+# Append other parameters to nested command line.
+append="$append supernested.smp=$smp supernested.tcg=$tcg"
+
+extra_args=
+if [ -n "$smp" ]; then extra_args="$extra_args -smp $smp"; fi
+if [ -n "$tcg" ]; then
+ extra_args="$extra_args -machine accel=tcg"
+else
+ extra_args="$extra_args -cpu host -machine accel=kvm"
+fi
+