LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jiri Kosina <jkosina@suse.cz>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	David Woodhouse <dwmw@amazon.co.uk>,
	Andi Kleen <ak@linux.intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Casey Schaufler <casey.schaufler@intel.com>,
	Asit Mallick <asit.k.mallick@intel.com>,
	Arjan van de Ven <arjan@linux.intel.com>,
	Jon Masters <jcm@redhat.com>, Waiman Long <longman9394@gmail.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	Dave Stewart <david.c.stewart@intel.com>,
	Kees Cook <keescook@chromium.org>
Subject: [patch 00/24] x86/speculation: Remedy the STIBP/IBPB overhead
Date: Wed, 21 Nov 2018 21:14:30 +0100
Message-ID: <20181121201430.559770965@linutronix.de> (raw)

This is based on Tim Chen's V5 patch series. The following changes have
been made:

   - Control STIPB evaluation with a single static key

   - Move IBPB out from switch_mm() into switch_to() and control the
     always and the conditional mode with static keys.

     The mainline implementation is wrong in a few aspects, e.g. it fails
     to protect tasks within the same process, which breaks
     sandboxing. That same process optimization was the sole reason to have
     it in switch_mm().

     The new always mode is just issuing the barrier unconditionally when
     switching to a user task, but that also leaves STIPB always on. So
     really paranoid people get the highest possible protection and the
     highest overhead.

     The conditional mode issues the barrier when a task which is mitigated
     is scheduling out or scheduling in. That is required to support proper
     sandboxing.

   - Remove the ptrace_may_access_sched() code as it's unused now. It was
     ugly anyway and would have given people ideas how to slow down
     switch_mm() some more.

   - Rename TIF_STIPB to TIF_SPEC_IB because it controls both STIBP and
     IBPB.

   - Fix all the corner cases vs. UP and SMT disabled.

   - Limit the overhead when conditional STIPB is not enabled so
     switch_to_xtra() is not invoked for nothing when the TIF bit would
     trigger the entry and nothing else is to do. That can happen when SMT
     is off and a task has the TIF bit set. On UP STIPB is never enabled.

   - Dropped the dumpable part

TODO: Write documentation

It's avaiable from git:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git WIP.x86/pti

It's based on the x86/pti branch unfortunately, which contains the removal
of the minimal asm retpoline hackery. I noticed too late. If the minimal
asm stuff should not be backported it's trivial to rebase that series on
Linus tree.

