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=-11.0 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,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 063E1C43381 for ; Thu, 7 Jan 2021 10:37:55 +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 445D92313B for ; Thu, 7 Jan 2021 10:37:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 445D92313B 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]:54626 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kxSfx-0001ol-6s for qemu-devel@archiver.kernel.org; Thu, 07 Jan 2021 05:37:53 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:44264) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kxSek-0001NO-Ed for qemu-devel@nongnu.org; Thu, 07 Jan 2021 05:36:38 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:31143) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kxSei-0004Xx-55 for qemu-devel@nongnu.org; Thu, 07 Jan 2021 05:36:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610015794; 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: in-reply-to:in-reply-to:references:references; bh=qktnC06QgromIDzebo/9LwPb+YTd7N7wq0sBVkjGF3w=; b=AinifsZ7X9luCCN4kW4Tl8GWJPy99h+gJ5Vyg7ipvSlQuOTJCTZKzurdpWR5gkvm9l+uR0 GauGmM15067zWsnYqx4dNfuhedELn8fPW7kQLdIWeBAsDXof/4Y+VP2QvaYm3UqBlzDkTr V6NIKhFICttD3Hw1EW2240h+vI6b4Tg= 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-480-9ulOn1gJO1CyHmJ28GiAbw-1; Thu, 07 Jan 2021 05:36:32 -0500 X-MC-Unique: 9ulOn1gJO1CyHmJ28GiAbw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6A3548144E3; Thu, 7 Jan 2021 10:36:31 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-114-197.ams2.redhat.com [10.36.114.197]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 435C677BE1; Thu, 7 Jan 2021 10:36:26 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 79D501800620; Thu, 7 Jan 2021 11:36:24 +0100 (CET) Date: Thu, 7 Jan 2021 11:36:24 +0100 From: Gerd Hoffmann To: Laurent Vivier Subject: Re: [PATCH] virtio-mmio: fix guest kernel crash with SHM regions Message-ID: <20210107103624.v67snigf33lpynai@sirius.home.kraxel.org> References: <20201220163539.2255963-1-laurent@vivier.eu> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kraxel@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=63.128.21.124; envelope-from=kraxel@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.252, 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_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: qemu-devel@nongnu.org, "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi, > > According to the comments in the kernel, a non existent shared region > > has a length of (u64)-1. virtio spec says the same. > > + case VIRTIO_MMIO_SHM_LEN_LOW: > > + case VIRTIO_MMIO_SHM_LEN_HIGH: > > + /* > > + * VIRTIO_MMIO_SHM_SEL is unimplemented > > + * according to the linux driver, if region length is -1 > > + * the shared memory doesn't exist > > + */ > > + return -1; Acked-by: Gerd Hoffmann take care, Gerd