From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751839AbdJ2LLf (ORCPT ); Sun, 29 Oct 2017 07:11:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33452 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751221AbdJ2LLd (ORCPT ); Sun, 29 Oct 2017 07:11:33 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 9B64980090 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=cohuck@redhat.com Date: Sun, 29 Oct 2017 12:11:22 +0100 From: Cornelia Huck To: 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, borntraeger@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 Subject: Re: [RFC 00/19] KVM: s390/crypto/vfio: guest dedicated crypto adapters Message-ID: <20171029121122.122412ca.cohuck@redhat.com> In-Reply-To: <1507916344-3896-1-git-send-email-akrowiak@linux.vnet.ibm.com> References: <1507916344-3896-1-git-send-email-akrowiak@linux.vnet.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Sun, 29 Oct 2017 11:11:33 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.