-dnl back to basic 'qemu'.
-AC_PATH_PROGS([QEMU],[qemu-system-$host_cpu qemu],[no],
+dnl back to basic 'qemu'. Allow the user to override it.
+default_qemu="qemu-system-$host_cpu qemu"
+# On x86-64, try using KVM first.
+if test "x$host_cpu" = "xx86_64"; then
+ default_qemu="qemu-kvm $default_qemu"
+fi
+AC_ARG_WITH([qemu],
+ [AS_HELP_STRING([--with-qemu],
+ [set default QEMU binary @<:@default=[qemu-kvm] qemu-system-<host> qemu@:>@])],
+ [],
+ [with_qemu="$default_qemu"])
+AC_PATH_PROGS([QEMU],[$with_qemu],[no],