From nobody Sun Feb 8 12:17:01 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1614702161; cv=none; d=zohomail.com; s=zohoarc; b=iH/f/7J1Ysgst9l2S7CdaMOiYMAx88162qzgBl7cVtyCY+NkW7OaUtusbXGMOnBxLmLoYvQf3pa8K4+ATVRiRS6OtC2XiDzXikweP5cjpcAItuNMmOL76GYiUEkThAAGwokRoGRf0xuqmCCzNUmKQBJaYS/Mysw+53GLtbG5UYI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1614702161; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=lCixjWvBHCGvMqpyREzWDiX2gmEDYj6mB/wyHquz0pc=; b=HDt3D/XTFojd3KE+c6V7s/AmqLaWDyLChxtrpARQJ2kaX4ykRi4eY0iZlbIe1KEcx5opAGqJoaWMXvM8QC9D9k4BnNRXIXO2mc3v9UKChnTGOq2br6ZlpMff/N0KNOS2yljDf1KmRIu0P8z+0bYsYSBfecHAxxgbQ5odexNBmUQ= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1614702161050547.2275081754292; Tue, 2 Mar 2021 08:22:41 -0800 (PST) Received: from localhost ([::1]:39920 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lH7nD-0002VV-8m for importer@patchew.org; Tue, 02 Mar 2021 11:22:39 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34798) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lH7mP-00020M-Sd for qemu-devel@nongnu.org; Tue, 02 Mar 2021 11:21:49 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:60964) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lH7mN-0000jI-E0 for qemu-devel@nongnu.org; Tue, 02 Mar 2021 11:21:49 -0500 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-347-dzn3_yD7O02TSBulbJieYA-1; Tue, 02 Mar 2021 11:21:42 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3F23385B667 for ; Tue, 2 Mar 2021 16:21:41 +0000 (UTC) Received: from t480s.redhat.com (ovpn-114-189.ams2.redhat.com [10.36.114.189]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1A1E15DEF8; Tue, 2 Mar 2021 16:21:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614702106; 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; bh=lCixjWvBHCGvMqpyREzWDiX2gmEDYj6mB/wyHquz0pc=; b=NlGKejv6YuDnvQywenxMQVhawensSquBaU++1/1pEn2ZVrTDNBx55muZ/0E6e7LoEwz+Rk tN3gQmeZkAzhLsmgQ27AtaaTbbF+KzJI7iCEFURAdnwkIOHsImYobPfBazvtQ/yu3Y9tbf q3Lgzr/pz1MQXAiCC9yQVLDag92NZxc= X-MC-Unique: dzn3_yD7O02TSBulbJieYA-1 From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v1] vhost-vdpa: Set discarding of RAM broken when initializing the backend Date: Tue, 2 Mar 2021 17:21:29 +0100 Message-Id: <20210302162129.52912-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=216.205.24.124; envelope-from=david@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, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=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: Jason Wang , "Michael S . Tsirkin" , Cindy Lu , David Hildenbrand Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" 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/). --- hw/virtio/vhost-vdpa.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index 01d2101d09..86058d4041 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c @@ -278,6 +278,17 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void= *opaque) uint64_t features; assert(dev->vhost_ops->backend_type =3D=3D VHOST_BACKEND_TYPE_VDPA); trace_vhost_vdpa_init(dev, opaque); + int ret; + + /* + * Similar to VFIO, we end up pinning all guest memory and have to + * disable discarding of RAM. + */ + ret =3D ram_block_discard_disable(true); + if (ret) { + error_report("Cannot set discarding of RAM broken"); + return ret; + } =20 v =3D opaque; v->dev =3D dev; @@ -302,6 +313,8 @@ static int vhost_vdpa_cleanup(struct vhost_dev *dev) memory_listener_unregister(&v->listener); =20 dev->opaque =3D NULL; + ram_block_discard_disable(false); + return 0; } =20 --=20 2.29.2