Merge d9f43a3 into 1a68634

AnthoineB · web-flow · commit 35f1dbdc52ea · 2025-06-26T08:54:46.000Z
diff --git a/ocaml/idl/datamodel_common.ml b/ocaml/idl/datamodel_common.ml
@@ -10,7 +10,7 @@ open Datamodel_roles
               to leave a gap for potential hotfixes needing to increment the schema version.*)
 let schema_major_vsn = 5
 
-let schema_minor_vsn = 789
+let schema_minor_vsn = 790
 
 (* Historical schema versions just in case this is useful later *)
 let rio_schema_major_vsn = 5
diff --git a/ocaml/idl/datamodel_vm.ml b/ocaml/idl/datamodel_vm.ml
@@ -2137,6 +2137,20 @@ let set_has_vendor_device =
       ]
     ~allowed_roles:_R_VM_ADMIN ~doc_tags:[Windows] ()
 
+let set_xen_platform_pci_bar_uc =
+  call ~name:"set_xen_platform_pci_bar_uc" ~lifecycle:[]
+    ~doc:
+      "Controls whether, when the VM starts in HVM mode, the Xen PCI MMIO used \
+       by grant tables is mapped as Uncached (UC, the default) or WriteBack \
+       (WB, the workaround). WB mapping could improve performance of devices \
+       using grant tables. This is useful on AMD platform only."
+    ~params:
+      [
+        (Ref _vm, "self", "The VM on which to set this flag")
+      ; (Bool, "value", "False to enable WB MMIO bar.")
+      ]
+    ~allowed_roles:_R_VM_ADMIN ()
+
 let import =
   call ~name:"import"
     ~lifecycle:[(Published, rel_dundee, "Import an XVA from a URI")]
@@ -2560,6 +2574,7 @@ let t =
       ; call_plugin
       ; call_host_plugin
       ; set_has_vendor_device
+      ; set_xen_platform_pci_bar_uc
       ; import
       ; set_actions_after_crash
       ; set_domain_type
@@ -3097,6 +3112,19 @@ let t =
             "When an HVM guest starts, this controls the presence of the \
              emulated C000 PCI device which triggers Windows Update to fetch \
              or update PV drivers."
+        ; field ~qualifier:StaticRO
+            ~lifecycle:
+              [
+                ( Published
+                , rel_ely
+                , "Controls whether, when the VM starts in HVM mode, the MMIO \
+                   is mapped as UC or WB."
+                )
+              ]
+            ~default_value:(Some (VBool true)) ~ty:Bool
+            "xen_platform_pci_bar_uc"
+            "Controls whether, when the VM starts in HVM mode, the MMIO is \
+             mapped as UC or WB."
         ; field ~qualifier:DynamicRO ~ty:Bool
             ~lifecycle:[(Published, rel_ely, "")]
             ~default_value:(Some (VBool false)) "requires_reboot"
diff --git a/ocaml/idl/schematest.ml b/ocaml/idl/schematest.ml
@@ -3,7 +3,7 @@ let hash x = Digest.string x |> Digest.to_hex
 (* BEWARE: if this changes, check that schema has been bumped accordingly in
    ocaml/idl/datamodel_common.ml, usually schema_minor_vsn *)
 
-let last_known_schema_hash = "4cd835e2557dd7b5cbda6c681730c447"
+let last_known_schema_hash = "d6e73da8c4cd30220ac9e359d2631a60"
 
