		core_ids += (cpuid_eax(4) >> 26) & 0x3f;
+
+	threads = (apic_ids / core_ids);
+	return !!(lapicid() & (threads-1));
+}
+
 void intel_sibling_init(device_t cpu)
 {
 	unsigned i, siblings;
diff --git a/src/cpu/intel/model_f2x/model_f2x_init.c b/src/cpu/intel/model_f2x/model_f2x_init.c
index ec78672de6..8fd8abc7bf 100644
--- a/src/cpu/intel/model_f2x/model_f2x_init.c
+++ b/src/cpu/intel/model_f2x/model_f2x_init.c
@@ -48,11 +48,15 @@ static void model_f2x_init(device_t cpu)
 {
 	/* Turn on caching if we haven't already */
 	x86_enable_cache();
-	x86_setup_mtrrs();
-	x86_mtrr_check();
 
-	/* Update the microcode */
-	intel_update_microcode(microcode_updates);
+	if (!intel_ht_sibling()) {
+		/* MTRRs are shared between threads */
+		x86_setup_mtrrs();
+		x86_mtrr_check();
+
+		/* Update the microcode */
+		intel_update_microcode(microcode_updates);
+	}
 
 	/* Enable the local cpu apics */
 	setup_lapic();
diff --git a/src/cpu/intel/model_f3x/model_f3x_init.c b/src/cpu/intel/model_f3x/model_f3x_init.c
index 580c98b4d7..2504ba9423 100644
--- a/src/cpu/intel/model_f3x/model_f3x_init.c
+++ b/src/cpu/intel/model_f3x/model_f3x_init.c
@@ -31,11 +31,15 @@ static void model_f3x_init(device_t cpu)
 {
 	/* Turn on caching if we haven't already */
 	x86_enable_cache();
-	x86_setup_mtrrs();
-	x86_mtrr_check();
 
-	/* Update the microcode */
-	intel_update_microcode(microcode_updates);
+	if (!intel_ht_sibling()) {
+		/* MTRRs are shared between threads */
+		x86_setup_mtrrs();
+		x86_mtrr_check();
+
+		/* Update the microcode */
+		intel_update_microcode(microcode_updates);
+	}
 
 	/* Enable the local cpu apics */
 	setup_lapic();
diff --git a/src/cpu/intel/model_f4x/model_f4x_init.c b/src/cpu/intel/model_f4x/model_f4x_init.c
index 54edf2e335..f3f0b2af0f 100644
--- a/src/cpu/intel/model_f4x/model_f4x_init.c
+++ b/src/cpu/intel/model_f4x/model_f4x_init.c
@@ -39,11 +39,15 @@ static void model_f4x_init(device_t cpu)
 {
 	/* Turn on caching if we haven't already */
 	x86_enable_cache();
-	x86_setup_mtrrs();
-	x86_mtrr_check();
 
-	/* Update the microcode */
-	intel_update_microcode(microcode_updates);
+	if (!intel_ht_sibling()) {
+		/* MTRRs are shared between threads */
+		x86_setup_mtrrs();
+		x86_mtrr_check();
+
+		/* Update the microcode */
+		intel_update_microcode(microcode_updates);
+	}
 
 	/* Enable the local cpu apics */
 	setup_lapic();