Re: [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&gt; --- 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 (); +