From patchwork Wed Mar 11 13:21:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Janosch Frank X-Patchwork-Id: 11431775 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 17259924 for ; Wed, 11 Mar 2020 13:31:48 +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 EBE9A20873 for ; Wed, 11 Mar 2020 13:31:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EBE9A20873 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:51960 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jC1Sd-0003Kt-59 for patchwork-qemu-devel@patchwork.kernel.org; Wed, 11 Mar 2020 09:31:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58424) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jC1Lq-0008Ey-2S for qemu-devel@nongnu.org; Wed, 11 Mar 2020 09:24:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jC1Lo-0007IL-Mx for qemu-devel@nongnu.org; Wed, 11 Mar 2020 09:24:45 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:61052) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jC1Lo-0007I5-E2 for qemu-devel@nongnu.org; Wed, 11 Mar 2020 09:24:44 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 02BDLsdv194032 for ; Wed, 11 Mar 2020 09:24:43 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2yq0hbh950-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 11 Mar 2020 09:24:40 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 11 Mar 2020 13:22:30 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 02BDMUkI62914682 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 11 Mar 2020 13:22:30 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DE86052063; Wed, 11 Mar 2020 13:22:29 +0000 (GMT) Received: from localhost.localdomain (unknown [9.145.36.208]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id BDB165205A; Wed, 11 Mar 2020 13:22:28 +0000 (GMT) From: Janosch Frank To: qemu-devel@nongnu.org Subject: [PATCH v9 14/15] docs: Add protvirt docs Date: Wed, 11 Mar 2020 09:21:50 -0400 X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200311132151.172389-1-frankja@linux.ibm.com> References: <20200311132151.172389-1-frankja@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 20031113-0028-0000-0000-000003E31FE3 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20031113-0029-0000-0000-000024A86451 Message-Id: <20200311132151.172389-15-frankja@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.572 definitions=2020-03-11_05:2020-03-11, 2020-03-11 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 malwarescore=0 impostorscore=0 phishscore=0 lowpriorityscore=0 adultscore=0 bulkscore=0 priorityscore=1501 clxscore=1015 suspectscore=1 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2003110085 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] X-Received-From: 148.163.156.1 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: borntraeger@de.ibm.com, qemu-s390x@nongnu.org, cohuck@redhat.com, david@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" Lets add some documentation for the Protected VM functionality. Signed-off-by: Janosch Frank Acked-by: David Hildenbrand Reviewed-by: Claudio Imbrenda --- docs/system/index.rst | 1 + docs/system/protvirt.rst | 56 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) create mode 100644 docs/system/protvirt.rst diff --git a/docs/system/index.rst b/docs/system/index.rst index 6e5f20fa1333ce23..74afbd7cc3fc0296 100644 --- a/docs/system/index.rst +++ b/docs/system/index.rst @@ -34,3 +34,4 @@ Contents: deprecated build-platforms license + protvirt diff --git a/docs/system/protvirt.rst b/docs/system/protvirt.rst new file mode 100644 index 0000000000000000..6c8cf0f7910eae86 --- /dev/null +++ b/docs/system/protvirt.rst @@ -0,0 +1,56 @@ +Protected Virtualization on s390x +================================= + +The memory and most of the registers of Protected Virtual Machines +(PVMs) are encrypted or inaccessible to the hypervisor, effectively +prohibiting VM introspection when the VM is running. At rest, PVMs are +encrypted and can only be decrypted by the firmware, represented by an +entity called Ultravisor, of specific IBM Z machines. + + +Prerequisites +------------- + +To run PVMs a machine with the Protected Virtualization feature +which is indicated by the Ultravisor Call facility (stfle bit +158) is required. The Ultravisor needs to be initialized at boot by +setting `prot_virt=1` on the kernel command line. + +If those requirements are met, the capability `KVM_CAP_S390_PROTECTED` +will indicate that KVM can support PVMs on that LPAR. + + +QEMU Settings +------------- + +To indicate to the VM that it can transition into protected mode, the +`Unpack facility` (stfle bit 161 represented by the feature +`S390_FEAT_UNPACK`) needs to be part of the cpu model of the VM. + +All I/O devices need to use the IOMMU. +Passthrough (vfio) devices are currently not supported. + +Host huge page backings are not supported. However guests can use huge +pages as indicated by its facilities. + + +Boot Process +------------ + +A secure guest image can either be loaded from disk or supplied on the +QEMU command line. Booting from disk is done by the unmodified +s390-ccw BIOS. I.e., the bootmap is interpreted, multiple components +are read into memory and control is transferred to one of the +components (zipl stage3). Stag3 does some fixups and then transfers +control to some program residing in guest memory, which is normally +the OS kernel. The secure image has another component prepended +(stage3a) that uses the new diag308 subcodes 8 and 10 to trigger the +transition into secure mode. + +Booting from the image supplied via the QEMU command line requires +that the file passed via -kernel has the same memory layout as would +result from the disk boot. This memory layout includes the encrypted +components (kernel, initrd, cmdline), the stage3a loader and +metadata. In case this boot method is used, the command line +options -initrd and -cmdline are ineffective. The preparation of a PVM +image is done by genprotimg of the s390-tools package.