Use the correct qemu emulator based on the architecture.
We want to get away from using the old qemu-dm emulator
for Xen HVM guests so default to qemu-system-i386.
Index: virt-manager-4.0.0/virtinst/guest.py
===================================================================
--- virt-manager-4.0.0.orig/virtinst/guest.py
+++ virt-manager-4.0.0/virtinst/guest.py
@@ -778,6 +778,10 @@ class Guest(XMLBuilder):
         self._add_default_tpm()
 
         self.clock.set_defaults(self)
+        if self.os.is_hvm() and self.type == "xen":
+            # Force not using Xen's old qemu-dm
+            if not self.emulator or "qemu-dm" in self.emulator:
+                self.emulator = "/usr/lib/xen/bin/qemu-system-i386"
         self.cpu.set_defaults(self)
         self.features.set_defaults(self)
         for seclabel in self.seclabels: