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=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,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 417C6C433DB for ; Thu, 4 Mar 2021 09:39:13 +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 C408964E12 for ; Thu, 4 Mar 2021 09:39:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C408964E12 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]:53624 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lHkRr-0004kx-U9 for qemu-devel@archiver.kernel.org; Thu, 04 Mar 2021 04:39:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40806) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lHkQT-00045c-0W for qemu-devel@nongnu.org; Thu, 04 Mar 2021 04:37:45 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:33042) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lHkQR-0000rg-7C for qemu-devel@nongnu.org; Thu, 04 Mar 2021 04:37:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614850661; 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=4b/qGCuoqjPE/6wqhmxJ+LOFBx60XaZ7nYjnHxKtA6M=; b=Hm7/wgab3YUmDHqDQuIKMFRW44TnN2qcdW3jJcdOHqdSxZCQ1+mGxdVwFoK/NbkVWvZoZ3 s7UBwo1v7Vy0oNXHqHDiEzr4fUPFDGI9aDBLxs6BxdYhV/IXZWaXBszfGThUSQtIk554ue xuFhwF37M083FSg+d+WY7s2zXHXIM7c= 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-390-NQJn4t4aO7KyWtrI98iu-g-1; Thu, 04 Mar 2021 04:37:40 -0500 X-MC-Unique: NQJn4t4aO7KyWtrI98iu-g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 347B7108BD0A; Thu, 4 Mar 2021 09:37:39 +0000 (UTC) Received: from wangxiaodeMacBook-Air.local (ovpn-12-64.pek2.redhat.com [10.72.12.64]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5AE741001901; Thu, 4 Mar 2021 09:37:29 +0000 (UTC) Subject: Re: [PATCH v1] vhost-vdpa: Set discarding of RAM broken when initializing the backend To: David Hildenbrand , qemu-devel@nongnu.org, Xie Yongji References: <20210302162129.52912-1-david@redhat.com> <81c675cd-1573-7555-7d20-07b0ed950ebb@redhat.com> <886ed3b7-e48c-7200-e5e6-ce8b0adc589c@redhat.com> <2cd5c10c-0c85-b5a4-de06-30d7ee30661a@redhat.com> From: Jason Wang Message-ID: <58b4e30e-d9ed-395b-2a23-03a04fb58060@redhat.com> Date: Thu, 4 Mar 2021 17:37:27 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.16; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <2cd5c10c-0c85-b5a4-de06-30d7ee30661a@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 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 Content-Language: en-GB Received-SPF: pass client-ip=63.128.21.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: Cindy Lu , "Michael S . Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2021/3/4 5:34 下午, David Hildenbrand wrote: > On 04.03.21 10:32, Jason Wang wrote: >> >> On 2021/3/3 6:26 下午, David Hildenbrand wrote: >>> On 03.03.21 03:53, Jason Wang wrote: >>>> >>>> On 2021/3/3 12:21 上午, David Hildenbrand wrote: >>>>> Similar to VFIO, vDPA will go ahead an map+pin all guest memory. >>>>> Memory >>>>> that used to be discarded will get re-populated and if we >>>>> discard+re-access memory after mapping+pinning, the pages mapped >>>>> into the >>>>> vDPA IOMMU will go out of sync with the actual pages mapped into the >>>>> user >>>>> space page tables. >>>>> >>>>> Set discarding of RAM broken such that: >>>>> - virtio-mem and vhost-vdpa run mutually exclusive >>>>> - virtio-balloon is inhibited and no memory discards will get issued >>>>> >>>>> In the future, we might be able to support coordinated discarding of >>>>> RAM >>>>> as used by virtio-mem and as planned for VFIO. >>>>> >>>>> Cc: Jason Wang >>>>> Cc: Michael S. Tsirkin >>>>> Cc: Cindy Lu >>>>> Signed-off-by: David Hildenbrand >>>> >>>> >>>> Acked-by: Jason Wang >>>> >>>> >>>>> --- >>>>> >>>>> Note: I was not actually able to reproduce/test as I fail to get the >>>>> vdpa_sim/vdpa_sim_net running on upstream Linux (whetever vdpa, >>>>> vhost_vdpa, >>>>> vdpa_sim, vdpa_sim_net modules I probe, and in which order, no vdpa >>>>> devices >>>>> appear under /sys/bus/vdpa/devices/ or /dev/). >>>> >>>> >>>> The device creation was switched to use vdpa tool that is integrated >>>> with iproue2[1]. >>>> >>>> [1] >>>> https://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git/commit/?id=143610383da51e1f868c6d5a2a5e2fb552293d18 >>>> >>>> >>> >>> It would be great to document that somewhere if not already done. I >>> only found older RH documentations that were not aware of that. I'll >>> give it a try - thanks! >> >> >> Will think about this. Which RH doc do you refer here? Is this the >> redhat blog? > > https://www.redhat.com/en/blog/hands-vdpa-what-do-you-do-when-you-aint-got-hardware > > > As it's supposed to be from October 14, 2020 I was surprised to not > get it running (even with older kernels IIRC). Right, the mgmt API is just merged. Will try to see if we can fix the blog. Thanks