From patchwork Mon Nov 2 12:17:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 317313 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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 1C4DBC4742C for ; Mon, 2 Nov 2020 12:17:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B9A4620719 for ; Mon, 2 Nov 2020 12:17:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="JDD+P6WT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728740AbgKBMR1 (ORCPT ); Mon, 2 Nov 2020 07:17:27 -0500 Received: from mx2.suse.de ([195.135.220.15]:48138 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728762AbgKBMR1 (ORCPT ); Mon, 2 Nov 2020 07:17:27 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1604319444; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=r8mHf+joyz/0GpLe10Xdqsr1z1obANQBo/Ex5juEWB0=; b=JDD+P6WTIKbS611HGz8GP+KIiyBEfClmKvoob+peQguI4xbrIrW5tPGUYSZuwWUBkGkVuS ha9S1sGkjNAMn7YkZryKOHLNW9xhGhwAjJ0/TGgSf8y9XdAjzDCYJAnJyCOfxY9ldjAQMD 6UMmSowS2pL81vP9IDNE1PX/DFfMGas= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 3419EAF74 for ; Mon, 2 Nov 2020 12:17:24 +0000 (UTC) From: Juergen Gross To: stable@vger.kernel.org Subject: [PATCH 09/14] xen/pvcallsback: use lateeoi irq binding Date: Mon, 2 Nov 2020 13:17:17 +0100 Message-Id: <20201102121722.10940-10-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201102121722.10940-1-jgross@suse.com> References: <20201102121722.10940-1-jgross@suse.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org In order to reduce the chance for the system becoming unresponsive due to event storms triggered by a misbehaving pvcallsfront use the lateeoi irq binding for pvcallsback and unmask the event channel only after handling all write requests, which are the ones coming in via an irq. This requires modifying the logic a little bit to not require an event for each write request, but to keep the ioworker running until no further data is found on the ring page to be processed. This is part of XSA-332. This is upstream commit c8d647a326f06a39a8e5f0f1af946eacfa1835f8 Cc: stable@vger.kernel.org Reported-by: Julien Grall Signed-off-by: Juergen Gross Reviewed-by: Stefano Stabellini Reviewed-by: Wei Liu --- drivers/xen/pvcalls-back.c | 76 +++++++++++++++++++++++--------------- 1 file changed, 46 insertions(+), 30 deletions(-) diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c index 398fd8b1639d..f94bb6034a5a 100644 --- a/drivers/xen/pvcalls-back.c +++ b/drivers/xen/pvcalls-back.c @@ -75,6 +75,7 @@ struct sock_mapping { atomic_t write; atomic_t io; atomic_t release; + atomic_t eoi; void (*saved_data_ready)(struct sock *sk); struct pvcalls_ioworker ioworker; }; @@ -96,7 +97,7 @@ static int pvcalls_back_release_active(struct xenbus_device *dev, struct pvcalls_fedata *fedata, struct sock_mapping *map); -static void pvcalls_conn_back_read(void *opaque) +static bool pvcalls_conn_back_read(void *opaque) { struct sock_mapping *map = (struct sock_mapping *)opaque; struct msghdr msg; @@ -116,17 +117,17 @@ static void pvcalls_conn_back_read(void *opaque) virt_mb(); if (error) - return; + return false; size = pvcalls_queued(prod, cons, array_size); if (size >= array_size) - return; + return false; spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags); if (skb_queue_empty(&map->sock->sk->sk_receive_queue)) { atomic_set(&map->read, 0); spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags); - return; + return true; } spin_unlock_irqrestore(&map->sock->sk->sk_receive_queue.lock, flags); wanted = array_size - size; @@ -150,7 +151,7 @@ static void pvcalls_conn_back_read(void *opaque) ret = inet_recvmsg(map->sock, &msg, wanted, MSG_DONTWAIT); WARN_ON(ret > wanted); if (ret == -EAGAIN) /* shouldn't happen */ - return; + return true; if (!ret) ret = -ENOTCONN; spin_lock_irqsave(&map->sock->sk->sk_receive_queue.lock, flags); @@ -169,10 +170,10 @@ static void pvcalls_conn_back_read(void *opaque) virt_wmb(); notify_remote_via_irq(map->irq); - return; + return true; } -static void pvcalls_conn_back_write(struct sock_mapping *map) +static bool pvcalls_conn_back_write(struct sock_mapping *map) { struct pvcalls_data_intf *intf = map->ring; struct pvcalls_data *data = &map->data; @@ -189,7 +190,7 @@ static void pvcalls_conn_back_write(struct sock_mapping *map) array_size = XEN_FLEX_RING_SIZE(map->ring_order); size = pvcalls_queued(prod, cons, array_size); if (size == 0) - return; + return false; memset(&msg, 0, sizeof(msg)); msg.msg_flags |= MSG_DONTWAIT; @@ -207,12 +208,11 @@ static void pvcalls_conn_back_write(struct sock_mapping *map) atomic_set(&map->write, 0); ret = inet_sendmsg(map->sock, &msg, size); - if (ret == -EAGAIN || (ret >= 0 && ret < size)) { + if (ret == -EAGAIN) { atomic_inc(&map->write); atomic_inc(&map->io); + return true; } - if (ret == -EAGAIN) - return; /* write the data, then update the indexes */ virt_wmb(); @@ -225,9 +225,13 @@ static void pvcalls_conn_back_write(struct sock_mapping *map) } /* update the indexes, then notify the other end */ virt_wmb(); - if (prod != cons + ret) + if (prod != cons + ret) { atomic_inc(&map->write); + atomic_inc(&map->io); + } notify_remote_via_irq(map->irq); + + return true; } static void pvcalls_back_ioworker(struct work_struct *work) @@ -236,6 +240,7 @@ static void pvcalls_back_ioworker(struct work_struct *work) struct pvcalls_ioworker, register_work); struct sock_mapping *map = container_of(ioworker, struct sock_mapping, ioworker); + unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS; while (atomic_read(&map->io) > 0) { if (atomic_read(&map->release) > 0) { @@ -243,10 +248,18 @@ static void pvcalls_back_ioworker(struct work_struct *work) return; } - if (atomic_read(&map->read) > 0) - pvcalls_conn_back_read(map); - if (atomic_read(&map->write) > 0) - pvcalls_conn_back_write(map); + if (atomic_read(&map->read) > 0 && + pvcalls_conn_back_read(map)) + eoi_flags = 0; + if (atomic_read(&map->write) > 0 && + pvcalls_conn_back_write(map)) + eoi_flags = 0; + + if (atomic_read(&map->eoi) > 0 && !atomic_read(&map->write)) { + atomic_set(&map->eoi, 0); + xen_irq_lateeoi(map->irq, eoi_flags); + eoi_flags = XEN_EOI_FLAG_SPURIOUS; + } atomic_dec(&map->io); } @@ -343,12 +356,9 @@ static struct sock_mapping *pvcalls_new_active_socket( goto out; map->bytes = page; - ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id, - evtchn, - pvcalls_back_conn_event, - 0, - "pvcalls-backend", - map); + ret = bind_interdomain_evtchn_to_irqhandler_lateeoi( + fedata->dev->otherend_id, evtchn, + pvcalls_back_conn_event, 0, "pvcalls-backend", map); if (ret < 0) goto out; map->irq = ret; @@ -882,15 +892,18 @@ static irqreturn_t pvcalls_back_event(int irq, void *dev_id) { struct xenbus_device *dev = dev_id; struct pvcalls_fedata *fedata = NULL; + unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS; - if (dev == NULL) - return IRQ_HANDLED; + if (dev) { + fedata = dev_get_drvdata(&dev->dev); + if (fedata) { + pvcalls_back_work(fedata); + eoi_flags = 0; + } + } - fedata = dev_get_drvdata(&dev->dev); - if (fedata == NULL) - return IRQ_HANDLED; + xen_irq_lateeoi(irq, eoi_flags); - pvcalls_back_work(fedata); return IRQ_HANDLED; } @@ -900,12 +913,15 @@ static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map) struct pvcalls_ioworker *iow; if (map == NULL || map->sock == NULL || map->sock->sk == NULL || - map->sock->sk->sk_user_data != map) + map->sock->sk->sk_user_data != map) { + xen_irq_lateeoi(irq, 0); return IRQ_HANDLED; + } iow = &map->ioworker; atomic_inc(&map->write); + atomic_inc(&map->eoi); atomic_inc(&map->io); queue_work(iow->wq, &iow->register_work); @@ -940,7 +956,7 @@ static int backend_connect(struct xenbus_device *dev) goto error; } - err = bind_interdomain_evtchn_to_irq(dev->otherend_id, evtchn); + err = bind_interdomain_evtchn_to_irq_lateeoi(dev->otherend_id, evtchn); if (err < 0) goto error; fedata->irq = err;