Re: [PATCH] x86/tsx: fix KVM guest live migration for tsx=on

From: Dave Hansen
Date: Tue Apr 12 2022 - 11:55:00 EST


On 4/12/22 06:36, Jon Kohler wrote:
> So my theory here is to extend the logical effort of the microcode driven
> automatic disablement as well as the tsx=auto automatic disablement and
> have tsx=on force abort all transactions on X86_BUG_TAA SKUs, but leave
> the CPU features enumerated to maintain live migration.
>
> This would still leave TSX totally good on Ice Lake / non-buggy systems.
>
> If it would help, I'm working up an RFC patch, and we could discuss there?

Sure. But, it sounds like you really want a new tdx=something rather
than to muck with tsx=on behavior. Surely someone else will come along
and complain that we broke their TDX setup if we change its behavior.

Maybe you should just pay the one-time cost and move your whole fleet
over to tsx=off if you truly believe nobody is using it.