Re: [PATCH v2 0/9] x86/xsaves: Fix XSAVES known issues

[Dave Hansen]

On 02/25/2016 12:26 PM, Yu-cheng Yu wrote:
> Patch 9 re-enables XSAVES.

Could we also add one more thing to this: A big, fat warning that
supervisor states are not supported?  We might get that from an eventual
use of xfeature_uncompacted_offset(), but we need something that's very
clear.

I just don't want somebody coming along and shoving a supervisor state
in to XCR0 and expecting it to work just because we have XSAVES support
itself.  That might happen in-tree or out-of-tree as things get prototyped.