CA-421914: preserve Host.numa_affinity_policy across pool join (#6796)

When `numa-placement` was true (the default in XS9), configuring a
host's `numa-affinity-policy` to `any` got lost during pool join.

This is because `create_params` is maintained by hand and needs to be
extended every time we add a new field to the datamodel.

Update `create_params` to propagate `numa_affinity_policy` on pool join.

Before pool join:
```
[root@genuk-21-09d ~]# xe host-list params=all|grep numa
                  numa-affinity-policy ( RW): any
```

After pool join:
```
[root@genuk-21-09d ~]# xe host-list params=all|grep numa
                  numa-affinity-policy ( RW): any
                  numa-affinity-policy ( RW): any
```

(prior to this bugfix the newly joined host would revert to
default_policy).

The correct policy is also set in xenopsd:
```
2025-12-15T15:12:09.029478+00:00 genuk-21-09d xenopsd-xc: [ info||134
|host.set_numa_affinity_policy R:99aecf4c494f|xenops_server] Enforcing 'any'
NUMA affinity policy
```

Author: edwintorok

ocaml/idl/datamodel_host.ml

@@ -1209,6 +1209,23 @@ let license_remove =
        to the unlicensed edition"
     ~allowed_roles:_R_POOL_OP ()
 
+let host_numa_affinity_policy =
+  Enum
+    ( "host_numa_affinity_policy"
+    , [
+        ("any", "VMs are spread across all available NUMA nodes")
+      ; ( "best_effort"
+        , "VMs are placed on the smallest number of NUMA nodes that they fit \
+           using soft-pinning, but the policy doesn't guarantee a balanced \
+           placement, falling back to the 'any' policy."
+        )
+      ; ( "default_policy"
+        , "Use the NUMA affinity policy that is the default for the current \
+           version"
+        )
+      ]
+    )
+
 let create_params =
   [
     {
@@ -1406,6 +1423,13 @@ let create_params =
     ; param_release= numbered_release "25.38.0-next"
     ; param_default= Some (VBool false)
     }
+  ; {
+      param_type= host_numa_affinity_policy
+    ; param_name= "numa_affinity_policy"
+    ; param_doc= "NUMA-aware VM memory and vCPU placement policy"
+    ; param_release= numbered_release "25.39.0-next"
+    ; param_default= Some (VEnum "default_policy")
+    }
   ]
 
 let create =
@@ -2311,23 +2335,6 @@ let cleanup_pool_secret =
       ]
     ~allowed_roles:_R_LOCAL_ROOT_ONLY ~hide_from_docs:true ()
 
-let host_numa_affinity_policy =
-  Enum
-    ( "host_numa_affinity_policy"
-    , [
-        ("any", "VMs are spread across all available NUMA nodes")
-      ; ( "best_effort"
-        , "VMs are placed on the smallest number of NUMA nodes that they fit \
-           using soft-pinning, but the policy doesn't guarantee a balanced \
-           placement, falling back to the 'any' policy."
-        )
-      ; ( "default_policy"
-        , "Use the NUMA affinity policy that is the default for the current \
-           version"
-        )
-      ]
-    )
-
 let set_numa_affinity_policy =
   call ~name:"set_numa_affinity_policy" ~lifecycle:[]
     ~doc:"Set VM placement NUMA affinity policy"

ocaml/tests/common/test_common.ml

@@ -184,7 +184,7 @@ let make_host ~__context ?(uuid = make_uuid ()) ?(name_label = "host")
       ~last_update_hash ~ssh_enabled ~ssh_enabled_timeout ~ssh_expiry
       ~console_idle_timeout ~ssh_auto_mode ~secure_boot
       ~software_version:(Xapi_globs.software_version ())
-      ~https_only
+      ~https_only ~numa_affinity_policy:`default_policy
   in
   Db.Host.set_cpu_info ~__context ~self:host ~value:default_cpu_info ;
   host

ocaml/tests/test_host.ml

@@ -27,7 +27,7 @@ let add_host __context name =
        ~ssh_enabled:true ~ssh_enabled_timeout:0L ~ssh_expiry:Clock.Date.epoch
        ~console_idle_timeout:0L ~ssh_auto_mode:false ~secure_boot:false
        ~software_version:(Xapi_globs.software_version ())
-       ~https_only:false
+       ~https_only:false ~numa_affinity_policy:`default_policy
     )
 
 (* Creates an unlicensed pool with the maximum number of hosts *)

ocaml/xapi/dbsync_slave.ml

@@ -66,7 +66,7 @@ let create_localhost ~__context info =
         ~console_idle_timeout:Constants.default_console_idle_timeout
         ~ssh_auto_mode:!Xapi_globs.ssh_auto_mode_default
         ~secure_boot:false ~software_version:[]
-        ~https_only:!Xapi_globs.https_only
+        ~https_only:!Xapi_globs.https_only ~numa_affinity_policy:`default_policy
     in
     ()
 

ocaml/xapi/xapi_host.ml

@@ -1029,7 +1029,7 @@ let create ~__context ~uuid ~name_label ~name_description:_ ~hostname ~address
     ~license_params ~edition ~license_server ~local_cache_sr ~chipset_info
     ~ssl_legacy:_ ~last_software_update ~last_update_hash ~ssh_enabled
     ~ssh_enabled_timeout ~ssh_expiry ~console_idle_timeout ~ssh_auto_mode
-    ~secure_boot ~software_version ~https_only =
+    ~secure_boot ~software_version ~https_only ~numa_affinity_policy =
   (* fail-safe. We already test this on the joining host, but it's racy, so multiple concurrent
      pool-join might succeed. Note: we do it in this order to avoid a problem checking restrictions during
      the initial setup of the database *)
@@ -1073,8 +1073,7 @@ let create ~__context ~uuid ~name_label ~name_description:_ ~hostname ~address
     ~name_label ~uuid ~other_config:[] ~capabilities:[]
     ~cpu_configuration:[] (* !!! FIXME hard coding *)
     ~cpu_info:[] ~chipset_info ~memory_overhead:0L
-    ~sched_policy:"credit" (* !!! FIXME hard coding *)
-    ~numa_affinity_policy:`default_policy
+    ~sched_policy:"credit" (* !!! FIXME hard coding *) ~numa_affinity_policy
     ~supported_bootloaders:(List.map fst Xapi_globs.supported_bootloaders)
     ~suspend_image_sr:Ref.null ~crash_dump_sr:Ref.null ~logging:[] ~hostname
     ~address ~metrics ~license_params ~boot_free_mem:0L ~ha_statefiles:[]

ocaml/xapi/xapi_host.mli

@@ -139,6 +139,7 @@ val create :
   -> secure_boot:bool
   -> software_version:(string * string) list
   -> https_only:bool
+  -> numa_affinity_policy:API.host_numa_affinity_policy
   -> [`host] Ref.t
 
 val destroy : __context:Context.t -> self:API.ref_host -> unit

ocaml/xapi/xapi_pool.ml

@@ -1062,6 +1062,7 @@ let rec create_or_get_host_on_master __context rpc session_id (host_ref, host) :
           ~secure_boot:host.API.host_secure_boot
           ~software_version:host.API.host_software_version
           ~https_only:host.API.host_https_only
+          ~numa_affinity_policy:host.API.host_numa_affinity_policy
       in
       (* Copy other-config into newly created host record: *)
       no_exn