linux-kernel - [PATCH v1 0/3] Fixes to L1D flushing (on top of linux-next and

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Message-ID: <20201117234934.25985-1-sblbir@amazon.com>
Date:   Wed, 18 Nov 2020 10:49:31 +1100
From:   Balbir Singh <sblbir@...zon.com>
To:     <tglx@...utronix.de>, <mingo@...hat.com>
CC:     <peterz@...radead.org>, <linux-kernel@...r.kernel.org>,
        <keescook@...omium.org>, Balbir Singh <sblbir@...zon.com>
Subject: [PATCH v1 0/3] Fixes to L1D flushing (on top of linux-next and

There were concerns with the current interface (checking for the state
of SMT of the core at opt-in time [1]). These patches change the
interface to send a SIGBUS to the task if

a. It opts into L1D flushing
b. Runs on a core with SMT enabled

There are also documentation fixes. I've tested the patches at my end,
but would appreciate a broad review of the change in functionality
and/or any recommended doc updates.


[1] http://lkml.iu.edu/hypermail/linux/kernel/2009.3/09310.html
[2] http://lkml.iu.edu/hypermail/linux/kernel/2009.3/09613.html

NOTE: For testing these patches, specifically the SIGBUS behaviour,
there needs to be contention on the CPU where the task that opts
into L1D flushing is running to see the SIGBUS being sent to it
(the deterministic bit is that if there is scope of data leak
the task will get killed)

Balbir Singh (3):
  x86/mm: change l1d flush runtime prctl behaviour
  Documentation: Update the new SIGBUS behaviour for tasks
  Documentation/l1d_flush: Fix up warning with labels

 .../admin-guide/hw-vuln/l1d_flush.rst         | 12 +++---
 arch/Kconfig                                  |  4 ++
 arch/x86/Kconfig                              |  1 +
 arch/x86/mm/tlb.c                             | 37 +++++++++++--------
 include/linux/sched.h                         | 10 +++++
 5 files changed, 42 insertions(+), 22 deletions(-)

-- 
2.17.1