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 42836C7619A for ; Mon, 27 Mar 2023 12:56:26 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pgmO6-00070a-LG; Mon, 27 Mar 2023 08:55:50 -0400 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 1pgmO4-00070J-K7 for qemu-devel@nongnu.org; Mon, 27 Mar 2023 08:55:48 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pgmO2-00010s-5Z for qemu-devel@nongnu.org; Mon, 27 Mar 2023 08:55:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679921744; 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=ADsJEH7OZjFH3jx0VY8y8j0YlllWKWQn9UaL5ZuDTes=; b=Wailoi2IcyIKLVy6EgV6BoHuyGV/gKMlM2Ps37sPRaAXeOjXBf4QaHgtBXQ8rG5f3tiDn1 sBU6fOgnD/QtxjYTIDTPwwNXD9YAIcafANYdWCPuTK84fNYBziXePRSgSHNTrOl96GH/r1 4ifYsBZJs9j9Tu27FSfWejpP4clzqh0= 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-172-wmSONA2EOnCjzsSAsGQ44g-1; Mon, 27 Mar 2023 08:55:41 -0400 X-MC-Unique: wmSONA2EOnCjzsSAsGQ44g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E2D861C09501; Mon, 27 Mar 2023 12:55:40 +0000 (UTC) Received: from localhost (unknown [10.39.193.145]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 866AF202701E; Mon, 27 Mar 2023 12:55:40 +0000 (UTC) From: Cornelia Huck To: Carlos =?utf-8?Q?L=C3=B3pez?= , qemu-devel@nongnu.org Cc: Carlos =?utf-8?Q?L=C3=B3pez?= , "Michael S. Tsirkin" , Halil Pasic , Eric Farman , Richard Henderson , David Hildenbrand , Ilya Leoshkevich , Christian Borntraeger , Thomas Huth , "open list:virtio-ccw" Subject: Re: [PATCH v2] virtio: refresh vring region cache after updating a virtqueue size In-Reply-To: <20230317002749.27379-1-clopez@suse.de> Organization: Red Hat GmbH References: <20230317002749.27379-1-clopez@suse.de> User-Agent: Notmuch/0.37 (https://notmuchmail.org) Date: Mon, 27 Mar 2023 14:55:38 +0200 Message-ID: <87zg7yqrp1.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 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: -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, Mar 17 2023, Carlos L=C3=B3pez wrote: > When a virtqueue size is changed by the guest via > virtio_queue_set_num(), its region cache is not automatically updated. > If the size was increased, this could lead to accessing the cache out > of bounds. For example, in vring_get_used_event(): > > static inline uint16_t vring_get_used_event(VirtQueue *vq) > { > return vring_avail_ring(vq, vq->vring.num); > } > > static inline uint16_t vring_avail_ring(VirtQueue *vq, int i) > { > VRingMemoryRegionCaches *caches =3D vring_get_region_caches(vq); > hwaddr pa =3D offsetof(VRingAvail, ring[i]); > > if (!caches) { > return 0; > } > > return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); > } > > vq->vring.num will be greater than caches->avail.len, which will > trigger a failed assertion down the call path of > virtio_lduw_phys_cached(). > > Fix this by calling virtio_init_region_cache() after > virtio_queue_set_num() if we are not already calling > virtio_queue_set_rings(). In the legacy path this is already done by > virtio_queue_update_rings(). > > Signed-off-by: Carlos L=C3=B3pez > --- > v2: use virtio_init_region_cache() instead of > virtio_queue_update_rings() in the path for modern devices. > > hw/s390x/virtio-ccw.c | 1 + > hw/virtio/virtio-mmio.c | 1 + > hw/virtio/virtio-pci.c | 1 + > hw/virtio/virtio.c | 2 +- > include/hw/virtio/virtio.h | 1 + > 5 files changed, 5 insertions(+), 1 deletion(-) > Reviewed-by: Cornelia Huck We can always do any ccw reshuffling on top.