diff --git a/target/linux/x86/image/Config.in b/target/linux/x86/image/Config.in
index 308f85cca49..ac7510edbc2 100644
--- a/target/linux/x86/image/Config.in
+++ b/target/linux/x86/image/Config.in
@@ -14,8 +14,8 @@ config X86_GRUB_CONSOLE
 config X86_GRUB_SERIAL
 	string "Serial port device"
 	depends X86_GRUB_IMAGES
-	default "hvc0" if TARGET_x86_xen_domu
-	default "ttyS0"
+	default "hvc0" if (TARGET_x86_kvm_guest || TARGET_x86_xen_domu)
+	default "ttyS0" if ! (TARGET_x86_kvm_guest || TARGET_x86_xen_domu)
 
 config X86_GRUB_BAUDRATE
 	int "Serial port baud rate"
@@ -63,8 +63,9 @@ config TARGET_KERNEL_PARTSIZE
 config TARGET_ROOTFS_PARTNAME
 	string "Root partition on target device"
 	depends OLPC_BOOTSCRIPT_IMAGES || X86_GRUB_IMAGES
+	default "/dev/vda2" if TARGET_x86_kvm_guest
 	default "/dev/xvda2" if TARGET_x86_xen_domu
-	default "/dev/sda2"
+	default "/dev/sda2" if ! (TARGET_x86_kvm_guest || TARGET_x86_xen_domu)
 	help
 	  The root partition on the final device.  If you don't know,
 	  you probably want the default (/dev/sda2).