[Libguestfs] [v2v PATCH 3/9] create_libvirt_xml: normalize match on (s_cpu_vendor, s_cpu_model)

20 Apr 2022

In the match on (s_cpu_vendor, s_cpu_model), the following expression is
duplicated:

  e "model" ["fallback", "allow"] [PCData model]

For eliminating this, normalize the match: match each component in
separation, in the proper order, creating a tree-like match rather than a
table-like one.

This is done in preparation for a subsequent patch, which would otherwise
duplicate even more code.

We preserve the behavior added by commit 2a576b7cc5c3 ("v2v: -o libvirt:
Don't write only <vendor> without <model> (RHBZ#1591789).", 2018-06-21);
the change only simplifies the code.

With the elimination of the table-like pattern matching, we need not
specifically mention the "CPU vendor specified without CPU model" libvirt
error.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2076013
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 output/create_libvirt_xml.ml | 22 ++++++++------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/output/create_libvirt_xml.ml b/output/create_libvirt_xml.ml
index 4e5bbceffabd..d2ca894d60bb 100644
--- a/output/create_libvirt_xml.ml
+++ b/output/create_libvirt_xml.ml
@@ -161,65 +161,61 @@ let create_libvirt_xml ?pool source inspect
   );
 
 
   (match get_osinfo_id inspect with
    | None -> ()
    | Some osinfo_id ->
      List.push_back_list body [
        e "metadata" [] [
          e "libosinfo:libosinfo" ["xmlns:libosinfo", "http://libosinfo.org/xmlns/libvirt/domain/1.0"] [
            e "libosinfo:os" ["id", osinfo_id] [];
          ];
        ];
      ];
   );
 
   let memory_k = source.s_memory /^ 1024L in
   List.push_back_list body [
     e "memory" ["unit", "KiB"] [PCData (Int64.to_string memory_k)];
     e "currentMemory" ["unit", "KiB"] [PCData (Int64.to_string memory_k)];
     e "vcpu" [] [PCData (string_of_int source.s_vcpu)]
   ];
 
   if source.s_cpu_vendor <> None || source.s_cpu_model <> None ||
      source.s_cpu_topology <> None then (
     let cpu = ref [] in
 
-    (match source.s_cpu_vendor, source.s_cpu_model with
-     | _, None ->
-         (* This also avoids the libvirt error:
-          * "CPU vendor specified without CPU model".
-          *)
-         ()
-     | None, Some model ->
-        List.push_back cpu (e "model" ["fallback", "allow"] [PCData model])
-     | Some vendor, Some model ->
-        List.push_back_list cpu [
-          e "vendor" [] [PCData vendor];
-          e "model" ["fallback", "allow"] [PCData model]
-        ]
+    (match source.s_cpu_model with
+     | None -> ()
+     | Some model ->
+         (match source.s_cpu_vendor with
+          | None -> ()
+          | Some vendor ->
+              List.push_back cpu (e "vendor" [] [PCData vendor])
+         );
+         List.push_back cpu (e "model" ["fallback", "allow"] [PCData model])
     );
     (match source.s_cpu_topology with
      | None -> ()
      | Some { s_cpu_sockets; s_cpu_cores; s_cpu_threads } ->
         let topology_attrs = [
           "sockets", string_of_int s_cpu_sockets;
           "cores", string_of_int s_cpu_cores;
           "threads", string_of_int s_cpu_threads;
         ] in
         List.push_back cpu (e "topology" topology_attrs [])
     );
 
     List.push_back_list body [ e "cpu" [ "match", "minimum" ] !cpu ]
   );
 
   let uefi_firmware =
     match target_firmware with
     | TargetBIOS -> None
     | TargetUEFI -> Some (find_uefi_firmware guestcaps.gcaps_arch) in
   let machine, secure_boot_required =
     match guestcaps.gcaps_machine, uefi_firmware with
     | _, Some { Uefi.flags = flags }
          when List.mem Uefi.UEFI_FLAG_SECURE_BOOT_REQUIRED flags ->
        (* Force machine type to Q35 because PC does not support
         * secure boot.  We must remove this when we get the
         * correct machine type from libosinfo in future. XXX
-- 
2.19.1.3.g30247aa5d201

    