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 X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2AF3C433F5 for ; Wed, 15 Sep 2021 11:16:54 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6E3C960EFF for ; Wed, 15 Sep 2021 11:16:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 6E3C960EFF Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.187506.336388 (Exim 4.92) (envelope-from ) id 1mQSu6-0003w7-Ny; Wed, 15 Sep 2021 11:16:38 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 187506.336388; Wed, 15 Sep 2021 11:16:38 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mQSu6-0003w0-KJ; Wed, 15 Sep 2021 11:16:38 +0000 Received: by outflank-mailman (input) for mailman id 187506; Wed, 15 Sep 2021 11:16:37 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mQSu5-0003tQ-BE for xen-devel@lists.xenproject.org; Wed, 15 Sep 2021 11:16:37 +0000 Received: from smtp-out1.suse.de (unknown [195.135.220.28]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id aef0d088-d611-48ba-b794-2221fe00e3e2; Wed, 15 Sep 2021 11:16:30 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 25B0A2221F; Wed, 15 Sep 2021 11:16:29 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id E6BCB13C37; Wed, 15 Sep 2021 11:16:28 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 7evhNgzWQWEHFAAAMHmgww (envelope-from ); Wed, 15 Sep 2021 11:16:28 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: aef0d088-d611-48ba-b794-2221fe00e3e2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1631704589; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=AjV0yLQDNp7wCmyLlXRUm2R34qvQRC0Ch6O/l5NYfDc=; b=OxfedwDzTzFCJ0byFYdt0blxi/vXV3CzSgJ3/wNV3jzZZvtjKTDJbJEOtaQX91Z1d4EXX8 YFNF0GOcjAzRpvPpPhUQiXIka4YPB/4R4Vfyauk1k1nlqn5lzQde12eNifiqJGDBH+RM0C Gke2pA1mEBRgVzmnU7T0Pzx1Rrxxy3Q= From: Juergen Gross To: minios-devel@lists.xenproject.org, xen-devel@lists.xenproject.org Cc: samuel.thibault@ens-lyon.org, wl@xen.org, Juergen Gross Subject: [PATCH v2] xenbus: support large messages Date: Wed, 15 Sep 2021 13:16:27 +0200 Message-Id: <20210915111627.19486-1-jgross@suse.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Today the implementation of the xenbus protocol in Mini-OS will only allow to transfer the complete message to or from the ring page buffer. This is limiting the maximum message size to lower values as the xenbus protocol normally would allow. Change that by allowing to transfer the xenbus message in chunks as soon as they are available. Avoid crashing Mini-OS in case of illegal data read from the ring buffer. Signed-off-by: Juergen Gross --- V2: - drop redundant if (Samuel Thibault) - move rmb() (Samuel Thibault) --- xenbus/xenbus.c | 211 ++++++++++++++++++++++++++++-------------------- 1 file changed, 123 insertions(+), 88 deletions(-) diff --git a/xenbus/xenbus.c b/xenbus/xenbus.c index 23de61e..ac016e9 100644 --- a/xenbus/xenbus.c +++ b/xenbus/xenbus.c @@ -29,6 +29,7 @@ #include #include #include +#include #define min(x,y) ({ \ typeof(x) tmpx = (x); \ @@ -46,6 +47,7 @@ static struct xenstore_domain_interface *xenstore_buf; static DECLARE_WAIT_QUEUE_HEAD(xb_waitq); DECLARE_WAIT_QUEUE_HEAD(xenbus_watch_queue); +static __DECLARE_SEMAPHORE_GENERIC(xb_write_sem, 1); xenbus_event_queue xenbus_events; static struct watch { @@ -231,75 +233,104 @@ char *xenbus_wait_for_state_change(const char* path, XenbusState *state, xenbus_ } +static void xenbus_read_data(char *buf, unsigned int len) +{ + unsigned int off = 0; + unsigned int prod; + unsigned int size; + int notify; + + while (off != len) + { + wait_event(xb_waitq, xenstore_buf->rsp_prod != xenstore_buf->rsp_cons); + + prod = xenstore_buf->rsp_prod; + DEBUG("Rsp_cons %d, rsp_prod %d.