Re: [PATCH 01/17] x86: spec_ctrl: fix SPEC_CTRL initialization after kexec

From: Paolo Bonzini
Date: Mon Sep 23 2019 - 06:22:28 EST


On 20/09/19 23:24, Andrea Arcangeli wrote:
> We can't assume the SPEC_CTRL msr is zero at boot because it could be
> left enabled by a previous kernel booted with
> spec_store_bypass_disable=on.
>
> Without this fix a boot with spec_store_bypass_disable=on followed by
> a kexec boot with spec_store_bypass_disable=off would erroneously and
> unexpectedly leave bit 2 set in SPEC_CTRL.
>
> Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>

Can you send this out separately, so that Thomas et al. can pick it up
as a bug fix?

Thanks,

Paolo