boot windows OS from NetBSD boot loader

boot_win.patch

diff --git a/sys/stand/efiboot/boot.c b/sys/stand/efiboot/boot.c
index fab2dc2ef4e2..760c82646257 100644
--- a/sys/stand/efiboot/boot.c
+++ b/sys/stand/efiboot/boot.c
@@ -84,6 +84,7 @@ int	set_bootfile(const char *);
 int	set_bootargs(const char *);
 
 void	command_boot(char *);
+void    command_loadwin(char *);
 void	command_dev(char *);
 void	command_dtb(char *);
 void	command_plist(char *);
@@ -101,6 +102,7 @@ void	command_quit(char *);
 
 const struct boot_command commands[] = {
 	{ "boot",	command_boot,		"boot [dev:][filename] [args]\n     (ex. \"hd0a:\\netbsd.old -s\"" },
+    { "loadwin", command_loadwin,      "boot Windows OS" },
 	{ "dev",	command_dev,		"dev" },
 	{ "dtb",	command_dtb,		"dtb [dev:][filename]" },
 	{ "plist",	command_plist,		"plist [dev:][filename]" },
@@ -149,6 +151,12 @@ command_boot(char *arg)
 	exec_netbsd(kernel, bootargs);
 }
 
+void
+command_loadwin(char *arg)
+{
+    exec_windows();
+}
+
 void
 command_dev(char *arg)
 {
diff --git a/sys/stand/efiboot/efiboot.c b/sys/stand/efiboot/efiboot.c
index e375027707ba..8f12a4bd384b 100644
--- a/sys/stand/efiboot/efiboot.c
+++ b/sys/stand/efiboot/efiboot.c
@@ -248,3 +248,29 @@ efi_progress(const char *fmt, ...)
 	vprintf(fmt, ap);
 	va_end(ap);
 }
+
+void
+exec_windows(void)
+{
+    EFI_STATUS status;
+    EFI_DEVICE_PATH path;
+    EFI_HANDLE windowsBootManager;
+
+    path = FileDevicePath(efi_li->DeviceHandle, L"\\EFI\\Microsoft\\Boot\\bootmgfw.efi");
+    if (path == NULL) {
+        printf("WARNING: cannot find Windows Boot Manager\n");
+        return;
+    }
+
+    status = uefi_call_wrapper(BS->LoadImage, 6, false, IH, path, NULL, 0, &windowsBootManager);
+    if (EFI_ERROR(status)) {
+        printf("WARNING: cannot load Windows Boot Manager\n");
+        return;
+    }
+
+    status = uefi_call_wrapper(BS->StartImage, 3, windowsBootManager, NULL, NULL);
+    uefi_call_wrapper(BS->UnloadImage, 1, windowsBootManager);
+    FreePool(path);
+
+    return;
+}
diff --git a/sys/stand/efiboot/efiboot.h b/sys/stand/efiboot/efiboot.h
index d3f84c047714..40afb52c9997 100644
--- a/sys/stand/efiboot/efiboot.h
+++ b/sys/stand/efiboot/efiboot.h
@@ -78,6 +78,7 @@ void efi_cleanup(void);
 void efi_exit(void);
 void efi_delay(int);
 void efi_reboot(void);
+void exec_windows(void);
 extern int howto;
 extern prop_dictionary_t efibootplist;