Re: [kernel-hardening] Re: [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode

From: Richard Weinberger
Date: Sun May 07 2017 - 18:07:15 EST


On Fri, May 5, 2017 at 9:40 AM, Daniel Gruss
<daniel.gruss@xxxxxxxxxxxxxx> wrote:
> I'm sure the overhead on older systems is larger than on recent systems.

Just did a quick test on my main KVM host, a 8 core Intel(R) Xeon(R)
CPU E3-1240 V2.
KVM guests are 4.10 w/o CONFIG_KAISER and kvmconfig without CONFIG_PARAVIRT.
Building a defconfig kernel within that guests is about 10% slower
is enabled.

Is this expected?
If it helps I can redo the same test also on bare metal.