loader.efi: Fix off by one error in size of the virtual disk

The end address is the final byte in the array, not one byte past the
end of the array, so we need to add 1 to get the full length.

Fixes: 59219fc76a4b ("loader.efi: efiblk_memdisk_preload passes the VirtualDisks to FreeBSD")
Sponsored by: Netflix
Differential Revision:	https://reviews.freebsd.org/D58069

1 files changed, 1 insertions, 1 deletions

diff --git a/stand/efi/libefi/efipart.c b/stand/efi/libefi/efipart.c
index b4842e1b52aa..c80a3b966376 100644
--- a/stand/efi/libefi/efipart.c
+++ b/stand/efi/libefi/efipart.c
@@ -1292,7 +1292,7 @@ efiblk_memdisk_preload(void)
 		snprintf(value, sizeof(value), "0x%016x", start);
 		setenv(key, value, 1);
 		snprintf(key, sizeof(key), "hint.md.%d.len", i);
-		snprintf(value, sizeof(value), "0x%016x", end - start);
+		snprintf(value, sizeof(value), "%d", end - start + 1);
 		setenv(key, value, 1);
 	}
 }