 let current_schema_hash : string =
   let open Datamodel_types in
diff --git a/ocaml/tests/common/test_common.ml b/ocaml/tests/common/test_common.ml
@@ -148,7 +148,7 @@ let make_vm ~__context ?(name_label = "name_label")
     ?(hardware_platform_version = 0L) ?has_vendor_device:_
     ?(has_vendor_device = false) ?(reference_label = "") ?(domain_type = `hvm)
     ?(nVRAM = []) ?(last_booted_record = "") ?(last_boot_CPU_flags = [])
-    ?(power_state = `Halted) () =
+    ?(power_state = `Halted) ?(xen_platform_pci_bar_uc = true) () =
   Xapi_vm.create ~__context ~name_label ~name_description ~user_version
     ~is_a_template ~affinity ~memory_target ~memory_static_max
     ~memory_dynamic_max ~memory_dynamic_min ~memory_static_min ~vCPUs_params
@@ -162,7 +162,7 @@ let make_vm ~__context ?(name_label = "name_label")
     ~shutdown_delay ~order ~suspend_SR ~suspend_VDI ~snapshot_schedule
     ~is_vmss_snapshot ~version ~generation_id ~hardware_platform_version
     ~has_vendor_device ~reference_label ~domain_type ~last_booted_record
-    ~last_boot_CPU_flags ~power_state
+    ~last_boot_CPU_flags ~power_state ~xen_platform_pci_bar_uc
 
 let make_host ~__context ?(uuid = make_uuid ()) ?(name_label = "host")
     ?(name_description = "description") ?(hostname = "localhost")
diff --git a/ocaml/xapi-cli-server/cli_operations.ml b/ocaml/xapi-cli-server/cli_operations.ml
@@ -2859,7 +2859,8 @@ let vm_create printer rpc session_id params =
       ~snapshot_schedule:Ref.null ~is_vmss_snapshot:false ~appliance:Ref.null
       ~start_delay:0L ~shutdown_delay:0L ~order:0L ~suspend_SR:Ref.null
       ~suspend_VDI:Ref.null ~version:0L ~generation_id:""
-      ~hardware_platform_version:0L ~has_vendor_device:false ~reference_label:""
+      ~hardware_platform_version:0L ~has_vendor_device:false
+      ~xen_platform_pci_bar_uc:true ~reference_label:""
       ~domain_type:`unspecified ~nVRAM:[] ~last_booted_record:""
       ~last_boot_CPU_flags:[] ~power_state:`Halted
   in
diff --git a/ocaml/xapi-cli-server/records.ml b/ocaml/xapi-cli-server/records.ml
@@ -2659,6 +2659,13 @@ let vm_record rpc session_id vm =
               ~value:(safe_bool_of_string "has-vendor-device" x)
           )
           ()
+      ; make_field ~name:"xen-platform-pci-bar-uc"
+          ~get:(fun () -> string_of_bool (x ()).API.vM_xen_platform_pci_bar_uc)
+          ~set:(fun x ->
+            Client.VM.set_xen_platform_pci_bar_uc ~rpc ~session_id ~self:vm
+              ~value:(safe_bool_of_string "xen-platform-pci-bar-uc" x)
+          )
+          ()
       ; make_field ~name:"requires-reboot"
           ~get:(fun () -> string_of_bool (x ()).API.vM_requires_reboot)
           ()
diff --git a/ocaml/xapi-idl/xen/xenops_types.ml b/ocaml/xapi-idl/xen/xenops_types.ml
@@ -171,6 +171,7 @@ module Vm = struct
     ; pci_msitranslate: bool
     ; pci_power_mgmt: bool
     ; has_vendor_device: bool [@default false]
+    ; xen_platform_pci_bar_uc: bool [@default true]
     ; generation_id: string option
   }
   [@@deriving rpcty, sexp]
diff --git a/ocaml/xapi/create_misc.ml b/ocaml/xapi/create_misc.ml
@@ -290,7 +290,8 @@ and create_domain_zero_record ~__context ~domain_zero_ref (host_info : host_info
     ~snapshot_schedule:Ref.null ~is_vmss_snapshot:false ~appliance:Ref.null
     ~start_delay:0L ~shutdown_delay:0L ~order:0L ~suspend_SR:Ref.null
     ~version:0L ~generation_id:"" ~hardware_platform_version:0L
-    ~has_vendor_device:false ~requires_reboot:false ~reference_label:""
+    ~has_vendor_device:false ~xen_platform_pci_bar_uc:true
+    ~requires_reboot:false ~reference_label:""
     ~domain_type:Xapi_globs.domain_zero_domain_type ~nVRAM:[]
     ~pending_guidances:[] ~recommended_guidances:[]
     ~pending_guidances_recommended:[] ~pending_guidances_full:[] ;
diff --git a/ocaml/xapi/import.ml b/ocaml/xapi/import.ml
@@ -622,6 +622,12 @@ module VM : HandlerTools = struct
         else
           {vm_record with API.vM_has_vendor_device= false}
       in
+      let vm_record =
+        if vm_has_field ~x ~name:"xen_platform_pci_bar_uc" then
+          vm_record
+        else
+          {vm_record with API.vM_xen_platform_pci_bar_uc= true}
+      in
       let vm_record =
         {
           vm_record with
diff --git a/ocaml/xapi/message_forwarding.ml b/ocaml/xapi/message_forwarding.ml
@@ -2054,6 +2054,11 @@ functor
           (vm_uuid ~__context self) value ;
         Local.VM.set_has_vendor_device ~__context ~self ~value
 
