The nec-xhci virtual USB controller + tails-persistence-setup causes a VM freeze on Debian Stretch or newer hosts

While running the tests for Tails 2.10~rc1 I needed this:

--- a/features/domains/default.xml
+++ b/features/domains/default.xml
@@ -18,7 +18,9 @@
   <on_crash>restart</on_crash>
   <devices>
     <emulator>/usr/bin/qemu-system-x86_64</emulator>
-    <controller type='usb' index='0' model='nec-xhci'/>
+    <controller type='usb' index='0' model='ich9-ehci1'/>
+    <controller type='usb' index='0' model='ich9-uhci1'/>
+    <controller type='ide' index='0'/>
     <controller type='sata' index='0'/>
     <controller type='virtio-serial' index='0'/>
     <interface type='network'>

Otherwise the testing VM sort of froze — some things worked, some not. It seemed like the USB controller got messed up. Indeed, I was tail:ing the journal, and some sort of USB controller reset was logged at the exact moment stuff stopped working.

Related issues

• Related to #11588 (closed)
• Blocks #13240 (closed)

Original created by @anonym on 12142 (Redmine)