\n", xenstore_buf->rsp_cons, prod); + size = min(len - off, prod - xenstore_buf->rsp_cons); + + rmb(); /* Make sure data read from ring is ordered with rsp_prod. */ + memcpy_from_ring(xenstore_buf->rsp, buf + off, + MASK_XENSTORE_IDX(xenstore_buf->rsp_cons), size); + off += size; + notify = (xenstore_buf->rsp_cons + XENSTORE_RING_SIZE == + xenstore_buf->rsp_prod); + xenstore_buf->rsp_cons += size; + wmb(); + if (notify) + notify_remote_via_evtchn(xenbus_evtchn); + } +} + static void xenbus_thread_func(void *ign) { struct xsd_sockmsg msg; - unsigned prod = xenstore_buf->rsp_prod; + char *data; for (;;) { - wait_event(xb_waitq, prod != xenstore_buf->rsp_prod); - while (1) { - prod = xenstore_buf->rsp_prod; - DEBUG("Rsp_cons %d, rsp_prod %d.\n", xenstore_buf->rsp_cons, - xenstore_buf->rsp_prod); - if (xenstore_buf->rsp_prod - xenstore_buf->rsp_cons < sizeof(msg)) - break; - rmb(); - memcpy_from_ring(xenstore_buf->rsp, &msg, - MASK_XENSTORE_IDX(xenstore_buf->rsp_cons), - sizeof(msg)); - DEBUG("Msg len %d, %d avail, id %d.\n", msg.len + sizeof(msg), - xenstore_buf->rsp_prod - xenstore_buf->rsp_cons, msg.req_id); - - if (xenstore_buf->rsp_prod - xenstore_buf->rsp_cons < - sizeof(msg) + msg.len) - break; - - DEBUG("Message is good.\n"); - - if (msg.type == XS_WATCH_EVENT) { - struct xenbus_event *event = malloc(sizeof(*event) + msg.len); - xenbus_event_queue *events = NULL; - char *data = (char*)event + sizeof(*event); - struct watch *watch; - - memcpy_from_ring(xenstore_buf->rsp, data, - MASK_XENSTORE_IDX(xenstore_buf->rsp_cons + sizeof(msg)), - msg.len); - - event->path = data; - event->token = event->path + strlen(event->path) + 1; - - mb(); - xenstore_buf->rsp_cons += msg.len + sizeof(msg); - - for (watch = watches; watch; watch = watch->next) - if (!strcmp(watch->token, event->token)) { - events = watch->events; - break; - } - - if (events) { - event->next = *events; - *events = event; - wake_up(&xenbus_watch_queue); - } else { - printk("unexpected watch token %s\n", event->token); - free(event); + xenbus_read_data((char *)&msg, sizeof(msg)); + DEBUG("Msg len %d, %d avail, id %d.\n", msg.len + sizeof(msg), + xenstore_buf->rsp_prod - xenstore_buf->rsp_cons, msg.req_id); + + if (msg.len > XENSTORE_PAYLOAD_MAX) { + printk("Xenstore violates protocol, message longer than allowed.\n"); + return; + } + + if (msg.type == XS_WATCH_EVENT) { + struct xenbus_event *event = malloc(sizeof(*event) + msg.len); + xenbus_event_queue *events = NULL; + struct watch *watch; + char *c; + int zeroes = 0; + + data = (char*)event + sizeof(*event); + xenbus_read_data(data, msg.len); + + for (c = data; c < data + msg.len; c++) + if (!*c) + zeroes++; + if (zeroes != 2) { + printk("Xenstore: illegal watch event data\n"); + free(event); + continue; + } + + event->path = data; + event->token = event->path + strlen(event->path) + 1; + + for (watch = watches; watch; watch = watch->next) + if (!strcmp(watch->token, event->token)) { + events = watch->events; + break; } + + if (events) { + event->next = *events; + *events = event; + wake_up(&xenbus_watch_queue); } else { - req_info[msg.req_id].reply = malloc(sizeof(msg) + msg.len); - memcpy_from_ring(xenstore_buf->rsp, req_info[msg.req_id].reply, - MASK_XENSTORE_IDX(xenstore_buf->rsp_cons), - msg.len + sizeof(msg)); - mb(); - xenstore_buf->rsp_cons += msg.len + sizeof(msg); - wake_up(&req_info[msg.req_id].waitq); + printk("Xenstore: unexpected watch token %s\n", event->token); + free(event); } - wmb(); - notify_remote_via_evtchn(xenbus_evtchn); + continue; + } + + data = malloc(sizeof(msg) + msg.len); + memcpy(data, &msg, sizeof(msg)); + xenbus_read_data(data + sizeof(msg), msg.len); + + if (msg.req_id >= NR_REQS || !req_info[msg.req_id].in_use) { + printk("Xenstore: illegal request id %d\n", msg.req_id); + free(data); + continue; } + + DEBUG("Message is good.\n"); + + req_info[msg.req_id].reply = data; + + wake_up(&req_info[msg.req_id].waitq); } } @@ -451,36 +482,40 @@ static void xb_write(int type, int req_id, xenbus_transaction_t trans_id, cur_req = &header_req; - BUG_ON(len > XENSTORE_RING_SIZE); - /* Wait for the ring to drain to the point where we can send the - message. */ - prod = xenstore_buf->req_prod; - if (prod + len - xenstore_buf->req_cons > XENSTORE_RING_SIZE) - { - /* Wait for there to be space on the ring */ - DEBUG("prod %d, len %d, cons %d, size %d; waiting.\n", - prod, len, xenstore_buf->req_cons, XENSTORE_RING_SIZE); - wait_event(xb_waitq, - xenstore_buf->req_prod + len - xenstore_buf->req_cons <= - XENSTORE_RING_SIZE); - DEBUG("Back from wait.\n"); - prod = xenstore_buf->req_prod; - } + BUG_ON(len > XENSTORE_PAYLOAD_MAX); - /* We're now guaranteed to be able to send the message without - overflowing the ring. Do so. */ + /* Make sure we are the only thread trying to write. */ + down(&xb_write_sem); + + /* Send the message in chunks using free ring space when available. */ total_off = 0; req_off = 0; - while (total_off < len) + while (total_off < len) { + prod = xenstore_buf->req_prod; + if (prod - xenstore_buf->req_cons >= XENSTORE_RING_SIZE) + { + /* Send evtchn to notify remote */ + notify_remote_via_evtchn(xenbus_evtchn); + + /* Wait for there to be space on the ring */ + DEBUG("prod %d, len %d, cons %d, size %d; waiting.\n", prod, + len - total_off, xenstore_buf->req_cons, XENSTORE_RING_SIZE); + wait_event(xb_waitq, + prod - xenstore_buf->req_cons < XENSTORE_RING_SIZE); + DEBUG("Back from wait.\n"); + } + this_chunk = min(cur_req->len - req_off, - XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod)); + XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod)); + this_chunk = min(this_chunk, + xenstore_buf->req_cons + XENSTORE_RING_SIZE - prod); memcpy((char *)xenstore_buf->req + MASK_XENSTORE_IDX(prod), - (char *)cur_req->data + req_off, this_chunk); + (char *)cur_req->data + req_off, this_chunk); prod += this_chunk; req_off += this_chunk; total_off += this_chunk; - if (req_off == cur_req->len) + if (req_off == cur_req->len) { req_off = 0; if (cur_req == &header_req) @@ -488,20 +523,20 @@ static void xb_write(int type, int req_id, xenbus_transaction_t trans_id, else cur_req++; } + + /* Remote must see entire message before updating indexes */ + wmb(); + xenstore_buf->req_prod = prod; } + /* Send evtchn to notify remote */ + notify_remote_via_evtchn(xenbus_evtchn); + DEBUG("Complete main loop of xb_write.\n"); BUG_ON(req_off != 0); BUG_ON(total_off != len); - BUG_ON(prod > xenstore_buf->req_cons + XENSTORE_RING_SIZE); - - /* Remote must see entire message before updating indexes */ - wmb(); - - xenstore_buf->req_prod += len; - /* Send evtchn to notify remote */ - notify_remote_via_evtchn(xenbus_evtchn); + up(&xb_write_sem); } /* Send a mesasge to xenbus, in the same fashion as xb_write, and -- 2.26.2