Re: [PATCH] l1tf: drop the swap storage limit restriction when l1tf=off

From: Michal Hocko
Date: Mon Nov 19 2018 - 08:51:54 EST


On Mon 19-11-18 14:36:32, Jiri Kosina wrote:
> On Wed, 14 Nov 2018, Michal Hocko wrote:
>
> > > > + It also drops the swap size and available
> > > > + RAM limit restriction.
> > >
> > > Minor nit: I think this should explicitly mention that those two things
> > > are related to bare metal mitigation, to avoid any confusion (as otherwise
> > > the l1tf cmdline parameter is purely about hypervisor mitigations).
> >
> > Do you have any specific wording in mind?
> >
> > It also drops the swap size and available RAM limit restrictions on both
> > hypervisor and bare metal.
> >
> > Sounds better?
> >
> > > With that
> > >
> > > Acked-by: Jiri Kosina <jkosina@xxxxxxx>
> >
> > Thanks!
>
> Yes, I think that makes it absolutely clear. Thanks,

OK. Here is the incremental diff on top of the patch. I will fold and
repost later this week. I assume people are still catching up after LPC
and I do not want to spam them even more.

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a54f2bd39e77..c5aa4b4a797d 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2096,7 +2096,8 @@
Disables hypervisor mitigations and doesn't
emit any warnings.
It also drops the swap size and available
- RAM limit restriction.
+ RAM limit restriction on both hypervisor and
+ bare metal.

Default is 'flush'.

diff --git a/Documentation/admin-guide/l1tf.rst b/Documentation/admin-guide/l1tf.rst
index b00464a9c09c..2e65e6cb033e 100644
--- a/Documentation/admin-guide/l1tf.rst
+++ b/Documentation/admin-guide/l1tf.rst
@@ -405,7 +405,8 @@ The kernel command line allows to control the L1TF mitigations at boot

off Disables hypervisor mitigations and doesn't emit any
warnings.
- It also drops the swap size and available RAM limit restrictions.
+ It also drops the swap size and available RAM limit restrictions
+ on both hypervisor and bare metal.

============ =============================================================

--
Michal Hocko
SUSE Labs