From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752739AbdJ3I5S (ORCPT ); Mon, 30 Oct 2017 04:57:18 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:39048 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752458AbdJ3I5Q (ORCPT ); Mon, 30 Oct 2017 04:57:16 -0400 Subject: Re: [RFC 00/19] KVM: s390/crypto/vfio: guest dedicated crypto adapters To: Cornelia Huck , Tony Krowiak Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com, alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com, qemu-s390x@nongnu.org, jjherne@linux.vnet.ibm.com, thuth@redhat.com, pasic@linux.vnet.ibm.com, qemu-devel , Erik Skultety , "Daniel P. Berrange" References: <1507916344-3896-1-git-send-email-akrowiak@linux.vnet.ibm.com> <20171029121122.122412ca.cohuck@redhat.com> From: Christian Borntraeger Date: Mon, 30 Oct 2017 09:57:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20171029121122.122412ca.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 17103008-0040-0000-0000-0000040858F4 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17103008-0041-0000-0000-000020AAD708 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-10-30_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1710300127 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org adding qemu devel and add Daniel and Erik from libvirt to keep them in the loop. On 10/29/2017 12:11 PM, Cornelia Huck wrote: > On Fri, 13 Oct 2017 13:38:45 -0400 > Tony Krowiak wrote: > >> Tony Krowiak (19): >> KVM: s390: SIE considerations for AP Queue virtualization >> KVM: s390: refactor crypto initialization >> s390/zcrypt: new AP matrix bus >> s390/zcrypt: create an AP matrix device on the AP matrix bus >> s390/zcrypt: base implementation of AP matrix device driver >> s390/zcrypt: register matrix device with VFIO mediated device >> framework >> KVM: s390: introduce AP matrix configuration interface >> s390/zcrypt: support for assigning adapters to matrix mdev >> s390/zcrypt: validate adapter assignment >> s390/zcrypt: sysfs interfaces supporting AP domain assignment >> s390/zcrypt: validate domain assignment >> s390/zcrypt: sysfs support for control domain assignment >> s390/zcrypt: validate control domain assignment >> KVM: s390: Connect the AP mediated matrix device to KVM >> s390/zcrypt: introduce ioctl access to VFIO AP Matrix driver >> KVM: s390: interface to configure KVM guest's AP matrix >> KVM: s390: validate input to AP matrix config interface >> KVM: s390: New ioctl to configure KVM guest's AP matrix >> s390/facilities: enable AP facilities needed by guest > > I'll try to summarize all of this in my own words, both to make sure I > understand the design correctly and to give others a different view on > this. > > [I'm completely disregarding control domains here.] > > On s390, we have cryptographic coprocessor cards, which are modeled on > Linux as devices on the AP bus. There's also a concept called domains, > which means an individual queue of a crypto device is basically a > (card,domain) tuple. We model this something like the following > (assuming we have access to cards 3 and 4 and domains 1 and 2): > > AP -> card3 -> queue (3,1) > -> queue (3,2) > -> card4 -> queue (4,1) > -> queue (4,2) > > (The AP bus is a bit different for backwards compat.) > > If we want to virtualize this, we can use a feature provided by the > hardware. We basically attach a satellite control block to our main > hardware virtualization control block and the hardware takes care of > (mostly) everything. > > For this control block, we don't specify explicit tuples, but a list of > cards and a list of domains. The guest will get access to the cross > product. > > Because of this, we need to take care that the lists provided to > different guests don't overlap; i.e., we need to enforce sane > configurations. Otherwise, one guest may get access to things like > secret keys for another guest. > > The idea of this patch set is to introduce a new device, the matrix > device. This matrix device hangs off a different root and acts as the > node where mdev devices hang off. > > If you now want to give the tuples (4,1) and (4,2), you need to do the > following: > > - Unbind the (4,1) and (4,2) tuples from their ap bus driver. > - Bind the (4,1) and (4,2) tuples to the ap matrix driver. > - Create the mediated device. > - Assign card 4 and domains 1 and 2. > > QEMU will now simply consume the mediated device and things should work. > This is probably the shortest possible summary I can imagine. Tony can you double check if it matches your understanding as well?