From: Jeremy Linton <jeremy.linton@arm.com>
To: Andre Przywara <andre.przywara@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, stefan.wahren@i2se.com,
Jonathan Corbet <corbet@lwn.net>,
mlangsdo@redhat.com, linux-doc@vger.kernel.org,
suzuki.poulose@arm.com, marc.zyngier@arm.com,
catalin.marinas@arm.com, julien.thierry@arm.com,
will.deacon@arm.com, linux-kernel@vger.kernel.org,
steven.price@arm.com, ykaukab@suse.de, dave.martin@arm.com,
shankerd@codeaurora.org
Subject: Re: [PATCH v4 01/12] Documentation: Document arm64 kpti control
Date: Wed, 6 Feb 2019 13:24:17 -0600 [thread overview]
Message-ID: <69fceac6-7e83-7b38-44fb-2c02245f51df@arm.com> (raw)
In-Reply-To: <20190130180247.15ab0577@donnerap.cambridge.arm.com>
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)
>>
>
next prev parent reply other threads:[~2019-02-06 19:24 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-25 18:06 [PATCH v4 00/12] arm64: add system vulnerability sysfs entries Jeremy Linton
2019-01-25 18:07 ` [PATCH v4 01/12] Documentation: Document arm64 kpti control Jeremy Linton
2019-01-30 18:02 ` Andre Przywara
2019-02-06 19:24 ` Jeremy Linton [this message]
2019-02-06 21:06 ` André Przywara
2019-01-31 17:58 ` Andre Przywara
2019-02-07 0:25 ` Jonathan Corbet
2019-01-25 18:07 ` [PATCH v4 02/12] arm64: Provide a command line to disable spectre_v2 mitigation Jeremy Linton
2019-01-30 18:03 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 03/12] arm64: Remove the ability to build a kernel without ssbd Jeremy Linton
2019-01-30 18:04 ` Andre Przywara
2019-02-15 18:20 ` Catalin Marinas
2019-02-15 18:54 ` Jeremy Linton
2019-01-25 18:07 ` [PATCH v4 04/12] arm64: remove the ability to build a kernel without hardened branch predictors Jeremy Linton
2019-01-30 18:04 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 05/12] arm64: remove the ability to build a kernel without kpti Jeremy Linton
2019-01-30 18:05 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 06/12] arm64: add sysfs vulnerability show for spectre v1 Jeremy Linton
2019-01-31 17:52 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 07/12] arm64: add sysfs vulnerability show for meltdown Jeremy Linton
2019-01-31 9:28 ` Julien Thierry
2019-01-31 21:48 ` Jeremy Linton
2019-01-31 17:54 ` Andre Przywara
2019-01-31 21:53 ` Jeremy Linton
2019-01-25 18:07 ` [PATCH v4 08/12] arm64: Advertise mitigation of Spectre-v2, or lack thereof Jeremy Linton
2019-01-31 17:54 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 09/12] arm64: Use firmware to detect CPUs that are not affected by Spectre-v2 Jeremy Linton
2019-01-31 17:55 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 10/12] arm64: add sysfs vulnerability show for spectre v2 Jeremy Linton
2019-01-31 17:55 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 11/12] arm64: add sysfs vulnerability show for speculative store bypass Jeremy Linton
2019-01-31 17:55 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 12/12] arm64: enable generic CPU vulnerabilites support Jeremy Linton
2019-01-31 17:56 ` Andre Przywara
2019-02-08 20:05 ` [PATCH v4 00/12] arm64: add system vulnerability sysfs entries Stefan Wahren
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