[stable:PATCH v4.19.267 0/2] arm64: errata: Spectre-BHB fixes

From: James Morse <james.morse@arm.com>
To: stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	James Morse <james.morse@arm.com>
Subject: [stable:PATCH v4.19.267 0/2] arm64: errata: Spectre-BHB fixes
Date: Wed, 30 Nov 2022 18:29:05 +0000	[thread overview]
Message-ID: <20221130182907.739150-1-james.morse@arm.com> (raw)

Hello!

The first patch fixes an issue reported by Sami, where linux panic()s
when bringing secondary CPUs online. The problem was the Spectre
workarounds trying to allocate a new slot for mitigating KVM when
those pages are no longer writeable.

While debugging that issue, I spotted the Spectre-BHB KVM mitigation was
over-riding the Spectre-v2 KVM Mitigation. It's supposed to happen the
other way round.

The backports aren't the same as mainline because the spectre mitigation code
was totally rewritten for v5.10, and prior to that the KVM infrastructure
is very different.

Thanks,

James Morse (2):
  arm64: Fix panic() when Spectre-v2 causes Spectre-BHB to re-allocate
    KVM vectors
  arm64: errata: Fix KVM Spectre-v2 mitigation selection for
    Cortex-A57/A72

 arch/arm64/kernel/cpu_errata.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

-- 
2.30.2

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