From patchwork Tue Nov 3 20:35:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 316965 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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, 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 85070C388F9 for ; Tue, 3 Nov 2020 21:23:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46170206E3 for ; Tue, 3 Nov 2020 21:23:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604438606; bh=CDHS7acFsmC52HDaJWvOaYyZ9D4HIYMCsSyYx59CVeo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TrgdxY/2+XysP48glqMZgHclHvcZ7B/OaKNUP9kVlvEKblXyGcfZQxDAW8XxwXcCn miZ53k7dDWIHiJaG3uKdakI/KE/ybNy6jNpefG6N1cT96NjiU0olAkDdCVCMx/6raQ +gVIYo1HG5S6lf6YcZtIBXomrNK5nfdualFcIRsE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730562AbgKCVXZ (ORCPT ); Tue, 3 Nov 2020 16:23:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:42686 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729845AbgKCVEf (ORCPT ); Tue, 3 Nov 2020 16:04:35 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4109E205ED; Tue, 3 Nov 2020 21:04:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604437474; bh=CDHS7acFsmC52HDaJWvOaYyZ9D4HIYMCsSyYx59CVeo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2LL/Rn+NSzKjWhP6lAYXUBG6XBJAitiObmKvs3PGUGWnvSpJ7JOfaaOB6Gz7YJ1Ei TvxZ/3lsac2ncUGcVuYnuZViojT39bCGG8IT/rB3BqMYCnsM0YgtFkP6PrElVDrW3C y6T+6bP2Kwr0f2+rq6iFQDbojXcv2xtUQErUopRs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Julien Grall , Juergen Gross , Stefano Stabellini , Wei Liu Subject: [PATCH 4.19 044/191] xen/pvcallsback: use lateeoi irq binding Date: Tue, 3 Nov 2020 21:35:36 +0100 Message-Id: <20201103203238.403049689@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201103203232.656475008@linuxfoundation.org> References: <20201103203232.656475008@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Juergen Gross commit c8d647a326f06a39a8e5f0f1af946eacfa1835f8 upstream. 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. Cc: stable@vger.kernel.org Reported-by: Julien Grall Signed-off-by: Juergen Gross Reviewed-by: Stefano Stabellini Reviewed-by: Wei Liu Signed-off-by: Greg Kroah-Hartman --- drivers/xen/pvcalls-back.c | 76 +++++++++++++++++++++++++++------------------ 1 file changed, 46 insertions(+), 30 deletions(-) --- 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(s 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 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 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 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(stru 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(stru 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(stru } /* 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 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 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_ 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(in { 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_eve 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 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;