with current main branch, there's regression (network interface names)

[hannesm]

When I have a unikernel that uses the default_network interface, now (with #1455 merged) I get in the generated manifest.json (using mirage configure -t hvt e.g. on the mirage-skeleton/device-usage/network unikernel):

{
  "type": "solo5.manifest",
  "version": 1,
  "devices": [ { "name": "net0", "type": "NET_BASIC" } ]
}

So, the name should be service, not net0. There is in mirage_impl_network a match_impl Key.(value target) -- but I fail to understand how the net0 comes into place (the default is "0").

Previously the generated manifest was:

{
  "type": "solo5.manifest",
  "version": 1,
  "devices": [ { "name": "service", "type": "NET_BASIC" } ]
}

[hannesm]

I tested with 944a83a (the one before the #1455 merge), and this still works nicely (having service in the manifest.json).

[hannesm]

The culprit seems to be caabf33, which includes:

--- a/lib/mirage/impl/mirage_impl_network.ml
+++ b/lib/mirage/impl/mirage_impl_network.ml
@@ -1,14 +1,18 @@
 open Functoria
 module Key = Mirage_key
+module Runtime_key = Mirage_runtime_key
 
 type network = NETWORK
 
 let network = Type.v NETWORK
 let all_networks = ref []
 
-let network_conf (intf : string Key.key) =
-  let key = Key.v intf in
-  let keys = [ key ] in
+let add_new_network () =
+  let device = Fmt.str "net%d" (List.length !all_networks) in
+  all_networks := device :: !all_networks
+
+let network_conf (intf : string runtime_key) =
+  let runtime_keys = [ Runtime_key.v intf ] in
   let packages_v =
     Key.match_ Key.(value target) @@ function
     | `Unix -> [ package ~min:"3.0.0" ~max:"4.0.0" "mirage-net-unix" ]
@@ -23,16 +27,15 @@ let network_conf (intf : string Key.key) =
         [ package ~min:"0.8.0" ~max:"0.9.0" "mirage-net-solo5" ]
   in
   let connect _ modname _ =
-    (* @samoht: why not just use the args paramater? *)
-    Fmt.str "%s.connect %a" modname Key.serialize_call key
+    Fmt.str "%s.connect %a" modname Runtime_key.call intf
   in
-  let configure i =
-    all_networks := Key.get (Info.context i) intf :: !all_networks;
+  let configure _ =
+    add_new_network ();
     Action.ok ()
   in
-  impl ~keys ~packages_v ~connect ~configure "Netif" network
+  impl ~runtime_keys ~packages_v ~connect ~configure "Netif" network
 
-let netif ?group dev = network_conf @@ Key.interface ?group dev
+let netif ?group dev = network_conf @@ Runtime_key.interface ?group dev
 
 let default_network =
   match_impl

My gut feeling is that the interface should be a configure-time key!? Hmm, I'm actually not entirely sure:

• on solo5 (hvt/spt), we specify the name at configuration time (which ends up in the manifest), the value is relevant for solo5-hvt/solo5-spt (i.e. solo5-hvt --net:service=tapX -- dist/network.hvt)
• virtio supports only a single network interface
• muen I don't remember the exact semantics
• on unix/xen, I fail to understand what is happening there!?

[hannesm]

@samoht please review #1480, I tested it locally with hvt target, and it works nicely. (of course, a test in the testsuite would be welcome, but I fail to understand how to achieve that -- esp. with network devices and block devices and all the different targets)

[hannesm]

this has been fixed by #1480 (which was re-submitted as #1492)