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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 89159C54EAA for ; Fri, 27 Jan 2023 10:31:12 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pLM03-0008M5-PU; Fri, 27 Jan 2023 05:30:27 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pLM01-0008Ln-7v for qemu-devel@nongnu.org; Fri, 27 Jan 2023 05:30:25 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pLLzz-0007h9-5y for qemu-devel@nongnu.org; Fri, 27 Jan 2023 05:30:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674815421; 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: in-reply-to:in-reply-to:references:references; bh=qAJjxH4056mS2hC4Dl+naq125voeuwyxSHx/fFJ1a1U=; b=VooJG1gTTMcRDedb+M6TFLvHrMNeQbFxls7790atWqnKZA2Xk3ig/VrlKlvlH3ilsy46Ti r7grjTqQlRNxWC+XXGwOmHULEb6PsftYTM3Y2jSEtMqbecnq2IEW3J7qhBOrpKloIELdBL +T2LvDhdq3G8HJx+Bnxru2GdUcUlxXE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-125-yAe9yX9xPLS11QAihDp9Og-1; Fri, 27 Jan 2023 05:30:18 -0500 X-MC-Unique: yAe9yX9xPLS11QAihDp9Og-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id AA413280BCBB; Fri, 27 Jan 2023 10:30:16 +0000 (UTC) Received: from localhost (unknown [10.39.193.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 104C114171C0; Fri, 27 Jan 2023 10:30:15 +0000 (UTC) From: Cornelia Huck To: Sebastian Mitterle , qemu-devel@nongnu.org Cc: thuth@redhat.com, clegoate@redhat.com, qemu-trivial@nongnu.org, qemu-s390x@nongnu.org Subject: Re: [PATCH v2] docs/s390x/pcidevices: document pci devices on s390x In-Reply-To: <20230127084604.53175-1-smitterl@redhat.com> Organization: Red Hat GmbH References: <20230127084604.53175-1-smitterl@redhat.com> User-Agent: Notmuch/0.37 (https://notmuchmail.org) Date: Fri, 27 Jan 2023 11:30:13 +0100 Message-ID: <87h6wcuv62.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Jan 27 2023, Sebastian Mitterle wrote: > Add some documentation about the zpci device and how > to use it with pci devices on s390x. > > Used source: Cornelia Huck's blog post > https://people.redhat.com/~cohuck/2018/02/19/notes-on-pci-on-s390x.html > > Signed-off-by: Sebastian Mitterle > --- > v2: move section below 'Device support' > --- > docs/system/s390x/pcidevices.rst | 34 ++++++++++++++++++++++++++++++++ > docs/system/target-s390x.rst | 1 + > 2 files changed, 35 insertions(+) > create mode 100644 docs/system/s390x/pcidevices.rst > > diff --git a/docs/system/s390x/pcidevices.rst b/docs/system/s390x/pcidevices.rst > new file mode 100644 > index 0000000000..fec905d6e6 > --- /dev/null > +++ b/docs/system/s390x/pcidevices.rst > @@ -0,0 +1,34 @@ > +PCI devices on s390x > +==================== > + > +PCI devices on s390x work differently than on other architectures. add "and need to be configured in a slightly different way." ? > + > +To start with, using a PCI device requires the additional ``zpci`` device. For example, I think the "zpci" device is not technically "required" (ISTR that we autogenerate it, if needed); however, you need it if you actually want to specify uid/fid/... what about: "Every PCI device is linked with an additional ``zpci`` device. While the ``zpci`` device will be autogenerated if not specified, it is recommended to specify it explicitly so that you can pass s390-specific PCI configuration." ? > +in order to pass a PCI device ``0000:00:00.0`` through you'd specify:: > + > + qemu-system-s390x ... \ > + -device zpci,uid=1,fid=0,target=hostdev0,id=zpci1 \ > + -device vfio-pci,host=0000:00:00.0,id=hostdev0 > + > +Here, the zpci device is joined with the PCI device via the ``target`` property. > + > +Note that we don't set bus, slot or function here for the guest as is common in other > +PCI implementations. Topology information is not available on s390x. Instead, ``uid`` "Topology information is not available on s390x, and the guest will not see any of the bus/slot/function information specified on the command line." ? > +and ``fid`` determine how the device is presented to the guest operating system. > + > +In case of Linux, ``uid`` will be used in the ``domain`` part of the PCI identifier, and > +``fid`` identifies the physical slot, i.e.:: > + > + qemu-system-s390x ... \ > + -device zpci,uid=7,fid=8,target=hostdev0,id=zpci1 \ > + ... > + > +will be presented in the guest as:: > + > + # lspci -v > + 0007:00:00.0 ... > + Physical Slot: 00000008 > + ... > + > +Finally, note that you might have to enable the ``zpci`` feature in the cpu model in oder to use > +it. I'm wondering what the current state of that feature is -- is it present by default in the newer named models? (My original blog entry was written nearly five years ago ;)