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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 6A6EDC433C1 for ; Mon, 22 Mar 2021 19:50:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D90C61934 for ; Mon, 22 Mar 2021 19:50:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230027AbhCVTth (ORCPT ); Mon, 22 Mar 2021 15:49:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229771AbhCVTtB (ORCPT ); Mon, 22 Mar 2021 15:49:01 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF890C061574 for ; Mon, 22 Mar 2021 12:49:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=a2YNmkFHFWJdUV3G4mTov/7QvS9+ADavhMLaJEkKeio=; b=i9FF28K/oSTYnMuAINyz46NpQC Z+smB3s551EiSa/A9n+LWS58Afh9EvXd7Pitjf62vJyPjACu07shyPBI0Cexhgkuez31YesBTq8H3 VcoOwfEUf0wSnT/OBP24DwjWYSDW3aAqcImD3giQ3aL77ZdQkWAZ1V5WOn0bFJoLl82r5b+YMR6K6 833z2n91XflFRYWQ4dUFTxIVdScJFp9CUMt+0fDmzIvdygDxAzaDN2bMfl88eW9vSw4113veLxh4f sJlQfpsk2Xxz8XPf7y6Nv+D7ZGRKs7DwTRLPNk9fd1BGf0unE4Gu5kuIWIKqL/5eYpWQuT1d6KTVo mufPP4Sg==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lOQX5-008zTM-3z; Mon, 22 Mar 2021 19:48:18 +0000 Date: Mon, 22 Mar 2021 19:48:11 +0000 From: Christoph Hellwig To: Lorenzo Pieralisi Cc: Jon Derrick , linux-pci@vger.kernel.org, Bjorn Helgaas , Nirmal Patel , Sushma Kalakota Subject: Re: [PATCH 0/5] Legacy direct-assign mode Message-ID: <20210322194811.GA2141770@infradead.org> References: <20201120225144.15138-1-jonathan.derrick@intel.com> <20210322122837.GC11469@e121166-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210322122837.GC11469@e121166-lin.cambridge.arm.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Mar 22, 2021 at 12:28:37PM +0000, Lorenzo Pieralisi wrote: > > correctly program bridge windows with physical addresses. Some customers are > > using a legacy method that relies on the VMD subdevice domain's root port > > windows to be written with the physical addresses. This method also allows > > other hypervisors besides QEMU/KVM to perform guest passthrough. This seems like a bad idea. What are these other hypervisors? AFAIK there are no purely userspace hypervisors, so in other words what you propose here is only for unsupported external modules. I don't think we shoud merge something like this.