diff --git a/boards/x86_64/qemu_x86_64/Kconfig.defconfig b/boards/x86_64/qemu_x86_64/Kconfig.defconfig
index 172733baf74..7cdfe47ee28 100644
--- a/boards/x86_64/qemu_x86_64/Kconfig.defconfig
+++ b/boards/x86_64/qemu_x86_64/Kconfig.defconfig
@@ -6,4 +6,9 @@ config BUILD_OUTPUT_BIN
 config BOARD
 	default "qemu_x86_64"
 
+# In theory we could ask qemu for any configuration, but this seems
+# like a good default.
+config MP_NUM_CPUS
+	default 2
+
 endif # BOARD_QEMU_X86_64
diff --git a/soc/x86_64/x86_64/Kconfig.defconfig b/soc/x86_64/x86_64/Kconfig.defconfig
index 5a9693d0faa..0e954bb1ee0 100644
--- a/soc/x86_64/x86_64/Kconfig.defconfig
+++ b/soc/x86_64/x86_64/Kconfig.defconfig
@@ -6,4 +6,10 @@ config SOC
 config USE_SWITCH
 	default y
 
+# Make this the default even if we have only one CPU, mostly for test
+# coverage.  Uniprocessor apps for production purposes can get a
+# moderate code size savings by turning it off.
+config SMP
+	default y
+
 endif