From nobody Mon Feb 9 11:33:37 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1624046498760613.7599166163751; Fri, 18 Jun 2021 13:01:38 -0700 (PDT) Received: from localhost ([::1]:50462 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1luKgL-00065g-BE for importer@patchew.org; Fri, 18 Jun 2021 16:01:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33840) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1luKXs-0008HU-9h for qemu-devel@nongnu.org; Fri, 18 Jun 2021 15:52:52 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:55129) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1luKXp-0006ri-Mt for qemu-devel@nongnu.org; Fri, 18 Jun 2021 15:52:52 -0400 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-324-JYmmaoDONtaqz7jPTYfu_w-1; Fri, 18 Jun 2021 15:52:45 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E63FF804140; Fri, 18 Jun 2021 19:52:44 +0000 (UTC) Received: from localhost (unknown [10.22.9.9]) by smtp.corp.redhat.com (Postfix) with ESMTP id 01F712C00F; Fri, 18 Jun 2021 19:52:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624045968; 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=UgnhNLRla1fbf6uIxEwSl+pw9ZKjw537w0nBer4HyNk=; b=MTWTAFCqby/4G5+LN14qFLaRAZBSD6sgfmkvqUSBDhLIW6Qes7PjNLRCmPSoBFyaQixJGi /iESFGzgo9Dd9WJGmcQUDc2vfdRf/mvmposo18nMaYr1mt9F5KvbhpQwIhNKvTUwv87qm0 XPd/aT1y18LMkGSiysN1XEvo6AJ9w78= X-MC-Unique: JYmmaoDONtaqz7jPTYfu_w-1 From: Eduardo Habkost To: Peter Maydell , qemu-devel@nongnu.org Subject: [PULL 4/7] docs: Add SEV-ES documentation to amd-memory-encryption.txt Date: Fri, 18 Jun 2021 15:52:34 -0400 Message-Id: <20210618195237.442548-5-ehabkost@redhat.com> In-Reply-To: <20210618195237.442548-1-ehabkost@redhat.com> References: <20210618195237.442548-1-ehabkost@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ehabkost@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=ehabkost@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=-0.194, 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: Tom Lendacky , Eduardo Habkost , Connor Kuehl , Richard Henderson , Paolo Bonzini , Laszlo Ersek Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" 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 Acked-by: Laszlo Ersek Reviewed-by: Connor Kuehl Message-Id: Signed-off-by: Eduardo Habkost --- 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 ed85159ea7d..ffca382b5f5 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. =20 +Secure Encrypted Virtualization - Encrypted State (SEV-ES) builds on the S= EV +support to additionally protect the guest register state. In order to allo= w a +hypervisor to perform functions on behalf of a guest, there is architectur= al +support for notifying a guest's operating system when certain types of VME= XITs +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 V= M, encrypt the boot images and provide a measurement than can be used as an attestation of a successful launch. =20 +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 with= in the firmware. To create this context, guest owner must provide a guest pol= icy, its public Diffie-Hellman key (PDH) and session parameters. These inputs @@ -40,6 +50,12 @@ The guest policy can be provided via the 'policy' proper= ty (see below) # ${QEMU} \ sev-guest,id=3Dsev0,policy=3D0x1...\ =20 +Setting the "SEV-ES required" policy bit (bit 2) will launch the guest as a +SEV-ES guest (see below) + +# ${QEMU} \ + sev-guest,id=3Dsev0,policy=3D0x5...\ + The guest owner provided DH certificate and session parameters will be use= d to establish a cryptographic session with the guest owner to negotiate keys u= sed 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 calcu= lates the measurement of the memory contents as it encrypts. =20 -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 t= he -firmware. The guest owner may wait to provide the guest confidential infor= mation -until it can verify the attestation measurement. Since the guest owner kno= ws 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 al= so +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 se= nt +to the guest owner as an attestation that the memory and VMSAs were encryp= ted +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. =20 LAUNCH_FINISH finalizes the guest launch and destroys the cryptographic context. @@ -75,6 +97,22 @@ To launch a SEV guest -machine ...,confidential-guest-support=3Dsev0 \ -object sev-guest,id=3Dsev0,cbitpos=3D47,reduced-phys-bits=3D1 =20 +To launch a SEV-ES guest + +# ${QEMU} \ + -machine ...,confidential-guest-support=3Dsev0 \ + -object sev-guest,id=3Dsev0,cbitpos=3D47,reduced-phys-bits=3D1,policy= =3D0x5 + +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/hypervi= sor, +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 re= gister + 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: =20 KVM Forum slides: http://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualiz= atoin_Memory_Encryption_Technology.pdf +https://www.linux-kvm.org/images/9/94/Extending-Secure-Encrypted-Virtualiz= ation-with-SEV-ES-Thomas-Lendacky-AMD.pdf =20 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 --=20 2.31.1