+      let set_xen_platform_pci_bar_uc ~__context ~self ~value =
+        info "VM.set_xen_platform_pci_bar_uc: VM = '%s' to %b"
+          (vm_uuid ~__context self) value ;
+        Local.VM.set_xen_platform_pci_bar_uc ~__context ~self ~value
+
       let set_xenstore_data ~__context ~self ~value =
         info "VM.set_xenstore_data: VM = '%s'" (vm_uuid ~__context self) ;
         Db.VM.set_xenstore_data ~__context ~self ~value ;
diff --git a/ocaml/xapi/xapi_db_upgrade.ml b/ocaml/xapi/xapi_db_upgrade.ml
@@ -530,6 +530,20 @@ let default_has_vendor_device_false =
       )
   }
 
+let default_xen_platform_pci_bar_uc_true =
+  {
+    description= "Defaulting xen_platform_pci_bar_uc true"
+  ; version= (fun x -> x < (5, 787))
+  ; fn=
+      (fun ~__context ->
+        List.iter
+          (fun self ->
+            Db.VM.set_xen_platform_pci_bar_uc ~__context ~self ~value:true
+          )
+          (Db.VM.get_all ~__context)
+      )
+  }
+
 let default_pv_drivers_detected_false =
   {
     description= "Defaulting PV_drivers_detected false"
@@ -994,6 +1008,7 @@ let rules =
   ; empty_pool_uefi_certificates
   ; upgrade_update_guidance
   ; upgrade_ca_fingerprints
+  ; default_xen_platform_pci_bar_uc_true
   ]
 
 (* Maybe upgrade most recent db *)
diff --git a/ocaml/xapi/xapi_vm.ml b/ocaml/xapi/xapi_vm.ml
@@ -582,8 +582,8 @@ let create ~__context ~name_label ~name_description ~power_state ~user_version
     ~blocked_operations:_ ~protection_policy:_ ~is_snapshot_from_vmpp:_
     ~snapshot_schedule:_ ~is_vmss_snapshot:_ ~appliance ~start_delay
     ~shutdown_delay ~order ~suspend_SR ~version ~generation_id
-    ~hardware_platform_version ~has_vendor_device ~reference_label ~domain_type
-    ~nVRAM : API.ref_VM =
+    ~hardware_platform_version ~has_vendor_device ~xen_platform_pci_bar_uc
+    ~reference_label ~domain_type ~nVRAM : API.ref_VM =
   (* Add random mac_seed if there isn't one specified already *)
   let other_config =
     let gen_mac_seed () = Uuidx.to_string (Uuidx.make ()) in
@@ -661,9 +661,10 @@ let create ~__context ~name_label ~name_description ~power_state ~user_version
     ~is_snapshot_from_vmpp:false ~snapshot_schedule:Ref.null
     ~is_vmss_snapshot:false ~appliance ~start_delay ~shutdown_delay ~order
     ~suspend_SR ~version ~generation_id ~hardware_platform_version
-    ~has_vendor_device ~requires_reboot:false ~reference_label ~domain_type
-    ~pending_guidances:[] ~recommended_guidances:[]
-    ~pending_guidances_recommended:[] ~pending_guidances_full:[] ;
+    ~has_vendor_device ~xen_platform_pci_bar_uc ~requires_reboot:false
+    ~reference_label ~domain_type ~pending_guidances:[]
+    ~recommended_guidances:[] ~pending_guidances_recommended:[]
+    ~pending_guidances_full:[] ;
   Xapi_vm_lifecycle.update_allowed_operations ~__context ~self:vm_ref ;
   update_memory_overhead ~__context ~vm:vm_ref ;
   update_vm_virtual_hardware_platform_version ~__context ~vm:vm_ref ;
@@ -1586,6 +1587,16 @@ let set_has_vendor_device ~__context ~self ~value =
   Db.VM.set_has_vendor_device ~__context ~self ~value ;
   update_vm_virtual_hardware_platform_version ~__context ~vm:self
 
