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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 46775C38A24 for ; Thu, 7 May 2020 15:49:32 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 140452082E for ; Thu, 7 May 2020 15:49:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IM5V9wda" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 140452082E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48844 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jWimB-0007Ye-7e for qemu-devel@archiver.kernel.org; Thu, 07 May 2020 11:49:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33204) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jWiki-0006uA-9l for qemu-devel@nongnu.org; Thu, 07 May 2020 11:48:00 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:49133 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jWikh-0003xU-45 for qemu-devel@nongnu.org; Thu, 07 May 2020 11:48:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588866477; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BnJec2M5KIfTKxnmSUe6nsimepltb7ggMe3V8Jzyrso=; b=IM5V9wdaAEy3VZicji1gY06VUWhBUUsqbOPAnDOm+o1c89ukD6JavQaWArH51LvG8xb8De ea9AEhSE6SPWYKXK/hBD+e/Ejj66WIaqPdc6gwGm1af3R2oU6wsP5N3gI1jj+Xn6Umtjdr nCtvI2JBq03xoKmyn/j0YN6D70Mswns= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-170-QYRb74I6P7meYpFtZy-nLg-1; Thu, 07 May 2020 11:47:53 -0400 X-MC-Unique: QYRb74I6P7meYpFtZy-nLg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 748FB835B41; Thu, 7 May 2020 15:47:52 +0000 (UTC) Received: from [10.3.114.73] (ovpn-114-73.phx2.redhat.com [10.3.114.73]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2F01A2BFCC; Thu, 7 May 2020 15:47:34 +0000 (UTC) Subject: Re: [RFC v3 3/6] qmp: decode feature bits in virtio-status To: Laurent Vivier , qemu-devel@nongnu.org References: <20200507114927.6733-1-lvivier@redhat.com> <20200507114927.6733-4-lvivier@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: Date: Thu, 7 May 2020 10:47:33 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200507114927.6733-4-lvivier@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=eblake@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/07 03:15:48 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] 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_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , Kevin Wolf , Thomas Huth , qemu-block@nongnu.org, David Hildenbrand , Markus Armbruster , Jason Wang , "Michael S. Tsirkin" , Michael Roth , Amit Shah , Max Reitz , Eric Auger , Gerd Hoffmann , Stefan Hajnoczi , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , Paolo Bonzini , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/7/20 6:49 AM, Laurent Vivier wrote: > Display feature names instead of a features bitmap for host, guest > and backend. > > Decode features according device type, transport features are > on the first line. Undecoded bits (if any) are stored in a separate > field. > > Signed-off-by: Laurent Vivier > --- I didn't closely review the code, but for the QAPI parts: > +++ b/qapi/virtio.json > +## > +# @VirtioBlkFeature: > +# > +# An enumeration of Virtio block features > +# > +# Since: 5.1 > +## > + > +{ 'enum': 'VirtioBlkFeature', > + 'data': [ 'size-max', 'seg-max', 'geometry', 'ro', 'blk-size', 'topology', 'mq', 'discard', 'write-zeroes', 'barrier', 'scsi', 'flush', Missing newline. > +## > +# @VirtioDeviceFeatures: > +# > +# An union to define the list of features for a virtio device s/An/A/ (in English, 'an' goes with soft u, 'a' goes with pronounced u. You can remember with "a unicorn gets an umbrella") > +# > +# Since: 5.1 > +## > + > +{ 'union': 'VirtioDeviceFeatures', > + 'data': { > + 'virtio-serial': [ 'VirtioSerialFeature' ], > + 'virtio-blk': [ 'VirtioBlkFeature' ], > + 'virtio-gpu': [ 'VirtioGpuFeature' ], > + 'virtio-net': [ 'VirtioNetFeature' ], > + 'virtio-scsi': [ 'VirtioScsiFeature' ], > + 'virtio-balloon': [ 'VirtioBalloonFeature' ], > + 'virtio-iommu': [ 'VirtioIommuFeature' ] > + } > +} This is a legacy union rather than a flat union, which results in more {} in the QMP wire format. Is it worth trying to make this a flat union, by labeling an appropriate member as 'discriminator'? > + > +## > +# @VirtioStatusFeatures: > +# > +# @transport: the list of transport features of the virtio device > +# > +# @device: the list of the virtio device specific features > +# > +# @unknown: virtio bitmap of the undecoded features > +# > +# Since: 5.1 > +## > + > +{ 'struct': 'VirtioStatusFeatures', > + 'data': { 'transport': [ 'VirtioTransportFeature' ], > + 'device': 'VirtioDeviceFeatures', > + 'unknown': 'uint64' } > +} > + > ## > # @VirtioStatus: > # > @@ -101,9 +245,9 @@ > 'data': { > 'device-id': 'int', > 'device-endian': 'VirtioStatusEndianness', > - 'guest-features': 'uint64', > - 'host-features': 'uint64', > - 'backend-features': 'uint64', > + 'guest-features': 'VirtioStatusFeatures', > + 'host-features': 'VirtioStatusFeatures', > + 'backend-features': 'VirtioStatusFeatures', This is intra-series churn. Should we be trying to get the right types in place from the get-go? Or at least clarify in the commit message of the earlier patch that the format will be incrementally improved later? > 'num-vqs': 'uint16' > } > } > @@ -123,18 +267,40 @@ > # > # -> { "execute": "x-debug-virtio-status", > # "arguments": { > -# "path": "/machine/peripheral-anon/device[3]/virtio-backend" > +# "path": "/machine/peripheral-anon/device[1]/virtio-backend" > # } > # } > # <- { "return": { > -# "backend-features": 0, > -# "guest-features": 5111807911, > -# "num-vqs": 3, > -# "host-features": 6337593319, > # "device-endian": "little", > -# "device-id": 1 > +# "device-id": 3, > +# "backend-features": { > +# "device": { > +# "type": "virtio-serial", > +# "data": [] > +# }, > +# "unknown": 0, > +# "transport": [] > +# }, If we use a flat union, this could look like: "backend-feature": { "type": "virtio-serial", "features": [], "unknown": 0, "transport": [] }, Should 'unknown' be optional so it can be omitted when zero? Should it be named 'unknown-features'? -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org