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=-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=unavailable 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 5E30FC5519F for ; Tue, 17 Nov 2020 13:18:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A0BE241A6 for ; Tue, 17 Nov 2020 13:18:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="wLi2C8oc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729525AbgKQNQZ (ORCPT ); Tue, 17 Nov 2020 08:16:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:48228 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730298AbgKQNQY (ORCPT ); Tue, 17 Nov 2020 08:16:24 -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 39F3C21734; Tue, 17 Nov 2020 13:16:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605618983; bh=tKRLhmAmFpV4jpSbSuzGdwzL6Or4Y0EdFsh+wENWN8Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wLi2C8ocyhX85AMhEjVxfEmaI8G0RPv0cfYHM2h17PNfbeNs5zY47r92Eoq1f0E3K J92wPIk1N8ZfN0S0+My2ZwTgdWMXPAKzzDq1Bn7MBzM+gthqtAzE3jCiABjf1idQsM Au4xi1TFdCHkOnPOdOlOYxUbYuUCrqx9aR42rWi0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Julien Grall , Juergen Gross , Jan Beulich , Wei Liu Subject: [PATCH 4.14 75/85] xen/scsiback: use lateeoi irq binding Date: Tue, 17 Nov 2020 14:05:44 +0100 Message-Id: <20201117122114.724462969@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201117122111.018425544@linuxfoundation.org> References: <20201117122111.018425544@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Juergen Gross commit 86991b6e7ea6c613b7692f65106076943449b6b7 upstream. In order to reduce the chance for the system becoming unresponsive due to event storms triggered by a misbehaving scsifront use the lateeoi irq binding for scsiback and unmask the event channel only just before leaving the event handling function. In case of a ring protocol error don't issue an EOI in order to avoid the possibility to use that for producing an event storm. This at once will result in no further call of scsiback_irq_fn(), so the ring_error struct member can be dropped and scsiback_do_cmd_fn() can signal the protocol error via a negative return value. This is part of XSA-332. Cc: stable@vger.kernel.org Reported-by: Julien Grall Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Reviewed-by: Wei Liu Signed-off-by: Greg Kroah-Hartman --- drivers/xen/xen-scsiback.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) --- a/drivers/xen/xen-scsiback.c +++ b/drivers/xen/xen-scsiback.c @@ -91,7 +91,6 @@ struct vscsibk_info { unsigned int irq; struct vscsiif_back_ring ring; - int ring_error; spinlock_t ring_lock; atomic_t nr_unreplied_reqs; @@ -721,7 +720,8 @@ static struct vscsibk_pend *prepare_pend return pending_req; } -static int scsiback_do_cmd_fn(struct vscsibk_info *info) +static int scsiback_do_cmd_fn(struct vscsibk_info *info, + unsigned int *eoi_flags) { struct vscsiif_back_ring *ring = &info->ring; struct vscsiif_request ring_req; @@ -738,11 +738,12 @@ static int scsiback_do_cmd_fn(struct vsc rc = ring->rsp_prod_pvt; pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n", info->domid, rp, rc, rp - rc); - info->ring_error = 1; - return 0; + return -EINVAL; } while ((rc != rp)) { + *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS; + if (RING_REQUEST_CONS_OVERFLOW(ring, rc)) break; @@ -801,13 +802,16 @@ static int scsiback_do_cmd_fn(struct vsc static irqreturn_t scsiback_irq_fn(int irq, void *dev_id) { struct vscsibk_info *info = dev_id; + int rc; + unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS; - if (info->ring_error) - return IRQ_HANDLED; - - while (scsiback_do_cmd_fn(info)) + while ((rc = scsiback_do_cmd_fn(info, &eoi_flags)) > 0) cond_resched(); + /* In case of a ring error we keep the event channel masked. */ + if (!rc) + xen_irq_lateeoi(irq, eoi_flags); + return IRQ_HANDLED; } @@ -828,7 +832,7 @@ static int scsiback_init_sring(struct vs sring = (struct vscsiif_sring *)area; BACK_RING_INIT(&info->ring, sring, PAGE_SIZE); - err = bind_interdomain_evtchn_to_irq(info->domid, evtchn); + err = bind_interdomain_evtchn_to_irq_lateeoi(info->domid, evtchn); if (err < 0) goto unmap_page; @@ -1251,7 +1255,6 @@ static int scsiback_probe(struct xenbus_ info->domid = dev->otherend_id; spin_lock_init(&info->ring_lock); - info->ring_error = 0; atomic_set(&info->nr_unreplied_reqs, 0); init_waitqueue_head(&info->waiting_to_free); info->dev = dev;