From patchwork Thu Dec 22 11:02:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13079582 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 32072C001B2 for ; Thu, 22 Dec 2022 11:06:42 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p8JLM-0007or-My; Thu, 22 Dec 2022 06:02:32 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p8JLK-0007lu-Ii for qemu-devel@nongnu.org; Thu, 22 Dec 2022 06:02:30 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p8JLI-0000dx-M8 for qemu-devel@nongnu.org; Thu, 22 Dec 2022 06:02:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1671706948; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xvQizLOJBawnOU2rcD7C8fqld3+IuUMt32YPNXyAFrA=; b=FBmawrugMrsEHweO4zgYO+p5lZfopynYO3S13c5sY0HFxUc65Sph7OJDVU7hW7esKc+IiA I/GZzPMYQrSo6zjuB735gyoMpzXPoiGS+32TcOCW2vBUcU6U6ah210uC5MDpPAymovi8G2 rBJZEB7LIbOE0nnjUKJeLYIZOKTK+zw= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-552-n-yg1uBUNiSZis6ufD890w-1; Thu, 22 Dec 2022 06:02:26 -0500 X-MC-Unique: n-yg1uBUNiSZis6ufD890w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4F6F43806079 for ; Thu, 22 Dec 2022 11:02:26 +0000 (UTC) Received: from t480s.fritz.box (unknown [10.39.193.53]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0728214152F4; Thu, 22 Dec 2022 11:02:24 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: David Hildenbrand , "Dr . David Alan Gilbert" , Juan Quintela , Peter Xu , "Michael S . Tsirkin" , Michal Privoznik Subject: [PATCH v3 4/6] virtio-mem: Fail if a memory backend with "prealloc=on" is specified Date: Thu, 22 Dec 2022 12:02:13 +0100 Message-Id: <20221222110215.130392-5-david@redhat.com> In-Reply-To: <20221222110215.130392-1-david@redhat.com> References: <20221222110215.130392-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org "prealloc=on" for the memory backend does not work as expected, as virtio-mem will simply discard all preallocated memory immediately again. In the best case, it's an expensive NOP. In the worst case, it's an unexpected allocation error. Instead, "prealloc=on" should be specified for the virtio-mem device only, such that virtio-mem will try preallocating memory before plugging memory dynamically to the guest. Fail if such a memory backend is provided. Tested-by: Michal Privoznik Signed-off-by: David Hildenbrand --- hw/virtio/virtio-mem.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index 5c22c4b876..e0e908d392 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -772,6 +772,12 @@ static void virtio_mem_device_realize(DeviceState *dev, Error **errp) error_setg(errp, "'%s' property specifies an unsupported memdev", VIRTIO_MEM_MEMDEV_PROP); return; + } else if (vmem->memdev->prealloc) { + error_setg(errp, "'%s' property specifies a memdev with preallocation" + " enabled: %s. Instead, specify 'prealloc=on' for the" + " virtio-mem device. ", VIRTIO_MEM_MEMDEV_PROP, + object_get_canonical_path_component(OBJECT(vmem->memdev))); + return; } if ((nb_numa_nodes && vmem->node >= nb_numa_nodes) ||