kvm: enable TRIM on raw images

When the image is a block device, the guest must also run Linux >= 5.0.

software/kvm/buildout.hash.cfg

@@ -55,7 +55,7 @@ md5sum = 2036bf145f472f62ef8dee5e729328fd
 
 [template-kvm-run]
 filename = template/template-kvm-run.in
-md5sum = 2a49e6065a3f46f871318ba88f0cd235
+md5sum = 2c3e788632910a061b5272dfef5caa73
 
 [template-kvm-controller]
 filename = template/kvm-controller-run.in

software/kvm/template/template-kvm-run.in

@@ -242,7 +242,8 @@ additional_disk_options = ''
 
 if disk_aio == 'native':
   additional_disk_options += ',cache.direct=on'
-
+if disk_format == "raw":
+  additional_disk_options += ',discard=on'
 
 # Generate network parameters
 # XXX: use_tap should be a boolean