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From:   Andy Lutomirski <luto@amacapital.net>
Mime-Version: 1.0 (1.0)
Subject: Re: [PATCH v10 6/6] x86/split_lock: Enable split lock detection by kernel parameter
Date:   Thu, 21 Nov 2019 14:24:21 -0800
Message-Id: <159DB397-87E2-435D-9F33-067FF9296ADC@amacapital.net>
References: <20191121215126.GA9075@agluck-desk2.amr.corp.intel.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        H Peter Anvin <hpa@zytor.com>,
        Ashok Raj <ashok.raj@intel.com>,
        Ravi V Shankar <ravi.v.shankar@intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
In-Reply-To: <20191121215126.GA9075@agluck-desk2.amr.corp.intel.com>
To:     "Luck, Tony" <tony.luck@intel.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


> On Nov 21, 2019, at 1:51 PM, Luck, Tony <tony.luck@intel.com> wrote:
>=20
> =EF=BB=BFOn Thu, Nov 21, 2019 at 02:15:22PM +0100, Peter Zijlstra wrote:
>> Also, just to remind everyone why we really want this. Split lock is a
>> potent, unprivileged, DoS vector.
>=20
> So how much do we "really want this"?
>=20
> It's been 543 days since the first version of this patch was
> posted. We've made exactly zero progress.
>=20
> Current cut down patch series is the foundation to move one
> small step towards getting this done.
>=20
> Almost all of what's in this set will be required in whatever
> final solution we want to end up with. Out of this:

Why don=E2=80=99t we beat it into shape and apply it, hidden behind BROKEN. T=
hen we can work on the rest of the patches and have a way to test them.

It would be really, really nice if we could pass this feature through to a V=
M. Can we?=