Index: sys/dev/cpuctl/cpuctl.c
===================================================================
--- sys/dev/cpuctl/cpuctl.c
+++ sys/dev/cpuctl/cpuctl.c
@@ -405,10 +405,11 @@
 }
 
 static int
-update_amd(int cpu, cpuctl_update_args_t *args, struct thread *td)
+update_amd(int cpu __unused, cpuctl_update_args_t *args, struct thread *td)
 {
+	cpuset_t cpus;
 	void *ptr;
-	int ret;
+	int i, ret;
 
 	if (args->size == 0 || args->data == NULL) {
 		DPRINTF("[cpuctl,%d]: zero-sized firmware image", __LINE__);
@@ -431,7 +432,21 @@
 		ret = EFAULT;
 		goto fail;
 	}
-	smp_rendezvous(NULL, amd_ucode_wrmsr, NULL, ptr);
+
+	/*
+	 * Update microcode on each physical CPU.
+	 */
+#ifdef SMP
+	CPU_ZERO(&cpus);
+	CPU_FOREACH(i) {
+		if (!CPU_ISSET(i, &logical_cpus_mask))
+			CPU_SET(i, &cpus);
+	}
+#else
+	CPU_FILL(&cpus);
+	(void)i;
+#endif
+	smp_rendezvous_cpus(cpus, NULL, amd_ucode_wrmsr, NULL, ptr);
 	ret = 0;
 fail:
 	free(ptr, M_CPUCTL);