Re: [PATCH 1/4] x86/fpu: Clear XSTATE_BV[i] in save state whenever XFD[i]=1

[Dave Hansen]

On 1/6/26 09:56, Jim Mattson wrote:
> Apologies. You're right. Though Intel is a bit coy, the only way to
> interpret that section of the SDM is to conclude that the AMX state in
> the CPU becomes undefined when XFD[18] is set.

I'll touch base with the folks that wrote that blurb. I'm a little
nervous to interpret that "software should not..." blurb as a full
architectural DANGER sign partly because it's in a "RECOMMENDATIONS FOR
SYSTEM SOFTWARE" section.

I'm _sure_ they discussed tying XFD[i] and XINUSE[i] together and there
was a good reason they did not.