+=item B<--accel>=kvm
+
+=item B<--accel>=tcg
+
+=item B<--accel>=kvm:tcg
+
+This sets the C<-machine accel=...> parameter which is passed to
+qemu.
+
+If not set, then C<kvm:tcg> is the default, which means to try to use
+KVM (hardware-assisted virtualization), and fall back to software
+emulation if KVM is not possible.
+
+Other typical values of this parameter are: C<tcg>, which means to
+force software emulation. C<kvm>, which means to force KVM and fail
+if KVM is unavailable.
+
+=item B<--cpu>=CPU
+
+Set the qemu I<--cpu> option. If not set then a suitable default is
+picked depending on the architecture and whether KVM is available.
+You can also use I<--cpu=> to let qemu pick the default.
+