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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     Laurent Dufour <ldufour@linux.ibm.com>, benh@kernel.crashing.org,
        paulus@samba.org, linuxppc-dev@lists.ozlabs.org
Cc:     nathanl@linux.ibm.com, cheloha@linux.ibm.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc/pseries: export LPAR security flavor in lparcfg
In-Reply-To: <20210304114240.54112-1-ldufour@linux.ibm.com>
References: <20210304114240.54112-1-ldufour@linux.ibm.com>
Date:   Fri, 05 Mar 2021 17:23:21 +1100
Message-ID: <871rcuruee.fsf@mpe.ellerman.id.au>
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Laurent Dufour <ldufour@linux.ibm.com> writes:
> This is helpful to read the security flavor from inside the LPAR.

We already have /sys/kernel/debug/powerpc/security_features.

Is that not sufficient?

> Export it like this in /proc/powerpc/lparcfg:
>
> $ grep security_flavor /proc/powerpc/lparcfg
> security_flavor=1
>
> Value means:
> 0 Speculative execution fully enabled
> 1 Speculative execution controls to mitigate user-to-kernel attacks
> 2 Speculative execution controls to mitigate user-to-kernel and
>   user-to-user side-channel attacks

Those strings come from the FSP help, but we have no guarantee it won't
mean something different in future.

cheers