+let set_xen_platform_pci_bar_uc ~__context ~self ~value =
+  (* Not inherently dangerous to modify this param outside halted state.
+     This assert helps to avoid confusion. This parameter will not change
+     dynamically the performance of a running domain. It's only checked
+     at boot. *)
+  Xapi_vm_lifecycle.assert_initial_power_state_is ~__context ~self
+    ~expected:`Halted ;
+  Db.VM.set_xen_platform_pci_bar_uc ~__context ~self ~value ;
+  update_vm_virtual_hardware_platform_version ~__context ~vm:self
+
 let set_domain_type ~__context ~self ~value =
   if value = `unspecified then
     invalid_value "domain_type" (Record_util.domain_type_to_string value) ;
diff --git a/ocaml/xapi/xapi_vm.mli b/ocaml/xapi/xapi_vm.mli
@@ -199,6 +199,7 @@ val create :
   -> generation_id:string
   -> hardware_platform_version:int64
   -> has_vendor_device:bool
+  -> xen_platform_pci_bar_uc:bool
   -> reference_label:string
   -> domain_type:API.domain_type
   -> nVRAM:(string * string) list
@@ -410,6 +411,9 @@ val call_host_plugin :
 val set_has_vendor_device :
   __context:Context.t -> self:API.ref_VM -> value:bool -> unit
 
+val set_xen_platform_pci_bar_uc :
+  __context:Context.t -> self:API.ref_VM -> value:bool -> unit
+
 val import :
      __context:Context.t
   -> url:string
diff --git a/ocaml/xapi/xapi_vm_clone.ml b/ocaml/xapi/xapi_vm_clone.ml
@@ -393,6 +393,7 @@ let copy_vm_record ?snapshot_info_record ~__context ~vm ~disk_op ~new_name
     ~suspend_SR:Ref.null ~version:0L ~generation_id
     ~hardware_platform_version:all.Db_actions.vM_hardware_platform_version
     ~has_vendor_device:all.Db_actions.vM_has_vendor_device
+    ~xen_platform_pci_bar_uc:all.Db_actions.vM_xen_platform_pci_bar_uc
     ~requires_reboot:false ~reference_label:all.Db_actions.vM_reference_label
     ~domain_type:all.Db_actions.vM_domain_type ~nVRAM:all.Db_actions.vM_NVRAM
     ~pending_guidances:[] ~recommended_guidances:[]
diff --git a/ocaml/xapi/xapi_xenops.ml b/ocaml/xapi/xapi_xenops.ml
@@ -1332,6 +1332,7 @@ module MD = struct
     ; pci_msitranslate
     ; pci_power_mgmt= false
     ; has_vendor_device= vm.API.vM_has_vendor_device
+    ; xen_platform_pci_bar_uc= vm.API.vM_xen_platform_pci_bar_uc
     ; generation_id
     }
 end
diff --git a/ocaml/xenopsd/cli/xn.ml b/ocaml/xenopsd/cli/xn.ml
@@ -585,6 +585,12 @@ let add' _copts x () =
             else
               false
           in
+          let xen_platform_pci_bar_uc =
+            if mem _vm_xen_platform_pci_bar_uc then
+              find _vm_xen_platform_pci_bar_uc |> bool
+            else
+              true
+          in
           let vm =
             {
               id= uuid
@@ -617,6 +623,7 @@ let add' _copts x () =
             ; pci_msitranslate
             ; pci_power_mgmt
             ; has_vendor_device
+            ; xen_platform_pci_bar_uc
             ; generation_id= None
             }
           in
diff --git a/ocaml/xenopsd/cli/xn_cfg_types.ml b/ocaml/xenopsd/cli/xn_cfg_types.ml
@@ -86,4 +86,6 @@ let _vm_pci_power_mgmt = "pci_power_mgmt"
 
