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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99CF2C43334 for ; Mon, 20 Jun 2022 06:38:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238655AbiFTGiB (ORCPT ); Mon, 20 Jun 2022 02:38:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230121AbiFTGh7 (ORCPT ); Mon, 20 Jun 2022 02:37:59 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D4BDE58; Sun, 19 Jun 2022 23:37:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=dHzVAyfIa/3nUl03RRG8Cmy2hok3UdrVa+qW5Pr02mE=; b=yBNK9/iQ57Apbwe6zABDPWJp37 E8Ny/XDv27hw5gPa1YKZtipXrzgP+LPGxmCNoEaUheLXIMLuaUIlyr0NVoGs+jdbuxZiuHAu7/g6I g6mkZOqpUFGMGjvrCqFRr115ypKBrOMSJeYUbkYKWCZ3ZSCA8vqmk2lSoBnknvsWL+DS45YPJoXFV sKBq5PwAzbPjE4F/WdFJr/NHRRm8ywRkc8wS5B/Wa3xynH5FpC2L/a5erXySws2U1s7PWrAe7Dlwc /8ykwpyAdHXI3jPjJ7gNwcYk6wriBBhiRewtRqKTgvtvXQqnypmijFGaRg7KFgdAPKUxbzJ3ekfnY UHO9EwvA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1o3B2h-00GSAz-PA; Mon, 20 Jun 2022 06:37:47 +0000 Date: Sun, 19 Jun 2022 23:37:47 -0700 From: Christoph Hellwig To: Jason Gunthorpe Cc: Christoph Hellwig , Nicolin Chen , kwankhede@nvidia.com, corbet@lwn.net, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, zhenyuw@linux.intel.com, zhi.a.wang@intel.com, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, tvrtko.ursulin@linux.intel.com, airlied@linux.ie, daniel@ffwll.ch, farman@linux.ibm.com, mjrosato@linux.ibm.com, pasic@linux.ibm.com, vneethv@linux.ibm.com, oberpar@linux.ibm.com, freude@linux.ibm.com, akrowiak@linux.ibm.com, jjherne@linux.ibm.com, alex.williamson@redhat.com, cohuck@redhat.com, kevin.tian@intel.com, jchrist@linux.ibm.com, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: Re: [RFT][PATCH v1 6/6] vfio: Replace phys_pfn with phys_page for vfio_pin_pages() Message-ID: References: <20220616235212.15185-1-nicolinc@nvidia.com> <20220616235212.15185-7-nicolinc@nvidia.com> <20220620030046.GB5219@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jun 19, 2022 at 10:51:47PM -0700, Christoph Hellwig wrote: > On Mon, Jun 20, 2022 at 12:00:46AM -0300, Jason Gunthorpe wrote: > > On Fri, Jun 17, 2022 at 01:54:05AM -0700, Christoph Hellwig wrote: > > > There is a bunch of code an comments in the iommu type1 code that > > > suggest we can pin memory that is not page backed. > > > > AFAIK you can.. The whole follow_pte() mechanism allows raw PFNs to be > > loaded into the type1 maps and the pin API will happily return > > them. This happens in almost every qemu scenario because PCI MMIO BAR > > memory ends up routed down this path. > > Indeed, my read wasn't deep enough. Which means that we can't change > the ->pin_pages interface to return a struct pages array, as we don't > have one for those. Actually. gvt requires a struct page, and both s390 seem to require normal non-I/O, non-remapped kernel pointers. So I think for the vfio_pin_pages we can assume that we only want page backed memory and remove the follow_fault_pfn case entirely. But we'll probably have to keep it for the vfio_iommu_replay case that is not tied to emulated IOMMU drivers. 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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 3DD49C433EF for ; Mon, 20 Jun 2022 06:38:02 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AA66110E8B2; Mon, 20 Jun 2022 06:38:01 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by gabe.freedesktop.org (Postfix) with ESMTPS id E721A10E321; Mon, 20 Jun 2022 06:37:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=dHzVAyfIa/3nUl03RRG8Cmy2hok3UdrVa+qW5Pr02mE=; b=yBNK9/iQ57Apbwe6zABDPWJp37 E8Ny/XDv27hw5gPa1YKZtipXrzgP+LPGxmCNoEaUheLXIMLuaUIlyr0NVoGs+jdbuxZiuHAu7/g6I g6mkZOqpUFGMGjvrCqFRr115ypKBrOMSJeYUbkYKWCZ3ZSCA8vqmk2lSoBnknvsWL+DS45YPJoXFV sKBq5PwAzbPjE4F/WdFJr/NHRRm8ywRkc8wS5B/Wa3xynH5FpC2L/a5erXySws2U1s7PWrAe7Dlwc /8ykwpyAdHXI3jPjJ7gNwcYk6wriBBhiRewtRqKTgvtvXQqnypmijFGaRg7KFgdAPKUxbzJ3ekfnY UHO9EwvA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1o3B2h-00GSAz-PA; Mon, 20 Jun 2022 06:37:47 +0000 Date: Sun, 19 Jun 2022 23:37:47 -0700 From: Christoph Hellwig To: Jason Gunthorpe Message-ID: References: <20220616235212.15185-1-nicolinc@nvidia.com> <20220616235212.15185-7-nicolinc@nvidia.com> <20220620030046.GB5219@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Subject: Re: [Intel-gfx] [RFT][PATCH v1 6/6] vfio: Replace phys_pfn with phys_page for vfio_pin_pages() X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mjrosato@linux.ibm.com, linux-doc@vger.kernel.org, airlied@linux.ie, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kwankhede@nvidia.com, vneethv@linux.ibm.com, agordeev@linux.ibm.com, pasic@linux.ibm.com, kvm@vger.kernel.org, corbet@lwn.net, Christoph Hellwig , Nicolin Chen , borntraeger@linux.ibm.com, intel-gfx@lists.freedesktop.org, jjherne@linux.ibm.com, farman@linux.ibm.com, jchrist@linux.ibm.com, gor@linux.ibm.com, linux-s390@vger.kernel.org, hca@linux.ibm.com, freude@linux.ibm.com, rodrigo.vivi@intel.com, intel-gvt-dev@lists.freedesktop.org, akrowiak@linux.ibm.com, cohuck@redhat.com, oberpar@linux.ibm.com, svens@linux.ibm.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Sun, Jun 19, 2022 at 10:51:47PM -0700, Christoph Hellwig wrote: > On Mon, Jun 20, 2022 at 12:00:46AM -0300, Jason Gunthorpe wrote: > > On Fri, Jun 17, 2022 at 01:54:05AM -0700, Christoph Hellwig wrote: > > > There is a bunch of code an comments in the iommu type1 code that > > > suggest we can pin memory that is not page backed. > > > > AFAIK you can.. The whole follow_pte() mechanism allows raw PFNs to be > > loaded into the type1 maps and the pin API will happily return > > them. This happens in almost every qemu scenario because PCI MMIO BAR > > memory ends up routed down this path. > > Indeed, my read wasn't deep enough. Which means that we can't change > the ->pin_pages interface to return a struct pages array, as we don't > have one for those. Actually. gvt requires a struct page, and both s390 seem to require normal non-I/O, non-remapped kernel pointers. So I think for the vfio_pin_pages we can assume that we only want page backed memory and remove the follow_fault_pfn case entirely. But we'll probably have to keep it for the vfio_iommu_replay case that is not tied to emulated IOMMU drivers.