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=Qwp0LAwn; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by passt.top (Postfix) with ESMTPS id BDD8E5A029D for ; Wed, 04 Jun 2025 15:09:35 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749042574; 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=2Cb6P2PHGfVtUOCei7wSQl0HeTUnqR6oDbYo/aVnmwc=; b=Qwp0LAwnrtQMqnfWCpWY3jzFnPUDiO6YYYfO1JYbeSWH6ZdT3l0aopmyNnU4APumMUoP4h BVlOS4gtzCUMGJLyziP2wxVXXfN+xI3QwBMaDXsmeQevgVwqWDInKLjyKFsIwWfrbAYpoy fbeEgnhPwYOu03m5+vr2ox0Yy5omrm4= 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-219-tAsiXBy6PDGqRJvTOZg6sQ-1; Wed, 04 Jun 2025 09:09:33 -0400 X-MC-Unique: tAsiXBy6PDGqRJvTOZg6sQ-1 X-Mimecast-MFC-AGG-ID: tAsiXBy6PDGqRJvTOZg6sQ_1749042572 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (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 A957E1801BED for ; Wed, 4 Jun 2025 13:09:32 +0000 (UTC) Received: from lenovo-t14s.redhat.com (unknown [10.45.225.52]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 9577319560AD; Wed, 4 Jun 2025 13:09:31 +0000 (UTC) From: Laurent Vivier To: passt-dev@passt.top Subject: [PATCH v6 30/30] packet: use buf to store iovec array Date: Wed, 4 Jun 2025 15:08:34 +0200 Message-ID: <20250604130834.3868010-31-lvivier@redhat.com> In-Reply-To: <20250604130834.3868010-1-lvivier@redhat.com> References: <20250604130834.3868010-1-lvivier@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 4kmV91EQi-Ct7Vj5tduc4L1zhlUxzmAneei9m2zgaAw_1749042572 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true Message-ID-Hash: 642GZE6JQHFZFY3RBBKTC5P4YVBXSMSG X-Message-ID-Hash: 642GZE6JQHFZFY3RBBKTC5P4YVBXSMSG 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: In vhost-user mode, where `pool->buf` doesn't store packet data directly, this patch repurposes it to hold the `struct iovec` array describing a scattered packet. This enables pools to manage true scatter-gather descriptors, with iovecs pointing to guest memory. `p->pkt[idx].iov_base` is now an index into this `pool->buf` iovec array, and `p->pkt[idx].iov_len` is the count of iovecs. `packet_add_do` uses `iov_tail_slice` to store these iovec descriptors from an input iov_tail into `pool->buf`. `packet_data_do` reconstructs the iov_tail for a packet by pointing to this stored array of iovecs. Signed-off-by: Laurent Vivier --- packet.c | 164 +++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 148 insertions(+), 16 deletions(-) diff --git a/packet.c b/packet.c index fd3b6db57c30..8dbe00af12c6 100644 --- a/packet.c +++ b/packet.c @@ -84,6 +84,122 @@ bool pool_full(const struct pool *p) return p->count >= p->size; } +/** + * packet_iov_max_cnt() - Return the maximum number of iovec entries we can + * store + * @p: Pointer to packet pool + * + * Return: the maximum number of iovec entries we can store in the memory of + * the pool buffer + */ +static size_t packet_iov_max_cnt(const struct pool *p) +{ + return p->buf_size / sizeof(struct iovec); +} + +/** + * packet_iov_idx() - For a given packet index, return the iovec index and + * the number of iovec entry of the packet + * @p: Pointer to packet pool + * @idx: Index of packet descriptor in pool + * @iov_cnt: Pointer to store the number of the iovec entry of the packet + * @func: For tracing: name of calling function + * @line: For tracing: caller line of function call + * + * Return: the iovec index for the given packet index, @iov_cnt is set + * to the number of the iovec entry of the packet + */ +static int packet_iov_idx(const struct pool *p, size_t idx, size_t *iov_cnt, + const char *func, int line) +{ + size_t iov_idx, max = packet_iov_max_cnt(p); + + iov_idx = (size_t)p->pkt[idx].iov_base; + *iov_cnt = p->pkt[idx].iov_len; + + ASSERT_WITH_MSG(iov_idx + *iov_cnt <= max, + "Corrupt iov entry: (%zu, %zu), max: %zu, %s:%i", + iov_idx, *iov_cnt, max, func, line); + + return iov_idx; +} + +/** + * packet_iov_next_idx() - Give the the