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04 Jul 2020 01:33:09 +0000 Received: from EX13MTAUWA001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan2.iad.amazon.com [10.40.159.162]) by email-inbound-relay-1d-37fd6b3d.us-east-1.amazon.com (Postfix) with ESMTPS id BDF432850D9; Sat, 4 Jul 2020 01:33:07 +0000 (UTC) Received: from EX13D01UWA003.ant.amazon.com (10.43.160.107) by EX13MTAUWA001.ant.amazon.com (10.43.160.118) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sat, 4 Jul 2020 01:33:07 +0000 Received: from [192.168.1.11] (10.43.160.48) by EX13d01UWA003.ant.amazon.com (10.43.160.107) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sat, 4 Jul 2020 01:33:06 +0000 From: Colm =?utf-8?q?MacC=C3=A1rthaigh?= To: Jann Horn CC: "Catangiu, Adrian Costin" , , , , , , , , , , , , , , , , "Graf (AWS), Alexander" , "Singh, Balbir" , "Sandu, Andrei" , "Brooker, Marc" , "Weiss, Radu" , "Manwaring, Derek" Subject: Re: [RFC]: mm,power: introduce MADV_WIPEONSUSPEND Date: Fri, 3 Jul 2020 18:33:05 -0700 X-Mailer: MailMate Trial (1.13.1r5671) Message-ID: <5E780027-A6A7-4ED3-AA76-16C2036FF8D4@amazon.com> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed X-Originating-IP: [10.43.160.48] X-ClientProxiedBy: EX13D36UWB003.ant.amazon.com (10.43.161.118) To EX13d01UWA003.ant.amazon.com (10.43.160.107) X-Rspamd-Queue-Id: 8A211180442C0 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 3 Jul 2020, at 4:04, Jann Horn wrote: >> - Provides a simple mechanism to avoid RAM exfiltration during >> traditional sleep/hibernate on a laptop or desktop when memory, >> and thus secrets, are vulnerable to offline tampering or=20 >> inspection. > > For the first usecase, I wonder which way around this would work > better - do the wiping when a VM is saved, or do it when the VM is > restored? I guess that at least in some scenarios, doing it on restore > would be nicer because that way the hypervisor can always instantly > save a VM without having to wait for the guest to say "alright, I'm > ready" - especially if someone e.g. wants to take a snapshot of a > running VM while keeping it running? Or do hypervisors inject such > ACPI transitions every time they snapshot/save/restore a VM anyway? Just to answer this - I=E2=80=99d expect wipe-after-save rather than=20 wipe-on-restore to be common for some. That provides the most defense=20 against secrets ending up on disk or some other durable medium when the=20 VM images are being saved. - Colm