From: Andrea Arcangeli <aarcange@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Josep Torrellas <torrella@illinois.edu>,
Tobin Feldman-Fitzthum <tobin@ibm.com>,
Hubertus Franke <frankeh@us.ibm.com>,
Jack Chen <jianyan2@illinois.edu>,
Giuseppe Scrivano <gscrivan@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
YiFei Zhu <yifeifz2@illinois.edu>,
Waiman Long <longman@redhat.com>, Tianyin Xu <tyxu@illinois.edu>,
Jann Horn <jannh@google.com>, Jiri Kosina <jikos@kernel.org>,
Valentin Rothberg <vrothber@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Will Drewry <wad@chromium.org>,
Linux Containers <containers@lists.linux-foundation.org>,
kernel list <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
David Laight <David.Laight@aculab.com>, bpf <bpf@vger.kernel.org>
Subject: [PATCH 1/1] x86: deduplicate the spectre_v2_user documentation
Date: Wed, 4 Nov 2020 19:14:06 -0500 [thread overview]
Message-ID: <20201105001406.13005-2-aarcange@redhat.com> (raw)
In-Reply-To: <20201105001406.13005-1-aarcange@redhat.com>
This would need updating to make prctl be the new default, but it's
simpler to delete it and refer to the dup.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
---
Documentation/admin-guide/hw-vuln/spectre.rst | 51 +------------------
1 file changed, 2 insertions(+), 49 deletions(-)
diff --git a/Documentation/admin-guide/hw-vuln/spectre.rst b/Documentation/admin-guide/hw-vuln/spectre.rst
index 19b897cb1d45..ab7d402c1677 100644
--- a/Documentation/admin-guide/hw-vuln/spectre.rst
+++ b/Documentation/admin-guide/hw-vuln/spectre.rst
@@ -593,61 +593,14 @@ kernel command line.
Not specifying this option is equivalent to
spectre_v2=auto.
-For user space mitigation:
-
- spectre_v2_user=
-
- [X86] Control mitigation of Spectre variant 2
- (indirect branch speculation) vulnerability between
- user space tasks
-
- on
- Unconditionally enable mitigations. Is
- enforced by spectre_v2=on
-
- off
- Unconditionally disable mitigations. Is
- enforced by spectre_v2=off
-
- prctl
- Indirect branch speculation is enabled,
- but mitigation can be enabled via prctl
- per thread. The mitigation control state
- is inherited on fork.
-
- prctl,ibpb
- Like "prctl" above, but only STIBP is
- controlled per thread. IBPB is issued
- always when switching between different user
- space processes.
-
- seccomp
- Same as "prctl" above, but all seccomp
- threads will enable the mitigation unless
- they explicitly opt out.
-
- seccomp,ibpb
- Like "seccomp" above, but only STIBP is
- controlled per thread. IBPB is issued
- always when switching between different
- user space processes.
-
- auto
- Kernel selects the mitigation depending on
- the available CPU features and vulnerability.
-
- Default mitigation:
- If CONFIG_SECCOMP=y then "seccomp", otherwise "prctl"
-
- Not specifying this option is equivalent to
- spectre_v2_user=auto.
-
In general the kernel by default selects
reasonable mitigations for the current CPU. To
disable Spectre variant 2 mitigations, boot with
spectre_v2=off. Spectre variant 1 mitigations
cannot be disabled.
+For spectre_v2_user see :doc:`/admin-guide/kernel-parameters`.
