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Date:   Thu, 3 Jan 2019 10:38:58 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Jeremy Linton <jeremy.linton@arm.com>
Cc:     linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com,
        will.deacon@arm.com, marc.zyngier@arm.com, suzuki.poulose@arm.com,
        dave.martin@arm.com, shankerd@codeaurora.org, mark.rutland@arm.com,
        linux-kernel@vger.kernel.org, ykaukab@suse.de,
        julien.thierry@arm.com, mlangsdo@redhat.com, steven.price@arm.com,
        Thomas Gleixner <tglx@linutronix.de>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Borislav Petkov <bp@alien8.de>,
        David Woodhouse <dwmw@amazon.co.uk>
Subject: Re: [PATCH v2 1/7] sysfs/cpu: Add "Unknown" vulnerability state
Message-ID: <20190103093858.GA10794@kroah.com>
References: <20190103004921.1928921-1-jeremy.linton@arm.com>
 <20190103004921.1928921-2-jeremy.linton@arm.com>
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On Wed, Jan 02, 2019 at 06:49:15PM -0600, Jeremy Linton wrote:
> There is a lot of variation in the Arm ecosystem. Because of this,
> there exist possible cases where the kernel cannot authoritatively
> determine if a machine is vulnerable.

Really?  Why not?  What keeps you from "knowing" this?  Can't the
developer of the chip tell you?

> Rather than guess the vulnerability status in cases where
> the mitigation is disabled or the firmware isn't responding
> correctly, we need to display an "Unknown" state.

Shouldn't "Unknown" really be the same thing as "Vulnerable"?  A user
should treat it the same way, "Unknown" makes it feel like "maybe I can
just ignore this and hope I really am safe", which is not a good idea at
all.

thanks,

greg k-h