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bh=ZSKRmVm70sbawPnc3LB1RgSk9cDzZ9crgmPEQfxf4xc=; b=T0T5Waku4PlL4mFQBdGA96KER28Bl+Df8h4/yHJ1qF3gZ97NAqrjXqNY6w0uNi39R7YT5H ofj7pWGGfYMLvPxlyooStEdSjtyfo/BiqPqEZReGuCeF5Oiv4NyKYlm/gQdKe2guFem8QR NZbTx8hkKrKFTiR41+B8c67Zie7Pq2Y= X-MC-Unique: I_kEr9VJN4SKqv-zij_O6Q-1 From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, qemu-devel@nongnu.org Subject: [PULL 02/16] virtio-blk: clarify that there is at least 1 virtqueue Date: Wed, 7 Feb 2024 22:55:52 +0100 Message-ID: <20240207215606.206038-3-kwolf@redhat.com> In-Reply-To: <20240207215606.206038-1-kwolf@redhat.com> References: <20240207215606.206038-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.106, 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_H5=0.001, RCVD_IN_MSPIKE_WL=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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1707343058097100001 Content-Type: text/plain; charset="utf-8" From: Stefan Hajnoczi 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 Reviewed-by: Manos Pitsidianakis Reviewed-by: Hanna Czenczek Signed-off-by: Stefan Hajnoczi Message-ID: <20240206190610.107963-3-stefanha@redhat.com> Reviewed-by: Kevin Wolf Reviewed-by: Michael S. Tsirkin Signed-off-by: Kevin Wolf --- 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 6e3e3a23ee..e430ba583c 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -1824,6 +1824,7 @@ static int virtio_blk_start_ioeventfd(VirtIODevice *v= dev) * Try to change the AioContext so that block jobs and other operation= s can * co-locate their activity in the same AioContext. If it fails, never= mind. */ + assert(nvqs > 0); /* enforced during ->realize() */ r =3D blk_set_aio_context(s->conf.conf.blk, s->vq_aio_context[0], &local_err); if (r < 0) { --=20 2.43.0