Re: [PATCH v4 10/10] x86/xsaves: Re-enable XSAVES

From: Dave Hansen
Date: Wed May 04 2016 - 18:46:53 EST

On 05/04/2016 03:41 PM, Dave Hansen wrote:
> But, since we *always* call XSAVES with an instruction mask of -1 and
> end up with a requested feature bitmap (RFBM) equal to XCR0, I think we
> can do a shortcut because we'll practically *always* have an
> xcomp_bv==RFBM==XCR0, which means that all (present) components will
> always have an address.

Actually, we depend on that anyway. xstate_comp_offsets[] is completely
bogus if we don't have xcomp_bv==RFBM==XCR0.

Perhaps we need to add those checks anyway.