 let _vm_has_vendor_device = "has_vendor_device"
 
+let _vm_xen_platform_pci_bar_uc = "xen_platform_pci_bar_uc"
+
 let _vtpm = "vtpm"
diff --git a/ocaml/xenopsd/test/test.ml b/ocaml/xenopsd/test/test.ml
@@ -252,6 +252,7 @@ let create_vm vmid =
   ; pci_msitranslate= true
   ; pci_power_mgmt= false
   ; has_vendor_device= false
+  ; xen_platform_pci_bar_uc= true
   ; generation_id= None
   }
 
diff --git a/ocaml/xenopsd/xc/domain.ml b/ocaml/xenopsd/xc/domain.ml
@@ -120,6 +120,7 @@ type create_info = {
   ; platformdata: (string * string) list
   ; bios_strings: (string * string) list
   ; has_vendor_device: bool
+  ; xen_platform_pci_bar_uc: bool
   ; is_uefi: bool
   ; pci_passthrough: bool
 }
@@ -501,6 +502,8 @@ let make ~xc ~xs vm_info vcpus domain_config uuid final_uuid no_sharept =
     xs.Xs.writev (dom_path ^ "/bios-strings") vm_info.bios_strings ;
     if vm_info.is_uefi then
       xs.Xs.write (dom_path ^ "/hvmloader/bios") "ovmf" ;
+    if vm_info.xen_platform_pci_bar_uc = false then
+      xs.Xs.write (dom_path ^ "/hvmloader/pci/xen-platform-pci-bar-uc") "0" ;
     (* If a toolstack sees a domain which it should own in this state then the
        domain is not completely setup and should be shutdown. *)
     xs.Xs.write (dom_path ^ "/action-request") "poweroff" ;
diff --git a/ocaml/xenopsd/xc/domain.mli b/ocaml/xenopsd/xc/domain.mli
@@ -85,6 +85,7 @@ type create_info = {
   ; platformdata: (string * string) list
   ; bios_strings: (string * string) list
   ; has_vendor_device: bool
+  ; xen_platform_pci_bar_uc: bool
   ; is_uefi: bool
   ; pci_passthrough: bool
 }
diff --git a/ocaml/xenopsd/xc/xenops_server_xen.ml b/ocaml/xenopsd/xc/xenops_server_xen.ml
@@ -1363,6 +1363,7 @@ module VM = struct
     ; platformdata
     ; bios_strings= vm.bios_strings
     ; has_vendor_device= vm.has_vendor_device
+    ; xen_platform_pci_bar_uc= vm.xen_platform_pci_bar_uc
     ; is_uefi
     ; pci_passthrough
     }

Original file line number	Diff line number	Diff line change
`@@ -171,6 +171,7 @@ module Vm = struct`
`171`	`171`	`; pci_msitranslate: bool`
`172`	`172`	`; pci_power_mgmt: bool`
`173`	`173`	`; has_vendor_device: bool [@default false]`
	`174`	`+ ; xen_platform_pci_bar_uc: bool [@default true]`
`174`	`175`	`; generation_id: string option`
`175`	`176`	`}`
`176`	`177`	`[@@deriving rpcty, sexp]`