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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E0281C04AB6 for ; Fri, 31 May 2019 14:39:19 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B8E7326ABC for ; Fri, 31 May 2019 14:39:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B8E7326ABC 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 ([127.0.0.1]:44609 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWigg-0004ZF-Ic for qemu-devel@archiver.kernel.org; Fri, 31 May 2019 10:39:18 -0400 Received: from eggs.gnu.org ([209.51.188.92]:47219) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWifQ-0003xW-SK for qemu-devel@nongnu.org; Fri, 31 May 2019 10:38:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hWifO-0001r8-WC for qemu-devel@nongnu.org; Fri, 31 May 2019 10:38:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57740) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hWifN-00014j-Vc for qemu-devel@nongnu.org; Fri, 31 May 2019 10:37:58 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B60DF317916F; Fri, 31 May 2019 14:37:36 +0000 (UTC) Received: from x1.home (ovpn-116-22.phx2.redhat.com [10.3.116.22]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0C9ED2FC51; Fri, 31 May 2019 14:37:34 +0000 (UTC) Date: Fri, 31 May 2019 08:37:32 -0600 From: Alex Williamson To: Thanos Makatos Message-ID: <20190531083732.37ecbb1e@x1.home> In-Reply-To: References: Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Fri, 31 May 2019 14:37:41 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] QEMU tries to register to VFIO memory that is not RAM X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "qemu-devel@nongnu.org" , Swapnil Ingle , Felipe Franciosi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 31 May 2019 13:32:29 +0000 Thanos Makatos wrote: > When configuring device pass-through via VFIO to a VM, I noticed that > QEMU tries to register (DMA_MAP) all memory regions of a guest (not > only RAM). That includes firmware regions like "pc.rom". Would a > physical device ever need access to those? Probably not, but are those things not in the address space of the device on a physical system? > Am I missing something? Does this cause a problem? It's not always easy to identify regions that should not be mapped to a device, clearly we're not going to create a whitelist based on the name of the region. Thanks, Alex