From patchwork Wed Jul 31 08:46:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 11067341 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E6AC314DB for ; Wed, 31 Jul 2019 08:47:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D3B6D2886E for ; Wed, 31 Jul 2019 08:47:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C839128872; Wed, 31 Jul 2019 08:47:22 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4B7972886E for ; Wed, 31 Jul 2019 08:47:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 666878E0009; Wed, 31 Jul 2019 04:47:21 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 616628E0001; Wed, 31 Jul 2019 04:47:21 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 505648E0009; Wed, 31 Jul 2019 04:47:21 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) by kanga.kvack.org (Postfix) with ESMTP id 2F2268E0001 for ; Wed, 31 Jul 2019 04:47:21 -0400 (EDT) Received: by mail-qk1-f200.google.com with SMTP id r200so57502069qke.19 for ; Wed, 31 Jul 2019 01:47:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:date:message-id:in-reply-to:references; bh=QiaTlTQOPqg5IgdYAWRREFpZ9TwRpPDQdSyP4YgHR84=; b=oOPAZjZdV/JnA3rnLnv5BASWPtRM9yPgxqi3fP1puMnfs6HphWsCv8W/Vq5VvtG/W9 3j1vFleU+UZhjfEGDIQvRmzQmTY9WPILICGQqT9kj1W+J1MEtVViB19uzYDvGC0X7Ot6 DCP+CDsHzZ5xizzbkWyrJNxOX2b/ItZhNebSLKotjLXS4VAQHNeEh94WAaiCpZKCnWPX JIeNUGxkDvb0vl5KDsa55BlAIVtogIOrAg6rQa8hg6tlZQa1mCThZkgwW1iseqhEdz5i Hj4kCXvmBnH/EKbz/7mTkTO8blDo6QYti0ng5XBjV2ZZAjHEDGbL1IjDr+e+htb6HCZz 4Ndg== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of jasowang@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jasowang@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Gm-Message-State: APjAAAWVxwyXg32LEzxOsE38T887X4D6VQmE2yZ6N11CCyKzTjoD0Bzk CPR/1lgimUXO7nMJFe8p3EOlYg1JLUi4AeNqmWUF5MTq1dHzMhWWeDHQAF0vsreMmeDomBBk8BX mtUbdUzJ32BDiTuBB8aDDif3J9jgSros01Hw6e/Fh+ehegEp08I3KfO1kE975yB+1pQ== X-Received: by 2002:a05:620a:11ac:: with SMTP id c12mr78270811qkk.232.1564562840979; Wed, 31 Jul 2019 01:47:20 -0700 (PDT) X-Google-Smtp-Source: APXvYqxZLxtcM2PjRYkGUxjn7L/vtTP0Ht8rOU8oHSJToA8Z+DXhNPNwUCrX4C0GrTxCleA89OnL X-Received: by 2002:a05:620a:11ac:: with SMTP id c12mr78270786qkk.232.1564562840337; Wed, 31 Jul 2019 01:47:20 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1564562840; cv=none; d=google.com; s=arc-20160816; b=HZMeW/eHgal1ZXAa4VaipYb1OvtjDAcOJY9lL4E5DSmY36ym436rkru00GEj2n0pLw rXnj0gL5hCJGVd3ziLUHRc0F98odW2HVqAJbj7jDwzK54kGbAQNfSkhEQi5lpOnLOnv4 5azTX4bq4y/GyWy3KrQCCuiIxHeaBXhCI8opGJMbwfjzjBoi8nVKm2C0jwIws4w/nytu tMe8Gvj1VUq7FVSKGGXdIeX1m/Qy8swKGgXG6b8qSuZ5zn6GyGbfI7EYCf2oqlqtXtQD x1MWVwZ0UjaJrNqnaSI0r+VH5wEKhWhVaqS5uvyGnketuQCbWfJmvOo2hCK6ap19mfYP S23g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from; bh=QiaTlTQOPqg5IgdYAWRREFpZ9TwRpPDQdSyP4YgHR84=; b=nraJyi7a/cOHEPiNigE4A39uYYCOjQZvp+IJwBtQyIGOz47kq8rqwZ7Ld11ImTJmd3 65t1PzpvvuUwyR1eI7dpjor7bfZxjJlVI4EcP8bUIOfh/CsyukMmVMPJiMgbN2p+6sEV qgEhzlQaK3mXPfCAV6I73jeR5M9CnBbFrhlFUNwv0byQ8N3mqzI78zvaiyL5TB9RZYkB Z1Ta7sNUUvK9M7+GjBqrZr8CduxenC4yuQ5Nhrsvp4pFYEu60PPd3FFGvwQSdTtMcjea Y9sqitwgpknJcAMlaIQyBUu75/Xq3++oPZxF5mwnWh6TDzX6lCxpIuYPjl5slHAs9XP/ sPWg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of jasowang@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jasowang@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id j4si36984043qkm.152.2019.07.31.01.47.20 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 31 Jul 2019 01:47:20 -0700 (PDT) Received-SPF: pass (google.com: domain of jasowang@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of jasowang@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jasowang@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9BF10300CA4E; Wed, 31 Jul 2019 08:47:19 +0000 (UTC) Received: from hp-dl380pg8-01.lab.eng.pek2.redhat.com (hp-dl380pg8-01.lab.eng.pek2.redhat.com [10.73.8.10]) by smtp.corp.redhat.com (Postfix) with ESMTP id E79D3600CC; Wed, 31 Jul 2019 08:47:12 +0000 (UTC) From: Jason Wang To: mst@redhat.com, jasowang@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, jgg@ziepe.ca Subject: [PATCH V2 4/9] vhost: reset invalidate_count in vhost_set_vring_num_addr() Date: Wed, 31 Jul 2019 04:46:50 -0400 Message-Id: <20190731084655.7024-5-jasowang@redhat.com> In-Reply-To: <20190731084655.7024-1-jasowang@redhat.com> References: <20190731084655.7024-1-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Wed, 31 Jul 2019 08:47:19 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP The vhost_set_vring_num_addr() could be called in the middle of invalidate_range_start() and invalidate_range_end(). If we don't reset invalidate_count after the un-registering of MMU notifier, the invalidate_cont will run out of sync (e.g never reach zero). This will in fact disable the fast accessor path. Fixing by reset the count to zero. Reported-by: Michael S. Tsirkin Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual address") Signed-off-by: Jason Wang --- drivers/vhost/vhost.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 2a3154976277..2a7217c33668 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2073,6 +2073,10 @@ static long vhost_vring_set_num_addr(struct vhost_dev *d, d->has_notifier = false; } + /* reset invalidate_count in case we are in the middle of + * invalidate_start() and invalidate_end(). + */ + vq->invalidate_count = 0; vhost_uninit_vq_maps(vq); #endif