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 1538AC19F2B for ; Thu, 4 Aug 2022 10:17:13 +0000 (UTC) Received: from localhost ([::1]:47526 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oJXuh-00020M-VB for qemu-devel@archiver.kernel.org; Thu, 04 Aug 2022 06:17:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42534) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oJXro-0008D4-8i for qemu-devel@nongnu.org; Thu, 04 Aug 2022 06:14:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:42498) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oJXrl-0004CY-Nf for qemu-devel@nongnu.org; Thu, 04 Aug 2022 06:14:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1659608048; 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=5RVywGVfidpMTyhxOnoRPtdCpV8vkKo7ExIXaORKsq0=; b=BNicYBJU2btEaMq9I19vg3E25jd/qlDmpP4YVcY1IcCW3YPczlGpnuHYGqONOXNmr2GgO7 NKztlv7tMCGFmuJcvvF0RkdppamW262HX+RXbkrFGY/b0GA7BfL8RFRcdgDnrwW0asap9q SpW62CH+WS4uAfS769M+X+I42M++20c= 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-627-inKe8biZMfmYhr1_AI3gDA-1; Thu, 04 Aug 2022 06:14:05 -0400 X-MC-Unique: inKe8biZMfmYhr1_AI3gDA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0BD2A3802B83; Thu, 4 Aug 2022 10:14:05 +0000 (UTC) Received: from localhost (unknown [10.39.193.137]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 92F822166B26; Thu, 4 Aug 2022 10:14:04 +0000 (UTC) From: Cornelia Huck To: Stefan Hajnoczi , qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, Kevin Wolf , Fam Zheng , Amit Shah , Laurent Vivier , Hanna Reitz , "Michael S . Tsirkin" , Stefan Hajnoczi , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Jason Wang , Paolo Bonzini , David Hildenbrand Subject: Re: [PATCH v2 1/2] virtio: document vdc->get_features() callback In-Reply-To: <20220803173606.965926-2-stefanha@redhat.com> Organization: Red Hat GmbH References: <20220803173606.965926-1-stefanha@redhat.com> <20220803173606.965926-2-stefanha@redhat.com> User-Agent: Notmuch/0.36 (https://notmuchmail.org) Date: Thu, 04 Aug 2022 12:14:02 +0200 Message-ID: <87h72s8get.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 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: -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 Wed, Aug 03 2022, Stefan Hajnoczi wrote: > Suggested-by: Cornelia Huck > Signed-off-by: Stefan Hajnoczi > --- > include/hw/virtio/virtio.h | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h > index db1c0ddf6b..8d27fe1824 100644 > --- a/include/hw/virtio/virtio.h > +++ b/include/hw/virtio/virtio.h > @@ -120,9 +120,29 @@ struct VirtioDeviceClass { > /* This is what a VirtioDevice must implement */ > DeviceRealize realize; > DeviceUnrealize unrealize; > + > + /** > + * get_features: > + * @vdev: the VirtIODevice > + * @requested_features: existing device feature bits from > + * vdev->host_features > + * @errp: pointer to error object > + * > + * Get the device feature bits. > + * > + * The ->get_features() function typically sets always-on device feature > + * bits as well as conditional feature bits that require some logic to > + * compute. > + * > + * Device feature bits can also be set in vdev->host_features before this > + * function is called using DEFINE_PROP_BIT64() qdev properties. > + * > + * Returns: the final device feature bits to store in vdev->host_features. > + */ Not sure if we want to go full function doc for features, as none of the other callbacks have it... I thought about something like "Called with vdev->host_features in requested_features. Returns device feature bits to be stored in vdev->host_features after factoring in device-specific feature bits." The important part IMHO is that requested_features contains vdev->host_features, so no need to merge them in. > uint64_t (*get_features)(VirtIODevice *vdev, > uint64_t requested_features, > Error **errp); > + > uint64_t (*bad_features)(VirtIODevice *vdev); > void (*set_features)(VirtIODevice *vdev, uint64_t val); > int (*validate_features)(VirtIODevice *vdev);