[Libguestfs] [PATCH 2/2] v2v: remove the 'graphicsmodedisabled' entry in ESP BCD
Guest tools for Windows in Parallels / Virtuozzo Server 6 contain a
paravirtualized video driver, which wants to take full control of the video
mode. To avoid excessive video mode switches in UEFI VMs it executes
"bcdedit /set {current} graphicsmodedisabled true".
When such a VM is imported into a QEMU/KVM-based hypervisor, the
standard video drivers in Windows do not set the video mode as they
expect it to have already been configured by the bootloader. As a result,
the VM runs with black screen.
So patch the BCD store (which is a Windows registry hive with a special
structure, located on the EFI system partition) to clear this setting.
Signed-off-by: Pavel Butsykin <pbutsykin(a)virtuozzo.com>
---
v2v/convert_windows.ml | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/v2v/convert_windows.ml b/v2v/convert_windows.ml
index 62bb536..8579240 100644
--- a/v2v/convert_windows.ml
+++ b/v2v/convert_windows.ml
@@ -466,6 +466,45 @@ if errorlevel 3010 exit /b 0
ignore (g#pwrite_device rootpart bytes 0x1a_L)
)
)
+
+ and fix_win_esp () =
+ let fix_win_uefi_bcd esp_path =
+ try
+ let bcd_path = "/EFI/Microsoft/Boot/BCD" in
+ Windows.with_hive_write g (esp_path ^ bcd_path) (
+ (* Remove the 'graphicsmodedisabled' key in BCD *)
+ fun root ->
+ let path = ["Objects";
"{9dea862c-5cdd-4e70-acc1-f32b344d4795}";
+ "Elements"; "23000003"] in
+ let boot_mgr_default_link =
+ match Windows.get_node g root path with
+ | None -> raise Not_found
+ | Some node -> node in
+ let current_boot_entry = g#hivex_value_utf8 (
+ g#hivex_node_get_value boot_mgr_default_link "Element") in
+ let path = ["Objects"; current_boot_entry; "Elements";
"16000046"] in
+ match Windows.get_node g root path with
+ | None -> raise Not_found
+ | Some graphics_mode_disabled ->
+ g#hivex_node_delete_child graphics_mode_disabled
+ );
+ with
+ Not_found -> ()
+ in
+
+ let esp_temp_path = g#mkdtemp "/Windows/Temp/ESP_XXXXXX" in
+
+ match inspect.i_uefi with
+ | None -> ()
+ | Some uefi_list ->
+ List.iter (
+ fun dev_path ->
+ g#mount dev_path esp_temp_path;
+ fix_win_uefi_bcd esp_temp_path;
+ g#umount esp_temp_path;
+ ) uefi_list;
+
+ g#rmdir esp_temp_path;
in
(* Firstboot configuration. *)
@@ -480,6 +519,8 @@ if errorlevel 3010 exit /b 0
fix_ntfs_heads ();
+ fix_win_esp ();
+
(* Warn if installation of virtio block drivers might conflict with
* group policy or AV software causing a boot 0x7B error (RHBZ#1260689).
*)
--
2.8.3