next available iovec index + * @p: Pointer to packet pool + * @idx: Index of packet descriptor in pool + * @func: For tracing: name of calling function + * @line: For tracing: caller line of function call + * + * Return: the next available iovec index + */ +static size_t packet_iov_next_idx(const struct pool *p, size_t idx, + const char *func, int line) +{ + size_t iov_idx, iov_cnt; + + if (idx == 0) + return 0; + + iov_idx = packet_iov_idx(p, idx - 1, &iov_cnt, func, line); + + return iov_idx + iov_cnt; +} + +/** + * packet_iov_data() - For a given packet index, provide the iovec array + * @p: Pointer to packet pool + * @idx: Index of packet descriptor in pool + * @data: iov_tail to store iovec array and count + * (offset is always set to 0) + * @func: For tracing: name of calling function + * @line: For tracing: caller line of function call + */ +static void packet_iov_data(const struct pool *p, size_t idx, + struct iov_tail *data, + const char *func, int line) +{ + struct iovec *iov = (struct iovec *)p->buf; + size_t iov_idx, iov_cnt; + + iov_idx = packet_iov_idx(p, idx, &iov_cnt, func, line); + + data->iov = &iov[iov_idx]; + data->cnt = iov_cnt; + data->off = 0; +} + +/** + * packet_iov_check_range() - Check if iovec array is valid for a pool + * @p: Pointer to packet pool + * @data: iov_tail that stores the iovec array to check + * @func: For tracing: name of calling function + * @line: For tracing: caller line of function call + * + * Return: 0 if the range is valid, -1 otherwise + */ +static int packet_iov_check_range(const struct pool *p, + const struct iov_tail *data, + const char *func, int line) +{ + size_t offset, i; + + offset = data->off; + for (i = 0; i < data->cnt; i++) { + int ret; + + ret = packet_check_range(p, + (char *)data->iov[i].iov_base + offset, + data->iov[i].iov_len - offset, + func, line); + if (ret) + return ret; + offset = 0; + } + + return 0; +} + /** * packet_add_do() - Add data as packet descriptor to given pool * @p: Existing pool @@ -107,14 +223,32 @@ void packet_add_do(struct pool *p, struct iov_tail *data, if (!iov_tail_prune(data)) return; - ASSERT(data->cnt == 1); /* we don't support iovec */ + if (packet_iov_check_range(p, data, func, line)) + return; + + if (p->memory) { + size_t iov_max_cnt = packet_iov_max_cnt(p); + struct iovec *iov = (struct iovec *)p->buf; + size_t iov_idx; + int iov_cnt; - len = data->iov[0].iov_len - data->off; - start = (char *)data->iov[0].iov_base + data->off; + iov_idx = packet_iov_next_idx(p, idx, func, line); - if (packet_check_range(p, start, len, func, line)) - return; + iov_cnt = iov_tail_clone(&iov[iov_idx], iov_max_cnt - iov_idx, + data); + if (iov_cnt < 0) { + debug("add iov (%zu,%zu) to buf with size %zu, %s:%i", + iov_idx, data->cnt, iov_max_cnt, func, line); + return; + } + len = iov_cnt; + /* NOLINTNEXTLINE(performance-no-int-to-ptr) */ + start = (char *)iov_idx; + } else { + len = data->iov[0].iov_len - data->off; + start = (char *)data->iov[0].iov_base + data->off; + } p->pkt[idx].iov_base = (void *)start; p->pkt[idx].iov_len = len; @@ -136,8 +270,6 @@ bool packet_get_do(const struct pool *p, size_t idx, struct iov_tail *data, const char *func, int line) { - size_t i; - ASSERT_WITH_MSG(p->count <= p->size, "Corrupted pool count: %zu, size: %zu, %s:%i", p->count, p->size, func, line); @@ -148,17 +280,17 @@ bool packet_get_do(const struct pool *p, size_t idx, return false; } - data->cnt = 1; - data->off = 0; - data->iov = &p->pkt[idx]; - - for (i = 0; i < data->cnt; i++) { - ASSERT_WITH_MSG(!packet_check_range(p, data->iov[i].iov_base, - data->iov[i].iov_len, - func, line), - "Corrupt packet pool, %s:%i", func, line); + if (p->memory) { + packet_iov_data(p, idx, data, func, line); + } else { + data->cnt = 1; + data->off = 0; + data->iov = &p->pkt[idx]; } + ASSERT_WITH_MSG(!packet_iov_check_range(p, data, func, line), + "Corrupt packet pool, %s:%i", func, line); + return true; } -- 2.49.0