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From: Sean Christopherson <seanjc@google.com>
To: Jonathan Corbet <corbet@lwn.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,  Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org,  Peter Zijlstra <peterz@infradead.org>,
	Josh Poimboeuf <jpoimboe@kernel.org>
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	 Sean Christopherson <seanjc@google.com>,
	Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
	 Daniel Sneddon <daniel.sneddon@linux.intel.com>
Subject: [PATCH 0/3] x86/cpu: Fix SPECULATIVE_MITIGATION=n kernels
Date: Tue,  9 Apr 2024 10:51:04 -0700	[thread overview]
Message-ID: <20240409175108.1512861-1-seanjc@google.com> (raw)

Fix the handling of SPECULATION_MITIGATIONS=n so that it actually does
what it says it does: disable any and all mitigations.

And because I don't see a way to provide sane behavior for overriding
SPECULATION_MITIGATIONS=n at runtime, explicitly disallow doing so via
the "mitigations" kernel parameter, e.g. so that the user at least knows
that their system is still likely vulnerable to a variety of issues.

Sean Christopherson (3):
  x86/cpu: Actually turn off mitigations by default for
    SPECULATION_MITIGATIONS=n
  x86/cpu: Disable BHI mitigation by default when
    SPECULATION_MITIGATIONS=n
  x86/cpu: Ignore "mitigations" kernel parameter if
    SPECULATION_MITIGATIONS=n

 Documentation/admin-guide/kernel-parameters.txt |  3 +++
 arch/x86/Kconfig                                | 10 +++++++---
 arch/x86/kernel/cpu/bugs.c                      |  6 +++---
 kernel/cpu.c                                    |  5 ++++-
 4 files changed, 17 insertions(+), 7 deletions(-)


base-commit: 2c71fdf02a95b3dd425b42f28fd47fb2b1d22702
-- 
2.44.0.478.gd926399ef9-goog


             reply	other threads:[~2024-04-09 17:51 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-09 17:51 Sean Christopherson [this message]
2024-04-09 17:51 ` [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n Sean Christopherson
2024-04-13  1:53   ` Stephen Rothwell
2024-04-13  9:27     ` Michael Ellerman
2024-04-13  9:38       ` Michael Ellerman
2024-04-14 22:42         ` Stephen Rothwell
2024-04-15 11:16         ` Geert Uytterhoeven
2024-04-15 14:31           ` Sean Christopherson
2024-04-16 11:06             ` Michael Ellerman
2024-04-19 14:03             ` Will Deacon
2024-04-19 14:06               ` Sean Christopherson
2024-04-19 14:38                 ` Will Deacon
2024-04-15 11:13   ` Geert Uytterhoeven
2024-04-09 17:51 ` [PATCH 2/3] x86/cpu: Disable BHI mitigation by default when SPECULATION_MITIGATIONS=n Sean Christopherson
2024-04-09 17:51 ` [PATCH 3/3] x86/cpu: Ignore "mitigations" kernel parameter if SPECULATION_MITIGATIONS=n Sean Christopherson
2024-04-10 14:18   ` Ingo Molnar
2024-04-09 18:55 ` [PATCH 0/3] x86/cpu: Fix SPECULATIVE_MITIGATION=n kernels Daniel Sneddon

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