xen/vga: add the xen EFI video mode support

In order to add xen EFI frambebuffer video support, it is required to add
xen-efi's new video type (XEN_VGATYPE_EFI_LFB) case and handle it in the
function xen_init_vga and set the video type to VIDEO_TYPE_EFI to enable
efi video mode.

The original patch from which this was broken out from:
 http://marc.info/?i=4E099AA6020000780004A4C6@nat28.tlf.novell.com

Signed-off-by: Jan Beulich <JBeulich@novell.com>
Signed-off-by: Tang Liang <liang.tang@oracle.com>
[v2: The original author is Jan Beulich and Liang Tang ported it to upstream]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/xen/vga.c

@@ -35,6 +35,7 @@ void __init xen_init_vga(const struct dom0_vga_console_info *info, size_t size)
 			info->u.text_mode_3.font_height;
 		break;
 
+	case XEN_VGATYPE_EFI_LFB:
 	case XEN_VGATYPE_VESA_LFB:
 		if (size < offsetof(struct dom0_vga_console_info,
 				    u.vesa_lfb.gbl_caps))
@@ -54,6 +55,12 @@ void __init xen_init_vga(const struct dom0_vga_console_info *info, size_t size)
 		screen_info->blue_pos = info->u.vesa_lfb.blue_pos;
 		screen_info->rsvd_size = info->u.vesa_lfb.rsvd_size;
 		screen_info->rsvd_pos = info->u.vesa_lfb.rsvd_pos;
+
+		if (info->video_type == XEN_VGATYPE_EFI_LFB) {
+			screen_info->orig_video_isVGA = VIDEO_TYPE_EFI;
+			break;
+		}
+
 		if (size >= offsetof(struct dom0_vga_console_info,
 				     u.vesa_lfb.gbl_caps)
 		    + sizeof(info->u.vesa_lfb.gbl_caps))

include/xen/interface/xen.h

@@ -454,6 +454,7 @@ struct dom0_vga_console_info {
 	uint8_t video_type;
 #define XEN_VGATYPE_TEXT_MODE_3 0x03
 #define XEN_VGATYPE_VESA_LFB    0x23
+#define XEN_VGATYPE_EFI_LFB     0x70
 
 	union {
 		struct {