+
Mitigation selection guide
--------------------------
_______________________________________________
Containers mailing list
Containers@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/containers
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>,
Linux Containers <containers@lists.linux-foundation.org>,
YiFei Zhu <yifeifz2@illinois.edu>, bpf <bpf@vger.kernel.org>,
kernel list <linux-kernel@vger.kernel.org>,
Aleksa Sarai <cyphar@cyphar.com>,
Andy Lutomirski <luto@amacapital.net>,
David Laight <David.Laight@aculab.com>,
Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
Giuseppe Scrivano <gscrivan@redhat.com>,
Hubertus Franke <frankeh@us.ibm.com>,
Jack Chen <jianyan2@illinois.edu>, Jann Horn <jannh@google.com>,
Josep Torrellas <torrella@illinois.edu>,
Tianyin Xu <tyxu@illinois.edu>,
Tobin Feldman-Fitzthum <tobin@ibm.com>,
Tycho Andersen <tycho@tycho.pizza>,
Valentin Rothberg <vrothber@redhat.com>,
Will Drewry <wad@chromium.org>, Jiri Kosina <jikos@kernel.org>,
Waiman Long <longman@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Andi Kleen <ak@linux.intel.com>
Subject: [PATCH 1/1] x86: deduplicate the spectre_v2_user documentation
Date: Wed, 4 Nov 2020 19:14:06 -0500 [thread overview]
Message-ID: <20201105001406.13005-2-aarcange@redhat.com> (raw)
In-Reply-To: <20201105001406.13005-1-aarcange@redhat.com>
This would need updating to make prctl be the new default, but it's
simpler to delete it and refer to the dup.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
---
Documentation/admin-guide/hw-vuln/spectre.rst | 51 +------------------
1 file changed, 2 insertions(+), 49 deletions(-)
diff --git a/Documentation/admin-guide/hw-vuln/spectre.rst b/Documentation/admin-guide/hw-vuln/spectre.rst
index 19b897cb1d45..ab7d402c1677 100644
--- a/Documentation/admin-guide/hw-vuln/spectre.rst
+++ b/Documentation/admin-guide/hw-vuln/spectre.rst
@@ -593,61 +593,14 @@ kernel command line.
Not specifying this option is equivalent to
spectre_v2=auto.
-For user space mitigation:
-
- spectre_v2_user=
-
- [X86] Control mitigation of Spectre variant 2
- (indirect branch speculation) vulnerability between
- user space tasks
-
- on
- Unconditionally enable mitigations. Is
- enforced by spectre_v2=on
-
- off
- Unconditionally disable mitigations. Is
- enforced by spectre_v2=off
-
- prctl
- Indirect branch speculation is enabled,
- but mitigation can be enabled via prctl
- per thread. The mitigation control state
- is inherited on fork.
-
- prctl,ibpb
- Like "prctl" above, but only STIBP is
- controlled per thread. IBPB is issued
- always when switching between different user
- space processes.
-
- seccomp
- Same as "prctl" above, but all seccomp
- threads will enable the mitigation unless
- they explicitly opt out.
-
- seccomp,ibpb
- Like "seccomp" above, but only STIBP is
- controlled per thread. IBPB is issued
- always when switching between different
- user space processes.
-
- auto
- Kernel selects the mitigation depending on
- the available CPU features and vulnerability.
-
- Default mitigation:
- If CONFIG_SECCOMP=y then "seccomp", otherwise "prctl"
-
- Not specifying this option is equivalent to
- spectre_v2_user=auto.
-
In general the kernel by default selects
reasonable mitigations for the current CPU. To
disable Spectre variant 2 mitigations, boot with
spectre_v2=off. Spectre variant 1 mitigations
cannot be disabled.
+For spectre_v2_user see :doc:`/admin-guide/kernel-parameters`.
+
Mitigation selection guide
--------------------------
next prev parent reply other threads:[~2020-11-05 0:14 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-04 21:57 RFC: default to spec_store_bypass_disable=prctl spectre_v2_user=prctl Andrea Arcangeli
2020-11-04 21:57 ` Andrea Arcangeli
2020-11-04 22:14 ` Kees Cook
2020-11-04 22:14 ` Kees Cook
2020-11-04 23:22 ` Thomas Gleixner
2020-11-04 23:22 ` Thomas Gleixner
2020-11-04 23:40 ` Andrea Arcangeli
2020-11-04 23:40 ` Andrea Arcangeli
2020-11-05 0:14 ` [PATCH 0/1] x86: deduplicate the spectre_v2_user documentation Andrea Arcangeli
2020-11-05 0:14 ` Andrea Arcangeli
2020-11-05 0:14 ` Andrea Arcangeli [this message]
2020-11-05 0:14 ` [PATCH 1/1] " Andrea Arcangeli
2021-09-11 21:13 ` Kees Cook
2020-11-04 23:50 ` [PATCH 1/1] x86: change default to spec_store_bypass_disable=prctl spectre_v2_user=prctl Andrea Arcangeli
2020-11-04 23:50 ` Andrea Arcangeli
2021-09-11 21:13 ` Kees Cook
2021-09-12 2:01 ` Josh Poimboeuf
2021-10-04 17:54 ` Josh Poimboeuf
2021-10-04 19:14 ` Kees Cook
2021-09-12 23:14 ` Waiman Long
2021-07-10 18:05 ` RFC: " Jim Newsome
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