From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5DBB3C433E0 for ; Thu, 25 Jun 2020 05:49:49 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 29FD82063A for ; Thu, 25 Jun 2020 05:49:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.b="f4RMuflO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 29FD82063A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:57506 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1joKlg-00040X-DX for qemu-devel@archiver.kernel.org; Thu, 25 Jun 2020 01:49:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33436) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1joKjg-0000lS-06; Thu, 25 Jun 2020 01:47:44 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:50083 helo=ozlabs.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1joKjd-0004VD-SS; Thu, 25 Jun 2020 01:47:43 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 49spv509mmz9sT9; Thu, 25 Jun 2020 15:47:28 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1593064049; bh=gnSHCl8vwImx7o9H0Ein+TSImN511M/Zl2woK1V+Fks=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=f4RMuflOGe+siIzPupiMAEhRQvHrh8t+/mvPGK44eZgNtCNrBq8v89NlHTANwcj3B otoGXUAYuJua6V1vH89LZRpp2hW3l4alcIJp4MgF4/x1Q2GeUTadOXLyZWzitFucsF C4BFxkAUXDW7athopwzP1jkL17XoNMP3oDaryPn0= Date: Thu, 25 Jun 2020 15:44:48 +1000 From: David Gibson To: Christian Borntraeger Subject: Re: [PATCH v3 0/9] Generalize memory encryption models Message-ID: <20200625054448.GF172395@umbus.fritz.box> References: <20200619020602.118306-1-david@gibson.dropbear.id.au> <2fa7c84a-6929-ef04-1d61-f76a4cac35f5@de.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="FeAIMMcddNRN4P4/" Content-Disposition: inline In-Reply-To: <2fa7c84a-6929-ef04-1d61-f76a4cac35f5@de.ibm.com> Received-SPF: pass client-ip=203.11.71.1; envelope-from=dgibson@ozlabs.org; helo=ozlabs.org X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/24 22:09:21 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -9 X-Spam_score: -1.0 X-Spam_bar: - X-Spam_report: (-1.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=1, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pair@us.ibm.com, brijesh.singh@amd.com, frankja@linux.ibm.com, kvm@vger.kernel.org, mst@redhat.com, cohuck@redhat.com, david@redhat.com, qemu-devel@nongnu.org, dgilbert@redhat.com, pasic@linux.ibm.com, qemu-s390x@nongnu.org, qemu-ppc@nongnu.org, pbonzini@redhat.com, Richard Henderson , mdroth@linux.vnet.ibm.com, Eduardo Habkost Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --FeAIMMcddNRN4P4/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jun 22, 2020 at 04:27:28PM +0200, Christian Borntraeger wrote: > On 19.06.20 04:05, David Gibson wrote: > > A number of hardware platforms are implementing mechanisms whereby the > > hypervisor does not have unfettered access to guest memory, in order > > to mitigate the security impact of a compromised hypervisor. > >=20 > > AMD's SEV implements this with in-cpu memory encryption, and Intel has > > its own memory encryption mechanism. POWER has an upcoming mechanism > > to accomplish this in a different way, using a new memory protection > > level plus a small trusted ultravisor. s390 also has a protected > > execution environment. > >=20 > > The current code (committed or draft) for these features has each > > platform's version configured entirely differently. That doesn't seem > > ideal for users, or particularly for management layers. > >=20 > > AMD SEV introduces a notionally generic machine option > > "machine-encryption", but it doesn't actually cover any cases other > > than SEV. > >=20 > > This series is a proposal to at least partially unify configuration > > for these mechanisms, by renaming and generalizing AMD's > > "memory-encryption" property. It is replaced by a > > "host-trust-limitation" property pointing to a platform specific > > object which configures and manages the specific details. > >=20 > > For now this series covers just AMD SEV and POWER PEF. I'm hoping it > > can be extended to cover the Intel and s390 mechanisms as well, > > though. >=20 > Let me try to summarize what I understand what you try to achieve: > one command line parameter for all platforms that=20 >=20 > common across all platforms: > - disable KSM > - by default enables iommu_platform Pretty much, yes. Plus, in future if we discover other things that don't make sense in the context of a guest whose memory we can't freely access, it can check for those and set sane defaults accordingly. > per platform: > - setup the necessary encryption scheme when appropriate > - block migration That's true for now, but I believe there are plans to make secure guests migratable, so that's not an inherent property. > -.... >=20 >=20 > The tricky part is certainly the per platform thing. For example on > s390 we just have a cpumodel flag that provides interfaces to the guest > to switch into protected mode via the ultravisor. This works perfectly > fine with the host model, so no need to configure anything. The platform > code then disables KSM _on_switchover_ and not in general. Right, because your platform code is aware of the switchover. On POWER, we aren't. > Because the=20 > guest CAN switch into protected, but it does not have to. >=20 > So this feels really hard to do right. Would a virtual BoF on KVM forum > be too late? We had a BoF on protected guests last year and that was > valuable. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --FeAIMMcddNRN4P4/ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEdfRlhq5hpmzETofcbDjKyiDZs5IFAl70OdAACgkQbDjKyiDZ s5IUJQ/9EKOS1WmdsXTeIqzvdTE1f0NTDsgME+rPrh8z6e3ZcJgY1Fei6Clr2Amq +F5xcLnOAq8P8zfk6dpjyZ8oa0lyxfC6j9n9raoQMJrDL7e4mricPn7ERaSrBcyI 5rTOkx1i64cdlRR1/ajN2N8KpR+IkiTkJVxlXIO8xq7Vgha/sP3hb2qyMLFeCd1H wj59bduUNo1BMMrU6EAC13S+ZpuiCd10V6XMfmaXGN4Y6IWAKckLCIjTtjWuxA1A 7GNNt88iIFKkIHd7mYLwuHBeryO2D/D/VVym1ssYUfzDWqG6J6K5lwpcjkbrbCLL rA6N0kIbHZqcIaHgfqf3j3V16oh9r3KJydjDHR2h75lPcqqZNNZ3f5xMFSnYWrXv 6CJ2cxfcI3eF1zPFwVSTOmd8xOx2YJPlVU1RNurwBxO4OVoljsdqfWSErkfB30Zd 7oHOQ9tePXBv3rkzgGpF9RUnqFz2SNyGfzQjvQAzlXTNQRwp6KVS1NazEa6e+VI4 t42scr5er3V9qyp0mwoyq86RAbcObNZS8JOya9RqYJTrJdGFHVeWbSBKYX9vUm0H cPtlwYHMGT9A+Qk7tbPK4m7kLtu4EMwU6jJl53Dlm5/7AB/Dla+O2/EXQ5cP5vbm NEhNz5N0yx/v/douwEJCJ8Catj81QtVn+mMh4KfUGt1EFwnufW0= =6tvg -----END PGP SIGNATURE----- --FeAIMMcddNRN4P4/--