Re: [PATCH] x86/speculation: Avoid LFENCE in FILL_RETURN_BUFFER on CPUs that lack it

[Peter Zijlstra]

On Fri, Aug 19, 2022 at 01:38:27PM +0200, Ben Hutchings wrote:

> So that puts the whole __FILL_RETURN_BUFFER inside an alternative, and
> we can't have nested alternatives.  That's unfortunate.

Well, both alternatives end with the LFENCE instruction, so I could pull
it out and do two consequtive ALTs, but unrolling the loop for i386 is
a better solution in that the sequence, while larger, removes the need
for the LFENCE.