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 ACDD2C433EF for ; Thu, 23 Jun 2022 08:48:22 +0000 (UTC) Received: from localhost ([::1]:38300 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o4IVh-0008VA-MY for qemu-devel@archiver.kernel.org; Thu, 23 Jun 2022 04:48:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36572) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o4ISM-0006zb-TD for qemu-devel@nongnu.org; Thu, 23 Jun 2022 04:44:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:32040) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o4ISI-0006in-NS for qemu-devel@nongnu.org; Thu, 23 Jun 2022 04:44:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655973890; 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=D2C/xGzcqaWguAIF9BC1lYERda5El5gZBjeZJsmgufI=; b=J/ok1NHJ0sLyuEwjSVKyI00svOlu3UAzG/Mx8+rnuNZ9okXNVEfnkU1UzLiOkkpHS8ZLNs mp42IK7exH6lEjoTqZIKMUojOKzgR5uAl7T09Vy1N20MiWIg2g9XG9BPRPh6RWLgMCJ3dw RXm8U/91eT2EBOuxt8iX2Yp3ge733kM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-124-1vzGPSZBOuiaUVPV8n4lWw-1; Thu, 23 Jun 2022 04:44:47 -0400 X-MC-Unique: 1vzGPSZBOuiaUVPV8n4lWw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A705A80174C; Thu, 23 Jun 2022 08:44:46 +0000 (UTC) Received: from localhost (unknown [10.39.194.10]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 62B8F404E4DC; Thu, 23 Jun 2022 08:44:46 +0000 (UTC) From: Cornelia Huck To: Thomas Huth , qemu-s390x@nongnu.org, Christian Borntraeger , Eric Farman Cc: qemu-devel@nongnu.org Subject: Re: [PATCH 2/2] pc-bios/s390-ccw/virtio: Read device config after feature negotiation In-Reply-To: <20220623071131.412457-3-thuth@redhat.com> Organization: Red Hat GmbH References: <20220623071131.412457-1-thuth@redhat.com> <20220623071131.412457-3-thuth@redhat.com> User-Agent: Notmuch/0.36 (https://notmuchmail.org) Date: Thu, 23 Jun 2022 10:44:45 +0200 Message-ID: <87bkuj93b6.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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" On Thu, Jun 23 2022, Thomas Huth wrote: > Feature negotiation should be done first, since some fields in the > config area can depend on the negotiated features and thus should > rather be read afterwards. I suppose we don't negotiate any features that might affect the size of the config space? Anyway, restricting ourselves to the minimum length should be fine. > > Signed-off-by: Thomas Huth > --- > pc-bios/s390-ccw/virtio.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c > index 4e85a2eb82..0e92e994df 100644 > --- a/pc-bios/s390-ccw/virtio.c > +++ b/pc-bios/s390-ccw/virtio.c > @@ -262,10 +262,6 @@ void virtio_setup_ccw(VDev *vdev) > rc = run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false); > IPL_assert(rc == 0, "Could not write DRIVER status to host"); > > - IPL_assert( > - run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size, false) == 0, > - "Could not get block device configuration"); > - > /* Feature negotiation */ > for (i = 0; i < ARRAY_SIZE(vdev->guest_features); i++) { > feats.features = 0; > @@ -278,6 +274,9 @@ void virtio_setup_ccw(VDev *vdev) > IPL_assert(rc == 0, "Could not set features bits"); > } > > + rc = run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size, false); > + IPL_assert(rc == 0, "Could not get block device configuration"); Since you move this anyway: s/block device/boot device/ ? > + > for (i = 0; i < vdev->nr_vqs; i++) { > VqInfo info = { > .queue = (unsigned long long) ring_area + (i * VIRTIO_RING_SIZE), Related to feature negotiation: It seems that the bios currently supports legacy virtio only, doesn't it? It's probably fine for now, but there might be a way in the future to disable legacy virtio for all devices in QEMU, so we'll probably want to add virtio-1 support some day.