linux-kernel - [PATCH 0/3] x86/cpu: Fix SPECULATIVE

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Message-ID: <20240409175108.1512861-1-seanjc@google.com>
Date: Tue,  9 Apr 2024 10:51:04 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Jonathan Corbet <corbet@....net>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, 
	Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	Peter Zijlstra <peterz@...radead.org>, Josh Poimboeuf <jpoimboe@...nel.org>
Cc: linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Sean Christopherson <seanjc@...gle.com>, Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>, 
	Daniel Sneddon <daniel.sneddon@...ux.intel.com>
Subject: [PATCH 0/3] x86/cpu: Fix SPECULATIVE_MITIGATION=n kernels

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