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=-10.1 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,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C9660C433E0 for ; Mon, 28 Dec 2020 08:45:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8362B208B6 for ; Mon, 28 Dec 2020 08:45:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726475AbgL1IpL (ORCPT ); Mon, 28 Dec 2020 03:45:11 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:42079 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726282AbgL1IpL (ORCPT ); Mon, 28 Dec 2020 03:45:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1609145024; 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=b/mQcN8HBMjEvpA5cui1zWJDGM1GYmpavHlrRlsXqE4=; b=BHjOHyXqPdygAdIgXCxlEtCC4AfmlPs2v4wJqaDYdJJ/mAo0fyRDeaDFk2m5jBnHpaycWk L3UZtQg4BfxWTMWakupEPKpJ/LLniAhiRYMC+18wyRHCJ61MBEMf77OJnENHqBzY29EF3c pOpWKaHdmm1PfeeyjniWES9vXcSf/Eg= 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-517-fgpg1Q3MMjmXbi0k5uLn9w-1; Mon, 28 Dec 2020 03:43:40 -0500 X-MC-Unique: fgpg1Q3MMjmXbi0k5uLn9w-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id D532A800D53; Mon, 28 Dec 2020 08:43:37 +0000 (UTC) Received: from [10.72.13.159] (ovpn-13-159.pek2.redhat.com [10.72.13.159]) by smtp.corp.redhat.com (Postfix) with ESMTP id AEDAC704DA; Mon, 28 Dec 2020 08:43:19 +0000 (UTC) Subject: Re: [RFC v2 09/13] vduse: Add support for processing vhost iotlb message To: Yongji Xie Cc: "Michael S. Tsirkin" , Stefan Hajnoczi , sgarzare@redhat.com, Parav Pandit , akpm@linux-foundation.org, Randy Dunlap , Matthew Wilcox , viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org, corbet@lwn.net, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org References: <20201222145221.711-1-xieyongji@bytedance.com> <20201222145221.711-10-xieyongji@bytedance.com> <6818a214-d587-4f0b-7de6-13c4e7e94ab6@redhat.com> <595fe7d6-7876-26e4-0b7c-1d63ca6d7a97@redhat.com> <0e6faf9c-117a-e23c-8d6d-488d0ec37412@redhat.com> <2b24398c-e6d9-14ec-2c0d-c303d528e377@redhat.com> From: Jason Wang Message-ID: Date: Mon, 28 Dec 2020 16:43:18 +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-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2020/12/28 下午4:14, Yongji Xie wrote: >> I see. So all the above two questions are because VHOST_IOTLB_INVALIDATE >> is expected to be synchronous. This need to be solved by tweaking the >> current VDUSE API or we can re-visit to go with descriptors relaying first. >> > Actually all vdpa related operations are synchronous in current > implementation. The ops.set_map/dma_map/dma_unmap should not return > until the VDUSE_UPDATE_IOTLB/VDUSE_INVALIDATE_IOTLB message is replied > by userspace. Could it solve this problem?  I was thinking whether or not we need to generate IOTLB_INVALIDATE message to VDUSE during dma_unmap (vduse_dev_unmap_page). If we don't, we're probably fine. Thanks > > Thanks, > Yongji >