From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: passt.top; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=Oo5vU2UN; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTPS id DF9765A0262 for ; Mon, 09 Mar 2026 10:48:11 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773049690; 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=92k7t6Y/m/L6mIZtMeM6rUn2kJnZnYIecYgRSwHLKlk=; b=Oo5vU2UNRFnmRytyKRXWLe10bKVzAw3+rBFnj9WMzETpbCPUHzYu2jIAOWmL8pZIxlwZ/8 0Bzs3wwiGLMQDm4KupHD2vUel1gtEzRzbi7+U2LboHHbnhZJzBlHFe/gMS3qty1aOMzFDi 4p61AEetQ/v1RjSbmyyUNbNVozWGZO8= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-676-YrAjbSj4PvqWL2bFwHFvTw-1; Mon, 09 Mar 2026 05:48:09 -0400 X-MC-Unique: YrAjbSj4PvqWL2bFwHFvTw-1 X-Mimecast-MFC-AGG-ID: YrAjbSj4PvqWL2bFwHFvTw_1773049688 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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 mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8B9CD1800464 for ; Mon, 9 Mar 2026 09:48:08 +0000 (UTC) Received: from lenovo-t14s.redhat.com (unknown [10.45.226.4]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 8FAB51956095; Mon, 9 Mar 2026 09:48:07 +0000 (UTC) From: Laurent Vivier To: passt-dev@passt.top Subject: [PATCH v2 13/13] vhost-user,udp: Use 2 iovec entries per element Date: Mon, 9 Mar 2026 10:47:44 +0100 Message-ID: <20260309094744.1907754-14-lvivier@redhat.com> In-Reply-To: <20260309094744.1907754-1-lvivier@redhat.com> References: <20260309094744.1907754-1-lvivier@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: AC8w-ODmlgfYcFleHtXeFNWBm3sWWnYDZ53ZPlGPnRM_1773049688 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true Message-ID-Hash: 7XUQJJSECCHAAYAAFNWUANGB2PQTGVXB X-Message-ID-Hash: 7XUQJJSECCHAAYAAFNWUANGB2PQTGVXB X-MailFrom: lvivier@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: Laurent Vivier X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: iPXE places the vnet header in one virtqueue descriptor and the payload in another. When passt maps these descriptors, it needs two iovecs per virtqueue element to handle this layout. Without this, passt crashes with: ASSERTION FAILED in virtqueue_map_desc (virtio.c:403): num_sg < max_num_sg Signed-off-by: Laurent Vivier --- udp_vu.c | 8 ++++---- vu_common.c | 15 +++++++++++---- 2 files changed, 15 insertions(+), 8 deletions(-) diff --git a/udp_vu.c b/udp_vu.c index cb5274aa1d81..47659b0402fd 100644 --- a/udp_vu.c +++ b/udp_vu.c @@ -34,7 +34,7 @@ #include "vu_common.h" static struct iovec iov_vu [VIRTQUEUE_MAX_SIZE]; -static struct vu_virtq_element elem [VIRTQUEUE_MAX_SIZE]; +static struct vu_virtq_element elem [VIRTQUEUE_MAX_SIZE / IOV_PER_ELEM]; /** * udp_vu_hdrlen() - Sum size of all headers, from UDP to virtio-net @@ -214,20 +214,20 @@ void udp_vu_sock_to_tap(const struct ctx *c, int s, int n, flow_sidx_t tosidx) size_t iov_cnt; ssize_t dlen; - vu_init_elem(elem, iov_vu, ARRAY_SIZE(elem), 1); + vu_init_elem(elem, iov_vu, ARRAY_SIZE(elem), IOV_PER_ELEM); elem_cnt = vu_collect(vdev, vq, elem, ARRAY_SIZE(elem), IP_MAX_MTU + ETH_HLEN + VNET_HLEN, NULL); if (elem_cnt == 0) break; - iov_cnt = elem_cnt; + iov_cnt = (size_t)elem_cnt * IOV_PER_ELEM; dlen = udp_vu_sock_recv(iov_vu, &iov_cnt, s, v6); if (dlen < 0) { vu_queue_rewind(vq, elem_cnt); break; } - elem_used = iov_cnt; + elem_used = DIV_ROUND_UP(iov_cnt, IOV_PER_ELEM); /* release unused buffers */ vu_queue_rewind(vq, elem_cnt - elem_used); diff --git a/vu_common.c b/vu_common.c index 3225aca53ea6..a2867a293184 100644 --- a/vu_common.c +++ b/vu_common.c @@ -63,8 +63,15 @@ void vu_init_elem(struct vu_virtq_element *elem, struct iovec *iov, { int i, j; - for (i = 0, j = 0; i < elem_cnt; i++, j += iov_per_elem) + for (i = 0, j = 0; i < elem_cnt; i++, j += iov_per_elem) { + int k; + + for (k = 0; k < iov_per_elem; k++) { + iov[j + k].iov_base = NULL; + iov[j + k].iov_len = 0; + } vu_set_element(&elem[i], 0, NULL, iov_per_elem, &iov[j]); + } } /** @@ -272,7 +279,7 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size) { struct vu_dev *vdev = c->vdev; struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE]; - struct vu_virtq_element elem[VIRTQUEUE_MAX_SIZE]; + struct vu_virtq_element elem[VIRTQUEUE_MAX_SIZE / IOV_PER_ELEM]; struct iovec in_sg[VIRTQUEUE_MAX_SIZE]; struct iov_tail data; size_t total; @@ -286,7 +293,7 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size) return -1; } - vu_init_elem(elem, in_sg, ARRAY_SIZE(elem), 1); + vu_init_elem(elem, in_sg, ARRAY_SIZE(elem), IOV_PER_ELEM); size += VNET_HLEN; elem_cnt = vu_collect(vdev, vq, elem, ARRAY_SIZE(elem), size, &total); @@ -303,7 +310,7 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size) } elem_cnt = iov_truncate(in_sg, elem_cnt, size); - data = IOV_TAIL(&in_sg[0], elem_cnt, 0); + data = IOV_TAIL(&in_sg[0], (size_t)(elem_cnt * IOV_PER_ELEM), 0); vu_set_vnethdr(&data, elem_cnt); size -= VNET_HLEN; -- 2.53.0