From patchwork Mon Feb 5 17:26:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13545901 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 41BBFC48297 for ; Mon, 5 Feb 2024 17:27:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rX2kU-0008T2-PH; Mon, 05 Feb 2024 12:27:14 -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 1rX2kT-0008SS-6N for qemu-devel@nongnu.org; Mon, 05 Feb 2024 12:27:13 -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 1rX2kR-0006OK-On for qemu-devel@nongnu.org; Mon, 05 Feb 2024 12:27:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1707154030; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Kka7TxXxf07Y0G8FWpyDAIm/nDR/GQGEu5kXBK6b0P8=; b=OI6IKSdvQPB51R0iguTFbmC8cwZL/KXqYDkno/TzCJ9KANydtdC78d6j4VaqGGOFWZAY8r yzX/x0uiOwbnQmdD1VErRVN7Z7bPnNMJnewY8KSD7eFyEganDOvo/k+w8O2heeY0Cd72vW r/PaJ0inqROH6bVgsu4NLTNURY2zmo0= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-357-Q02IBcttM-aduO3i-vy56A-1; Mon, 05 Feb 2024 12:27:06 -0500 X-MC-Unique: Q02IBcttM-aduO3i-vy56A-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8FDE31C05EC0; Mon, 5 Feb 2024 17:27:06 +0000 (UTC) Received: from localhost (unknown [10.39.192.69]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0DFAA492BC6; Mon, 5 Feb 2024 17:27:05 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Kevin Wolf , Hanna Reitz , "Michael S. Tsirkin" , Michael Roth , Markus Armbruster , Stefan Hajnoczi , qemu-block@nongnu.org Subject: [PATCH 2/5] virtio-blk: clarify that there is at least 1 virtqueue Date: Mon, 5 Feb 2024 12:26:56 -0500 Message-ID: <20240205172659.476970-3-stefanha@redhat.com> In-Reply-To: <20240205172659.476970-1-stefanha@redhat.com> References: <20240205172659.476970-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.285, 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, 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-bounces+qemu-devel=archiver.kernel.org@nongnu.org It is not possible to instantiate a virtio-blk device with 0 virtqueues. The following check is located in ->realize(): if (!conf->num_queues) { error_setg(errp, "num-queues property must be larger than 0"); return; } Later on we access s->vq_aio_context[0] under the assumption that there is as least one virtqueue. Hanna Czenczek noted that it would help to show that the array index is already valid. Add an assertion to document that s->vq_aio_context[0] is always safe...and catch future code changes that break this assumption. Suggested-by: Hanna Czenczek Signed-off-by: Stefan Hajnoczi Reviewed-by: Manos Pitsidianakis Reviewed-by: Hanna Czenczek --- hw/block/virtio-blk.c | 1 + 1 file changed, 1 insertion(+) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index e8b37fd5f4..a0735a9bca 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -1825,6 +1825,7 @@ static int virtio_blk_start_ioeventfd(VirtIODevice *vdev) * Try to change the AioContext so that block jobs and other operations can * co-locate their activity in the same AioContext. If it fails, nevermind. */ + assert(nvqs > 0); /* enforced during ->realize() */ r = blk_set_aio_context(s->conf.conf.blk, s->vq_aio_context[0], &local_err); if (r < 0) {