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=-10.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 C7918C433E1 for ; Fri, 24 Jul 2020 04:02:45 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 90C9C20714 for ; Fri, 24 Jul 2020 04:02:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Fxos3acU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 90C9C20714 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33300 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jyouy-0004v2-Qe for qemu-devel@archiver.kernel.org; Fri, 24 Jul 2020 00:02:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38872) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jyosq-0003WO-Dc for qemu-devel@nongnu.org; Fri, 24 Jul 2020 00:00:32 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:24164 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jyosn-0005uO-6E for qemu-devel@nongnu.org; Fri, 24 Jul 2020 00:00:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595563227; 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=1m+QtJyViz6KR5C6aFqYIQ6bSPPAo1REYSpCFB+UmP0=; b=Fxos3acUup5iJHx1nTHwWnBVYMayZyL16i6Q7TcW8jCzvlYY4Y+cBrU0kYrF+Xb9jlqG2F NHoCydhXSnb0cnTtUH9c+tnfHXYl4dFItIS0x2f5krE524GuppI9cn2WuM/CDIMOPOdgG/ e4PMQJA2+mbefojBIcY+5uyGwmEjFVk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-43-jGVmyWbsOpKncft2bXOhPQ-1; Fri, 24 Jul 2020 00:00:21 -0400 X-MC-Unique: jGVmyWbsOpKncft2bXOhPQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BFD118064DE; Fri, 24 Jul 2020 04:00:19 +0000 (UTC) Received: from [10.72.12.225] (ovpn-12-225.pek2.redhat.com [10.72.12.225]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5B91C8BEF4; Fri, 24 Jul 2020 04:00:06 +0000 (UTC) Subject: Re: [PATCH 2/2] e1000e: make TX reentrant To: Peter Maydell References: <20200722085747.6514-1-jasowang@redhat.com> <20200722085747.6514-2-jasowang@redhat.com> From: Jason Wang Message-ID: <67267c28-f706-700a-d1aa-6e5cd8ef0c8d@redhat.com> Date: Fri, 24 Jul 2020 12:00:05 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/24 00:00:27 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Dmitry Fleytman , "Michael S. Tsirkin" , Li Qiang , Li Qiang , QEMU Developers , Alexander Bulekov , Stefan Hajnoczi , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/7/23 下午6:36, Peter Maydell wrote: > On Wed, 22 Jul 2020 at 10:00, Jason Wang wrote: >> In loopback mode, e1000e RX can DMA into TX doorbell which requires >> TX to be reentrant. This patch make e1000e's TX routine reentrant by >> introducing a per device boolean for recording whether or not a TX >> rountine is being called and return early. >> >> Signed-off-by: Jason Wang >> --- > This feels like a sticking-plaster fix that's not really in the > right place... It stops us from calling back into > e1000e_start_xmit(), but it doesn't prevent a DMA request > from touching other device registers that update state in > the E100ECore struct that the transmit code is not expecting > to change. Right, so we can track the mr owner and fail the memory access if there's another mr transaction in memory core: memory_region_dispatch_read() and memory_region_dispatch_write(). But what's more interesting is that some device uses bh for the doorbell which may require more thought... Thanks > > thanks > -- PMM >