Thanks,

	tglx




             reply index

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-21 20:14 Thomas Gleixner [this message]
2018-11-21 20:14 ` [patch 01/24] x86/speculation: Update the TIF_SSBD comment Thomas Gleixner
2018-11-21 20:28   ` Linus Torvalds
2018-11-21 20:30     ` Thomas Gleixner
2018-11-21 20:33     ` Linus Torvalds
2018-11-21 22:48       ` Thomas Gleixner
2018-11-21 22:53         ` Borislav Petkov
2018-11-21 22:55           ` Thomas Gleixner
2018-11-21 22:55           ` Arjan van de Ven
2018-11-21 22:56             ` Borislav Petkov
2018-11-21 23:07               ` Borislav Petkov
2018-11-21 23:04         ` Josh Poimboeuf
2018-11-21 23:08           ` Borislav Petkov
2018-11-22 17:30             ` Josh Poimboeuf
2018-11-22 17:52               ` Borislav Petkov
2018-11-22 21:17                 ` Thomas Gleixner
2018-11-21 20:14 ` [patch 02/24] x86/speculation: Clean up spectre_v2_parse_cmdline() Thomas Gleixner
2018-11-21 20:14 ` [patch 03/24] x86/speculation: Remove unnecessary ret variable in cpu_show_common() Thomas Gleixner
2018-11-21 20:14 ` [patch 04/24] x86/speculation: Reorganize cpu_show_common() Thomas Gleixner
2018-11-21 20:14 ` [patch 05/24] x86/speculation: Disable STIBP when enhanced IBRS is in use Thomas Gleixner
2018-11-21 20:33   ` Borislav Petkov
2018-11-21 20:36     ` Thomas Gleixner
2018-11-21 22:01       ` Thomas Gleixner
2018-11-21 20:14 ` [patch 06/24] x86/speculation: Rename SSBD update functions Thomas Gleixner
2018-11-21 20:14 ` [patch 07/24] x86/speculation: Reorganize speculation control MSRs update Thomas Gleixner
2018-11-21 20:14 ` [patch 08/24] sched/smt: Make sched_smt_present track topology Thomas Gleixner
2018-11-21 20:14 ` [patch 09/24] x86/Kconfig: Select SCHED_SMT if SMP enabled Thomas Gleixner
2018-11-21 20:14 ` [patch 10/24] sched/smt: Expose sched_smt_present static key Thomas Gleixner
2018-11-21 20:41   ` Thomas Gleixner
2018-11-21 20:14 ` [patch 11/24] x86/speculation: Rework SMT state change Thomas Gleixner
2018-11-21 20:14 ` [patch 12/24] x86/l1tf: Show actual SMT state Thomas Gleixner
2018-11-21 20:14 ` [patch 13/24] x86/speculation: Reorder the spec_v2 code Thomas Gleixner
2018-11-21 20:14 ` [patch 14/24] x86/speculation: Unify conditional spectre v2 print functions Thomas Gleixner
2018-11-22  7:59   ` Ingo Molnar
2018-11-21 20:14 ` [patch 15/24] x86/speculation: Add command line control for indirect branch speculation Thomas Gleixner
2018-11-21 23:43   ` Borislav Petkov
2018-11-22  8:14     ` Thomas Gleixner
2018-11-22  9:07       ` Thomas Gleixner
2018-11-22  9:18       ` Peter Zijlstra
2018-11-22 10:10         ` Borislav Petkov
2018-11-22 10:48           ` Thomas Gleixner
2018-11-21 20:14 ` [patch 16/24] x86/speculation: Prepare for per task indirect branch speculation control Thomas Gleixner
2018-11-22  7:57   ` Ingo Molnar
2018-11-21 20:14 ` [patch 17/24] x86/speculation: Move IBPB control out of switch_mm() Thomas Gleixner
2018-11-22  0:01   ` Andi Kleen
2018-11-22  7:42     ` Jiri Kosina
2018-11-22  9:18       ` Thomas Gleixner
2018-11-22  1:40   ` Tim Chen
2018-11-22  7:52   ` Ingo Molnar
2018-11-22 22:29     ` Thomas Gleixner
2018-11-21 20:14 ` [patch 18/24] x86/speculation: Avoid __switch_to_xtra() calls Thomas Gleixner
2018-11-22  1:23   ` Tim Chen
2018-11-22  7:44     ` Ingo Molnar
2018-11-21 20:14 ` [patch 19/24] ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS Thomas Gleixner
2018-11-21 20:14 ` [patch 20/24] x86/speculation: Split out TIF update Thomas Gleixner
2018-11-22  2:13   ` Tim Chen
2018-11-22 23:00     ` Thomas Gleixner
2018-11-23  7:37       ` Ingo Molnar
2018-11-26 18:35         ` Tim Chen
2018-11-26 21:55           ` Thomas Gleixner
2018-11-27  7:05             ` Jiri Kosina
2018-11-27  7:13               ` Thomas Gleixner
2018-11-27  7:30                 ` Jiri Kosina
2018-11-27 12:52                   ` Jiri Kosina
2018-11-27 13:18                     ` Jiri Kosina
2018-11-27 21:57                     ` Thomas Gleixner
2018-11-27 22:07                       ` Jiri Kosina
2018-11-27 22:20                         ` Jiri Kosina
2018-11-27 22:36                         ` Thomas Gleixner
2018-11-28  1:50                           ` Tim Chen
2018-11-28 10:43                             ` Thomas Gleixner
2018-11-28  6:05                           ` Jiri Kosina
2018-11-28 14:33                       ` [tip:x86/pti] x86/speculation: Prevent stale SPEC_CTRL msr content tip-bot for Thomas Gleixner
2018-11-22  7:43   ` [patch 20/24] x86/speculation: Split out TIF update Ingo Molnar
2018-11-22 23:04     ` Thomas Gleixner
2018-11-23  7:37       ` Ingo Molnar
2018-11-21 20:14 ` [patch 21/24] x86/speculation: Prepare arch_smt_update() for PRCTL mode Thomas Gleixner
2018-11-22  7:34   ` Ingo Molnar
2018-11-22 23:17     ` Thomas Gleixner
2018-11-22 23:28       ` Jiri Kosina
2018-11-21 20:14 ` [patch 22/24] x86/speculation: Create PRCTL interface to restrict indirect branch speculation Thomas Gleixner
2018-11-22  7:10   ` Ingo Molnar
2018-11-22  9:03   ` Peter Zijlstra
2018-11-22  9:08     ` Thomas Gleixner
2018-11-22 12:26   ` Borislav Petkov
2018-11-22 12:33     ` Peter Zijlstra
2018-11-21 20:14 ` [patch 23/24] x86/speculation: Enable PRCTL mode for spectre_v2_app2app Thomas Gleixner
2018-11-22  7:17   ` Ingo Molnar
2018-11-21 20:14 ` [patch 24/24] x86/speculation: Add seccomp Spectre v2 app to app protection mode Thomas Gleixner
2018-11-22  2:24   ` Tim Chen
2018-11-22  7:26   ` Ingo Molnar
2018-11-22 23:45     ` Thomas Gleixner
2018-11-21 23:48 ` [patch 00/24] x86/speculation: Remedy the STIBP/IBPB overhead Tim Chen
2018-11-22  9:55   ` Thomas Gleixner
2018-11-22  9:45 ` Peter Zijlstra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20181121201430.559770965@linutronix.de \
    --to=tglx@linutronix.de \
    --cc=aarcange@redhat.com \
    --cc=ak@linux.intel.com \
    --cc=arjan@linux.intel.com \
    --cc=asit.k.mallick@intel.com \
    --cc=casey.schaufler@intel.com \
    --cc=dave.hansen@intel.com \
    --cc=david.c.stewart@intel.com \
    --cc=dwmw@amazon.co.uk \
    --cc=gregkh@linuxfoundation.org \
    --cc=jcm@redhat.com \
    --cc=jkosina@suse.cz \
    --cc=jpoimboe@redhat.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=longman9394@gmail.com \
    --cc=luto@kernel.org \
    --cc=peterz@infradead.org \
    --cc=thomas.lendacky@amd.com \
    --cc=torvalds@linux-foundation.org \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git