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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 7E1F8C433E0 for ; Tue, 2 Mar 2021 16:22:38 +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 EF09664EE4 for ; Tue, 2 Mar 2021 16:22:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EF09664EE4 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]:39920 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lH7nA-0002VV-Te for qemu-devel@archiver.kernel.org; Tue, 02 Mar 2021 11:22:36 -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 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= 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 X-MC-Unique: dzn3_yD7O02TSBulbJieYA-1 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) 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: 8bit Content-Type: text/plain; charset="US-ASCII" 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 --- 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 == 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 = ram_block_discard_disable(true); + if (ret) { + error_report("Cannot set discarding of RAM broken"); + return ret; + } v = opaque; v->dev = dev; @@ -302,6 +313,8 @@ static int vhost_vdpa_cleanup(struct vhost_dev *dev) memory_listener_unregister(&v->listener); dev->opaque = NULL; + ram_block_discard_disable(false); + return 0; } -- 2.29.2