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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 7EC7EC10F11 for ; Wed, 10 Apr 2019 08:26:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52948206B6 for ; Wed, 10 Apr 2019 08:26:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729578AbfDJI0E (ORCPT ); Wed, 10 Apr 2019 04:26:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55570 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729258AbfDJI0E (ORCPT ); Wed, 10 Apr 2019 04:26:04 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1F082308626F; Wed, 10 Apr 2019 08:26:04 +0000 (UTC) Received: from gondolin (ovpn-204-33.brq.redhat.com [10.40.204.33]) by smtp.corp.redhat.com (Postfix) with ESMTP id EA4955C28F; Wed, 10 Apr 2019 08:26:00 +0000 (UTC) Date: Wed, 10 Apr 2019 10:25:57 +0200 From: Cornelia Huck To: Halil Pasic Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, Martin Schwidefsky , Sebastian Ott , virtualization@lists.linux-foundation.org, Christian Borntraeger , Viktor Mihajlovski , Vasily Gorbik , Janosch Frank , Claudio Imbrenda , Farhan Ali , Eric Farman Subject: Re: [RFC PATCH 05/12] s390/cio: add protected virtualization support to cio Message-ID: <20190410102557.1ba89d96.cohuck@redhat.com> In-Reply-To: <20190410021044.4da3e847@oc2783563651> References: <20190404231622.52531-1-pasic@linux.ibm.com> <20190404231622.52531-6-pasic@linux.ibm.com> <20190409195548.6dea6e40.cohuck@redhat.com> <20190410021044.4da3e847@oc2783563651> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Wed, 10 Apr 2019 08:26:04 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, 10 Apr 2019 02:10:44 +0200 Halil Pasic wrote: > On Tue, 9 Apr 2019 19:55:48 +0200 > Cornelia Huck wrote: > > > On Fri, 5 Apr 2019 01:16:15 +0200 > > Halil Pasic wrote: > > > Thus we need to make sure any memory that is used for communication with > > > the hypervisor is shared. > > > > In this context, does 'hypervisor' always mean 'QEMU/KVM'? If Other > > Hypervisors implement protected virtualization, we probably need to > > make sure that all common I/O layer control blocks are in the dma area > > (including e.g. QDIO), not just what virtio-ccw devices use. > > > > Hypervisor could theoretically be something different than QEMU/KVM. Yet, > as stated before, this series is about getting virtio-ccw working > (modulo the TODOs). Sure, just wanted to point it out. If this is "enable the common I/O layer, except for QDIO" or so, that would sound fine to me :) > > [..] > > > > > > > > So, this leaves some things I'm not sure about, especially as I do not > > know the architecture of this new feature. > > > > - This applies only to asynchronously handled things, it seems? So > > things like control blocks modified by stsch/msch/etc does not need > > special treatment? > > I had a feeble attempt at explaining this in the cover letter: > > * make sure that virtio-ccw specific stuff uses shared memory when > talking to the hypervisor (except communication blocks like ORB, these > are handled by the hypervisor) > > Unfortunately the last 'hypervisor' was supposed to be 'ultravisor'. > > I.e. the ultravisor will take care of exposing the control blocks > to the hypervisor (and of changes as well). Yeah, that "control blocks" or "communication blocks" leaves me a bit fuzzy :) So, what is a high-level summary of areas that need the treatment? What I get from looking at the patches so far, it's: - stuff that is written by the hypervisor's interrupt injection code: IRB, indicators, etc. - buffers that are filled by a channel program: sense, sense id, etc. - ccws themselves (because of translation?)