lkml.org 
[lkml]   [2019]   [Feb]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v4 01/12] Documentation: Document arm64 kpti control
From
Date
Hi,


I just realized I replied to this off-list.

On 01/30/2019 12:02 PM, Andre Przywara wrote:
> On Fri, 25 Jan 2019 12:07:00 -0600
> Jeremy Linton <jeremy.linton@arm.com> wrote:
>
> Hi,
>
>> For a while Arm64 has been capable of force enabling
>> or disabling the kpti mitigations. Lets make sure the
>> documentation reflects that.
>>
>> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
>> Cc: Jonathan Corbet <corbet@lwn.net>
>> Cc: linux-doc@vger.kernel.org
>> ---
>> Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt
>> b/Documentation/admin-guide/kernel-parameters.txt index
>> b799bcf67d7b..9475f02c79da 100644 ---
>> a/Documentation/admin-guide/kernel-parameters.txt +++
>> b/Documentation/admin-guide/kernel-parameters.txt @@ -1982,6 +1982,12
>> @@ Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
>> the default is off.
>>
>> + kpti= [ARM64] Control page table isolation of
>> user
>> + and kernel address spaces.
>> + Default: enabled on cores which need
>> mitigation.
>
> Would this be a good place to mention that we enable it when
> CONFIG_RANDOMIZE_BASE is enabled and we have a valid kaslr_offset? I
> found this somewhat surprising, also it's unrelated to the
> vulnerability.

Maybe, but I tend to think since this command line forces it on/off
regardless of RANDOMIZE_BASE, that a better place to mention that
RANDOMIZE_BASE forces kpti on is the Kconfig option.

BTW: Thanks for reviewing this.


>
> Cheers,
> Andre
>
>> + 0: force disabled
>> + 1: force enabled
>> +
>> kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled
>> MSRs. Default is 0 (don't ignore, but inject #GP)
>>
>

\
 
 \ /
  Last update: 2019-02-06 20:25    [W:0.062 / U:28.676 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site