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 C0435C11F69 for ; Wed, 30 Jun 2021 06:49:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A427F61A1D for ; Wed, 30 Jun 2021 06:49:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232520AbhF3GwQ (ORCPT ); Wed, 30 Jun 2021 02:52:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232018AbhF3GwO (ORCPT ); Wed, 30 Jun 2021 02:52:14 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF4BCC061766; Tue, 29 Jun 2021 23:49:45 -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=b+svzs78j/62UsetKE/X8fy/L/Rti/5BS8qNFSo3AdY=; b=YvWJ06tpNI/PQXlniltz4HwA3w qvb35mtIRc7zoasrxSW0mwsdp8zrl4IJSUR7/UExaPp/G8HsbZqhmZlr4ASbIIp59RN4JH3VQh7fp xHEDUrkCCy2uCHpgfbSjVyKOkg4PTOCvVF4Enjph0VlxcF4zTLWkTlRaISyXvZB/VwmOM3y+FpBoV 6qZoJl6WMlxndz8lCibcQIqcC5UECay58H2CbwSkj9LoPW1VLcWhEzsZrRfGx/73bje+xZPfyhKNH lVnlsQnRDYwDqRdQZanFGZ7dwRrA4fkXGgnVrpwNPbUCu1xejZSK9SK+jWBqCRn8QlyeNiYye6v4P Swb3eHsA==; Received: from hch by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1lyU1x-0050Oj-1M; Wed, 30 Jun 2021 06:49:09 +0000 Date: Wed, 30 Jun 2021 07:49:05 +0100 From: Christoph Hellwig To: Jason Gunthorpe Cc: Alex Williamson , Jean-Philippe Brucker , "Tian, Kevin" , "Jiang, Dave" , "Raj, Ashok" , "kvm@vger.kernel.org" , Jonathan Corbet , David Woodhouse , Jason Wang , LKML , Kirti Wankhede , "iommu@lists.linux-foundation.org" , Paolo Bonzini , Robin Murphy , David Gibson Subject: Re: [RFC] /dev/ioasid uAPI proposal Message-ID: References: <30e5c597-b31c-56de-c75e-950c91947d8f@redhat.com> <20210604160336.GA414156@nvidia.com> <2c62b5c7-582a-c710-0436-4ac5e8fd8b39@redhat.com> <20210604172207.GT1002214@nvidia.com> <20210604152918.57d0d369.alex.williamson@redhat.com> <20210604230108.GB1002214@nvidia.com> <20210607094148.7e2341fc.alex.williamson@redhat.com> <20210607181858.GM1002214@nvidia.com> <20210607125946.056aafa2.alex.williamson@redhat.com> <20210607190802.GO1002214@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210607190802.GO1002214@nvidia.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-kernel@vger.kernel.org On Mon, Jun 07, 2021 at 04:08:02PM -0300, Jason Gunthorpe wrote: > Compatibility is important, but when I look in the kernel code I see > very few places that call wbinvd(). Basically all DRM for something > relavent to qemu. > > That tells me that the vast majority of PCI devices do not generate > no-snoop traffic. Part of it is that we have no general API for it, because the DRM folks as usual just tarted piling up local hacks instead of introducing a proper API..