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From: Linus Walleij <linus.walleij@linaro.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 0/2] ARM/decompressor: deal with disabled CP15 barrier instructions
Date: Wed, 13 Nov 2019 14:58:38 +0100	[thread overview]
Message-ID: <CACRpkdbaGd9rQqg641zZ_8-YL8yyTN8RkkVggQNb=fZ-1+NPdA@mail.gmail.com> (raw)
In-Reply-To: <20191106094219.24365-1-ardb@kernel.org>

On Wed, Nov 6, 2019 at 10:42 AM Ard Biesheuvel <ardb@kernel.org> wrote:

> While trying to test my v4.4 backport of the firmware/hypervisor based spectre
> v1/v2 mitigations for 32-bit ARM, I noticed that KVM/qemu failed to boot my
> kernel while it booted fine under TCG emulation.
>
> As it turns out, KVM/qemu may instantiate the VCPU with support for CP15
> barrier instructions disabled, causing them to UNDEF and crash the
> decompressor.
>
> I already fixed the same issue for UEFI boot, but since v4.4 does not support
> that, I only noticed now that this is an issue for bare metal as well.
>
> Cc: Russell King <rmk+kernel@armlinux.org.uk>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Marc Zyngier <maz@kernel.org>

FWIW:
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Looking at patches for stable is a bit like cleaning the sink in the bathroom,
seems OK at first but after a while you get scared by the stuff that comes
up.

Yours,
Linus Walleij

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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2019-11-13 13:59 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-06  9:42 [PATCH 0/2] ARM/decompressor: deal with disabled CP15 barrier instructions Ard Biesheuvel
2019-11-06  9:42 ` [PATCH 1/2] ARM/decompressor: avoid CP15 barrier instructions in v7 cache setup code Ard Biesheuvel
2019-11-06  9:42 ` [PATCH 2/2] Revert "ARM: 8857/1: efi: enable CP15 DMB instructions before cleaning the cache" Ard Biesheuvel
2019-11-13 13:58 ` Linus Walleij [this message]
2019-11-14  9:54   ` [PATCH 0/2] ARM/decompressor: deal with disabled CP15 barrier instructions Ard Biesheuvel

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