Re: Candidate Linux ABI for Intel AMX and hypothetical new related features

On Fri, Mar 26, 2021 at 11:39:18PM -0400, Len Brown wrote:

Hi Andy,

Say a mainline links with a math library that uses AMX without the
knowledge of the mainline.

What does this mean?  What happened to the context here?

Say the mainline is also linked with a userspace threading library
that thinks it has a concept of XSAVE area size.

How can the kernel (what I think you mean by "mainline" here) be linked
with a userspace library at all?

Wouldn't the change in XCR0, resulting in XSAVE size change, risk
confusing the threading library?

Shouldn't that be the job of the kernel and not userspace?

totally confused,

greg k-h