Constant SMBIOS_STRING_MAX_LEN 

pub const SMBIOS_STRING_MAX_LEN: usize = _; // 32usize

Maximum number of bytes of a variable-length SMBIOS string (e.g. the system serial number) that the config port can deliver to the BIOS ROM.

The port returns each string in eight 4-byte chunks (read_count % 8), so any bytes beyond this are never read by the guest and would be silently truncated.