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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 B52CCC43460 for ; Mon, 26 Apr 2021 12:34:32 +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 065CB61178 for ; Mon, 26 Apr 2021 12:34:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 065CB61178 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49374 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lb0Rb-0006qn-05 for qemu-devel@archiver.kernel.org; Mon, 26 Apr 2021 08:34:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49500) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lb0QU-00064n-Uu for qemu-devel@nongnu.org; Mon, 26 Apr 2021 08:33:24 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49355) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lb0QR-00083a-6t for qemu-devel@nongnu.org; Mon, 26 Apr 2021 08:33:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619440398; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bcO9IJ2wJjilahx3XVUBlAnlFuhXbdsPjHAMqniYCe0=; b=YbRdXTUi+3E5F2h4V38xkj2ILE5m91esi9R6BoBghNLkVz0ptVuZHDVZUhSk2GaIruZJlV EHHyQd/HduO5rSz2p9PM5zkvI2W9yqDds8BhVRwhyCznd8l0gLi0Gm6ArOT2peTsDGOUwJ sw82xRVAxQLvm0xrKOSh8b0kRyolKAk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-190-DGaz6j_aO8O4GeNHzIXuOw-1; Mon, 26 Apr 2021 08:33:15 -0400 X-MC-Unique: DGaz6j_aO8O4GeNHzIXuOw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1D2A7100671D; Mon, 26 Apr 2021 12:33:14 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-115-153.ams2.redhat.com [10.36.115.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id A49E219C78; Mon, 26 Apr 2021 12:33:11 +0000 (UTC) Subject: Re: [PATCH v2 2/3] docs: Add SEV-ES documentation to amd-memory-encryption.txt To: Tom Lendacky , qemu-devel@nongnu.org References: From: Laszlo Ersek Message-ID: Date: Mon, 26 Apr 2021 14:33:10 +0200 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lersek@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=lersek@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.219, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: Pavel Hrdina , "Daniel P . Berrange" , Eduardo Habkost , Michal Privoznik , "Dr. David Alan Gilbert" , Brijesh Singh , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 04/23/21 22:08, Tom Lendacky wrote: > From: Tom Lendacky > > Update the amd-memory-encryption.txt file with information about SEV-ES, > including how to launch an SEV-ES guest and some of the differences > between SEV and SEV-ES guests in regards to launching and measuring the > guest. > > Signed-off-by: Tom Lendacky > --- > docs/amd-memory-encryption.txt | 54 +++++++++++++++++++++++++++++----- > 1 file changed, 47 insertions(+), 7 deletions(-) > > diff --git a/docs/amd-memory-encryption.txt b/docs/amd-memory-encryption.txt > index ed85159ea7..ffca382b5f 100644 > --- a/docs/amd-memory-encryption.txt > +++ b/docs/amd-memory-encryption.txt > @@ -15,6 +15,13 @@ includes commands for launching, snapshotting, migrating and debugging the > encrypted guest. These SEV commands can be issued via KVM_MEMORY_ENCRYPT_OP > ioctls. > > +Secure Encrypted Virtualization - Encrypted State (SEV-ES) builds on the SEV > +support to additionally protect the guest register state. In order to allow a > +hypervisor to perform functions on behalf of a guest, there is architectural > +support for notifying a guest's operating system when certain types of VMEXITs > +are about to occur. This allows the guest to selectively share information with > +the hypervisor to satisfy the requested function. > + > Launching > --------- > Boot images (such as bios) must be encrypted before a guest can be booted. The > @@ -24,6 +31,9 @@ together generate a fresh memory encryption key for the VM, encrypt the boot > images and provide a measurement than can be used as an attestation of a > successful launch. > > +For a SEV-ES guest, the LAUNCH_UPDATE_VMSA command is also used to encrypt the > +guest register state, or VM save area (VMSA), for all of the guest vCPUs. > + > LAUNCH_START is called first to create a cryptographic launch context within > the firmware. To create this context, guest owner must provide a guest policy, > its public Diffie-Hellman key (PDH) and session parameters. These inputs > @@ -40,6 +50,12 @@ The guest policy can be provided via the 'policy' property (see below) > # ${QEMU} \ > sev-guest,id=sev0,policy=0x1...\ > > +Setting the "SEV-ES required" policy bit (bit 2) will launch the guest as a > +SEV-ES guest (see below) > + > +# ${QEMU} \ > + sev-guest,id=sev0,policy=0x5...\ > + > The guest owner provided DH certificate and session parameters will be used to > establish a cryptographic session with the guest owner to negotiate keys used > for the attestation. > @@ -55,13 +71,19 @@ created via the LAUNCH_START command. If required, this command can be called > multiple times to encrypt different memory regions. The command also calculates > the measurement of the memory contents as it encrypts. > > -LAUNCH_MEASURE can be used to retrieve the measurement of encrypted memory. > -This measurement is a signature of the memory contents that can be sent to the > -guest owner as an attestation that the memory was encrypted correctly by the > -firmware. The guest owner may wait to provide the guest confidential information > -until it can verify the attestation measurement. Since the guest owner knows the > -initial contents of the guest at boot, the attestation measurement can be > -verified by comparing it to what the guest owner expects. > +LAUNCH_UPDATE_VMSA encrypts all the vCPU VMSAs for a SEV-ES guest using the > +cryptographic context created via the LAUNCH_START command. The command also > +calculates the measurement of the VMSAs as it encrypts them. > + > +LAUNCH_MEASURE can be used to retrieve the measurement of encrypted memory and, > +for a SEV-ES guest, encrypted VMSAs. This measurement is a signature of the > +memory contents and, for a SEV-ES guest, the VMSA contents, that can be sent > +to the guest owner as an attestation that the memory and VMSAs were encrypted > +correctly by the firmware. The guest owner may wait to provide the guest > +confidential information until it can verify the attestation measurement. > +Since the guest owner knows the initial contents of the guest at boot, the > +attestation measurement can be verified by comparing it to what the guest owner > +expects. > > LAUNCH_FINISH finalizes the guest launch and destroys the cryptographic > context. > @@ -75,6 +97,22 @@ To launch a SEV guest > -machine ...,confidential-guest-support=sev0 \ > -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 > > +To launch a SEV-ES guest > + > +# ${QEMU} \ > + -machine ...,confidential-guest-support=sev0 \ > + -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1,policy=0x5 > + > +An SEV-ES guest has some restrictions as compared to a SEV guest. Because the > +guest register state is encrypted and cannot be updated by the VMM/hypervisor, > +a SEV-ES guest: > + - Does not support SMM - SMM support requires updating the guest register > + state. > + - Does not support reboot - a system reset requires updating the guest register > + state. > + - Requires in-kernel irqchip - the burden is placed on the hypervisor to > + manage booting APs. > + > Debugging > ----------- > Since the memory contents of a SEV guest are encrypted, hypervisor access to > @@ -101,8 +139,10 @@ Secure Encrypted Virtualization Key Management: > > KVM Forum slides: > http://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualizatoin_Memory_Encryption_Technology.pdf > +https://www.linux-kvm.org/images/9/94/Extending-Secure-Encrypted-Virtualization-with-SEV-ES-Thomas-Lendacky-AMD.pdf > > AMD64 Architecture Programmer's Manual: > http://support.amd.com/TechDocs/24593.pdf > SME is section 7.10 > SEV is section 15.34 > + SEV-ES is section 15.35 > Looks good to me. Acked-by: Laszlo Ersek