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Subject: Re: [RFC 00/10] Process-local memory allocations for hiding KVM secrets
From:   Andy Lutomirski <luto@amacapital.net>
In-Reply-To: <3cd533c1-3f18-a84f-fbb2-264751ed3eeb@intel.com>
Date:   Wed, 12 Jun 2019 13:56:31 -0700
Cc:     Marius Hillenbrand <mhillenb@amazon.de>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com,
        linux-mm@kvack.org, Alexander Graf <graf@amazon.de>,
        David Woodhouse <dwmw@amazon.co.uk>,
        the arch/x86 maintainers <x86@kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>
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Message-Id: <FD3482AC-3FB0-41DE-9347-5BD7C3DE8B11@amacapital.net>
References: <20190612170834.14855-1-mhillenb@amazon.de> <eecc856f-7f3f-ed11-3457-ea832351e963@intel.com> <A542C98B-486C-4849-9DAC-2355F0F89A20@amacapital.net> <3cd533c1-3f18-a84f-fbb2-264751ed3eeb@intel.com>
To:     Dave Hansen <dave.hansen@intel.com>
Sender: linux-kernel-owner@vger.kernel.org
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> On Jun 12, 2019, at 1:41 PM, Dave Hansen <dave.hansen@intel.com> wrote:
>=20
> On 6/12/19 1:27 PM, Andy Lutomirski wrote:
>>> We've discussed having per-cpu page tables where a given PGD is
>>> only in use from one CPU at a time.  I *think* this scheme still
>>> works in such a case, it just adds one more PGD entry that would
>>> have to context-switched.
>> Fair warning: Linus is on record as absolutely hating this idea. He
>> might change his mind, but it=E2=80=99s an uphill battle.
>=20
> Just to be clear, are you referring to the per-cpu PGDs, or to this
> patch set with a per-mm kernel area?

per-CPU PGDs=