Legacy VM86 support

configname: CONFIG_X86_LEGACY_VM86

Linux Kernel Configuration
└─>Processor type and features
└─>Legacy VM86 support
In linux kernel since version 4.1 (release Date: 2015-06-21)  
This option allows user programs to put the CPU into V8086
mode, which is an 80286-era approximation of 16-bit real mode.

Some very old versions of X and/or vbetool require this option
for user mode setting. Similarly, DOSEMU will use it if
available to accelerate real mode DOS programs. However, any
recent version of DOSEMU, X, or vbetool should be fully
functional even without kernel VM86 support, as they will all
fall back to software emulation. Nevertheless, if you are using
a 16-bit DOS program where 16-bit performance matters, vm86
mode might be faster than emulation and you might want to
enable this option.

Note that any app that works on a 64-bit kernel is unlikely to
need this option, as 64-bit kernels don't, and can't, support
V8086 mode. This option is also unrelated to 16-bit protected
mode and is not needed to run most 16-bit programs under Wine.

Enabling this option increases the complexity of the kernel
and slows down exception handling a tiny bit.

If unsure, say N here.