Messages in this thread | | | Subject | Re: [PATCH v4 01/12] Documentation: Document arm64 kpti control | From | Jeremy Linton <> | Date | Wed, 6 Feb 2019 13:24:17 -0600 |
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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) >> >
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