From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id C2E96A0540; Fri, 8 Jul 2022 12:39:59 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 85751406B4; Fri, 8 Jul 2022 12:39:59 +0200 (CEST) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mails.dpdk.org (Postfix) with ESMTP id 5167C4021E for ; Fri, 8 Jul 2022 12:39:58 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657276797; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=v7ysSDGIE8oVeIGNMn24EYLNL1RoNPUUpb2PUS5dlpg=; b=hG5wsT0dzAyOvlZ7e5pkvlV3zwVDc1zXB6sKQHPv2f03SFjbI/by60KRym52C2Rn9uFhKA NyuwrAtB4jpmcwj9HuDWuu8bMN6ypYZw4j4axBDLguoIeaKlpwgpj2YJZP9n+haQjvUbPF lkhcH+3J6YUdS3qLvVR3Ol+t0jT87f8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-642-fGw3_jGYPvSvb-zA_9SLtw-1; Fri, 08 Jul 2022 06:39:44 -0400 X-MC-Unique: fGw3_jGYPvSvb-zA_9SLtw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 61AF995B183; Fri, 8 Jul 2022 10:39:44 +0000 (UTC) Received: from [10.39.208.8] (unknown [10.39.208.8]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 787A42026D64; Fri, 8 Jul 2022 10:39:43 +0000 (UTC) Message-ID: Date: Fri, 8 Jul 2022 12:39:42 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH] vdpa/sfc: resolve race between libvhost and dev_conf To: "Saini, Abhimanyu" , "abhimanyu.saini@xilinx.com" , "dev@dpdk.org" Cc: "chenbo.xia@intel.com" , "andrew.rybchenko@oktetlabs.ru" References: <20220706092401.36815-1-asaini@xilinx.com> <4fdc44d3-d9af-88ee-ebc1-7109cc69ce41@redhat.com> From: Maxime Coquelin In-Reply-To: X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=maxime.coquelin@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On 7/8/22 12:25, Saini, Abhimanyu wrote: > [AMD Official Use Only - General] > > Sorry Maxime, I forgot to copy stable. > Yes it's required, the faulty commit is : 630be406dcbfc26260e9d9688c40a381d0f012db Thanks, ammended the commit message and applied to dpdk-next-virtio/main. > > -----Original Message----- > From: Maxime Coquelin > Sent: Friday, July 8, 2022 2:55 PM > To: abhimanyu.saini@xilinx.com; dev@dpdk.org > Cc: chenbo.xia@intel.com; andrew.rybchenko@oktetlabs.ru; Saini, Abhimanyu > Subject: Re: [PATCH] vdpa/sfc: resolve race between libvhost and dev_conf > > [CAUTION: External Email] > > On 7/8/22 11:23, Maxime Coquelin wrote: >> >> >> On 7/6/22 11:24, abhimanyu.saini@xilinx.com wrote: >>> From: Abhimanyu Saini >>> >>> libvhost calls dev_conf() before prosessing the >>> VHOST_USER_SET_VRING_CALL message for the last VQ. So >>> this message is processed after dev_conf() returns. >>> >>> However, the dev_conf() function spawns a thread to set >>> rte_vhost_host_notifier_ctrl() before returning control to >>> libvhost. This parallel thread in turn invokes get_notify_area(). >>> To get the notify_area, the vdpa driver needs to query the HW and >>> for this query it needs an enabled VQ. >>> >>> But at the same time libvhost is processing the last >>> VHOST_USER_SET_VRING_CALL, and to do that it disables the last VQ. >>> >>> Hence there is a race b/w the libvhost and the vdpa driver. >>> >>> To resolve this race condition, query the HW and cache notify_area >>> inside dev_conf() instead of doing it the parallel thread. >>> >>> Signed-off-by: Abhimanyu Saini >>> --- >>> drivers/vdpa/sfc/sfc_vdpa_ops.c | 36 >>> ++++++++++++++++++------------------ >>> drivers/vdpa/sfc/sfc_vdpa_ops.h |  1 + >>> 2 files changed, 19 insertions(+), 18 deletions(-) >>> >> >> Applied to dpdk-next-virtio/main. > > Sorry, I notice it is missing the Fixes tag, and cc'ing stable. > Can you confirm this is needed and provide the faulty commit? > > Thanks, > Maxime > >> Thanks, >> Maxime