-QB_CPU_qemux86-64 = " -cpu Nehalem,check=false"
-QB_MACHINE_qemux86-64 = "-machine q35"
+
+# QEMU / runqemu options (partly overrides qemuboot-x86.inc)
+QB_MACHINE = "-machine q35"
+QB_SYSTEM_NAME_x86-64 = "qemu-system-x86_64"
+QB_CPU_x86-64 = "-cpu qemu64,+ssse3,+sse4.1,+sse4.2,+popcnt"
+QB_CPU_KVM_x86-64 = "-cpu kvm64 -cpu qemu64,+ssse3,+sse4.1,+sse4.2,+popcnt"
+
+# Add the 'virtio-rng-pci' device otherwise the guest may run out of entropy
+QB_OPT_APPEND = "-vga vmware -show-cursor -usb -usbdevice tablet -device virtio-rng-pci"