address @palainp review comment, and close the vcpu on teardown

This pushes a vmctx * vcpu pair through to the OCaml layer.

stats/albatross_stats_pure.ml

@@ -13,12 +13,14 @@ external sysctl_ifdata : int -> Stats.ifdata = "vmmanage_sysctl_ifdata"
 
 type vmctx
 
-external vmmapi_open : string -> vmctx = "vmmanage_vmmapi_open"
-external vmmapi_close : vmctx -> unit = "vmmanage_vmmapi_close"
-external vmmapi_stats : vmctx -> (string * int64) list = "vmmanage_vmmapi_stats"
+type vcpu
+
+external vmmapi_open : string -> (vmctx * vcpu) = "vmmanage_vmmapi_open"
+external vmmapi_close : vmctx -> vcpu -> unit = "vmmanage_vmmapi_close"
+external vmmapi_stats : vmctx -> vcpu -> (string * int64) list = "vmmanage_vmmapi_stats"
 
 type 'a t = {
-  pid_nic : ((vmctx, int) result * string * (string * int * string) list) IM.t ;
+  pid_nic : ((vmctx * vcpu, int) result * string * (string * int * string) list) IM.t ;
   vmid_pid : int Vmm_trie.t ;
   name_sockets : 'a Vmm_trie.t ;
 }
@@ -51,7 +53,7 @@ let remove_vmid t vmid =
   | Some pid ->
     Logs.info (fun m -> m "removing pid %d" pid) ;
     (match IM.find_opt pid t.pid_nic with
-     | Some (Ok vmctx, _, _) -> ignore (wrap vmmapi_close vmctx) ; vmmapi `Close
+     | Some (Ok (vmctx, vcpu), _, _) -> ignore (wrap (vmmapi_close vmctx) vcpu) ; vmmapi `Close
      | _ -> ()) ;
     let pid_nic = IM.remove pid t.pid_nic
     and vmid_pid = Vmm_trie.remove vmid t.vmid_pid
@@ -204,7 +206,7 @@ let gather pid vmctx nics =
   ru, mem,
   (match vmctx with
    | Error _ -> None
-   | Ok vmctx -> wrap vmmapi_stats vmctx),
+   | Ok (vmctx, vcpu) -> wrap (vmmapi_stats vmctx) vcpu),
   List.fold_left (fun ifd (bridge, nic, nname) ->
       match wrap sysctl_ifdata nic with
       | None ->

stats/albatross_stats_stubs.c

@@ -110,34 +110,48 @@ CAMLprim value vmmanage_vmmapi_open (value name) {
   CAMLparam1(name);
   struct vmctx *ctx;
   const char *devname;
+  CAMLlocal1(res);
 
   if (! caml_string_is_c_safe(name)) caml_raise_not_found();
 
   devname = String_val(name);
   ctx = vm_open(devname);
   if (ctx == NULL) uerror("vm_open", Nothing);
-  CAMLreturn((value)ctx);
+  struct vcpu *vcpu;
+#if __FreeBSD_version >= 1400000
+  vcpu = vm_vcpu_open(ctx, 0);
+#else
+  vcpu = NULL;
+#endif
+  res = caml_alloc(2, 0);
+  Store_field (res, 1, (value)ctx);
+  Store_field (res, 0, (value)vcpu);
+  CAMLreturn(res);
 }
 
-CAMLprim value vmmanage_vmmapi_close (value octx) {
+CAMLprim value vmmanage_vmmapi_close (value octx, value ovcpu) {
   struct vmctx *ctx = (struct vmctx*)octx;
+  struct vcpu *vcpu = (struct vcpu*)ovcpu;
+
+#if __FreeBSD_version >= 1400000
+  vm_vcpu_close(vcpu);
+#endif
 
   close(vm_get_device_fd(ctx));
   free(ctx);
   return Val_unit;
 }
 
-CAMLprim value vmmanage_vmmapi_stats (value octx) {
+CAMLprim value vmmanage_vmmapi_stats (value octx, value ovcpu) {
   CAMLparam0();
   CAMLlocal3(res, tmp, pair);
   int i, num_stats;
   uint64_t *stats;
   const char *desc;
   struct vmctx *ctx = (struct vmctx*)octx;
+  struct vcpu *vcpu = (struct vcpu*)ovcpu;
 
 #if __FreeBSD_version >= 1400000
-  struct vcpu *vcpu;
-  vcpu = vm_vcpu_open(ctx, 0);
   stats = vm_get_stats(vcpu, NULL, &num_stats);
 #else
   stats = vm_get_stats(ctx, 0, NULL, &num_stats);