xen/x86: retrieve keyboard shift status flags from hypervisor.

The xen c/s 25873 allows the hypervisor to retrieve the NUMLOCK flag.
With this patch, the Linux kernel can get the state according to the
data in the BIOS.
Acked-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/xen/enlighten.c

@@ -1440,11 +1440,19 @@ asmlinkage void __init xen_start_kernel(void)
 		const struct dom0_vga_console_info *info =
 			(void *)((char *)xen_start_info +
 				 xen_start_info->console.dom0.info_off);
+		struct xen_platform_op op = {
+			.cmd = XENPF_firmware_info,
+			.interface_version = XENPF_INTERFACE_VERSION,
+			.u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
+		};
 
 		xen_init_vga(info, xen_start_info->console.dom0.info_size);
 		xen_start_info->console.domU.mfn = 0;
 		xen_start_info->console.domU.evtchn = 0;
 
+		if (HYPERVISOR_dom0_op(&op) == 0)
+			boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags;
+
 		xen_init_apic();
 
 		/* Make sure ACS will be enabled */

include/xen/interface/platform.h

@@ -112,6 +112,7 @@ DEFINE_GUEST_HANDLE_STRUCT(xenpf_platform_quirk_t);
 #define XEN_FW_DISK_INFO          1 /* from int 13 AH=08/41/48 */
 #define XEN_FW_DISK_MBR_SIGNATURE 2 /* from MBR offset 0x1b8 */
 #define XEN_FW_VBEDDC_INFO        3 /* from int 10 AX=4f15 */
+#define XEN_FW_KBD_SHIFT_FLAGS    5 /* Int16, Fn02: Get keyboard shift flags. */
 struct xenpf_firmware_info {
 	/* IN variables. */
 	uint32_t type;
@@ -142,6 +143,8 @@ struct xenpf_firmware_info {
 			/* must refer to 128-byte buffer */
 			GUEST_HANDLE(uchar) edid;
 		} vbeddc_info; /* XEN_FW_VBEDDC_INFO */
+
+		uint8_t kbd_shift_flags; /* XEN_FW_KBD_SHIFT_FLAGS */
 	} u;
 };
 DEFINE_GUEST_HANDLE_STRUCT(xenpf_firmware_info_t);