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References: <20220805214734.1937451-1-eugenis@google.com> <875yj1x0k0.wl-maz@kernel.org>
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From:   Evgenii Stepanov <eugenis@google.com>
Date:   Tue, 9 Aug 2022 09:41:28 -0700
Message-ID: <CAFKCwrjVaOdrGktxVHLCDPyJSRjZ0B3FHTGsb3PXMULL=dw9rA@mail.gmail.com>
Subject: Re: [PATCH] mte: Follow arm64.nomte override in MMU setup.
To:     Marc Zyngier <maz@kernel.org>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Peter Collingbourne <pcc@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Tue, Aug 9, 2022 at 1:50 AM Marc Zyngier <maz@kernel.org> wrote:
> How comes such memory is being used? How comes it is in the linear
> map?
>
> arm64.nomte is affecting the use of MTE feature on the platform. It
> doesn't guard the use of a MTE carve-out, and doesn't allow it to be
> used in any shape or form.
>
> To use this memory, you should remove the MTE configuration
> altogether, as you cannot infer what the CPU is doing with it.

This can be used to enable MTE in TZ but not in the NS memory.