From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755862AbcETJXq (ORCPT ); Fri, 20 May 2016 05:23:46 -0400 Received: from mail-wm0-f52.google.com ([74.125.82.52]:36089 "EHLO mail-wm0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755834AbcETJXn (ORCPT ); Fri, 20 May 2016 05:23:43 -0400 Subject: Re: [PATCH] vfio: platform: use vfio_iommu_group_get/put To: Peng Fan , Baptiste Reynal References: <1462788103-19906-1-git-send-email-van.freenix@gmail.com> <20160509093238.3901f0b7@t450s.home> <20160510074025.GA1064@linux-7smt.suse> <20160519150149.7a8b80ba@ul30vt.home> <573EC3A8.4050008@linaro.org> <20160520083627.GA23014@linux-7smt.suse> Cc: Alex Williamson , "open list:VFIO DRIVER" , open list From: Eric Auger Message-ID: <573ED745.1040900@linaro.org> Date: Fri, 20 May 2016 11:22:13 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <20160520083627.GA23014@linux-7smt.suse> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peng, On 05/20/2016 10:36 AM, Peng Fan wrote: > Hi, > > On Fri, May 20, 2016 at 10:20:32AM +0200, Baptiste Reynal wrote: >> Hi, >> >> On Fri, May 20, 2016 at 9:58 AM, Eric Auger wrote: >>> >>> Hi, >>> On 05/19/2016 11:01 PM, Alex Williamson wrote: >>>> On Tue, 10 May 2016 15:40:28 +0800 >>>> Peng Fan wrote: >>>> >>>>> Hi Alex, >>>>> >>>>> On Mon, May 09, 2016 at 09:32:38AM -0600, Alex Williamson wrote: >>>>>> On Mon, 9 May 2016 18:01:43 +0800 >>>>>> Peng Fan wrote: >>>>>> >>>>>>> Use vfio_iommu_group_get and vfio_iommu_group_put, but not >>>>>>> iommu_group_get or iommu_group_put. >>>>>> >>>>>> I assume you're trying to duplicate the vfio_pci changes from commit >>>>>> 03a76b60f8ba to enable no-iommu mode. That would be really relevant >>>>>> information for the commit log. >>>>> >>>>> This is not to support non-iommu for vfio platform. I just think >>>>> vfio_iommu_group_get/put is vfio core API and should be used by >>>>> vfio-pci and vfio-platform. >>>> >>>> Hi Peng, >>>> >>>> I suppose I would consider this an optional part of the internal vfio >>>> API, it's only real purpose it to provide the ability to create fake >>>> groups which are only used for no-iommu. It's perfectly legitimate to >>>> use iommu_group_get/put if there is no desire to enable no-iommu. >>>> Baptiste, Eric, do you have an opinion whether enabling no-iommu in >>>> vfio/platform is something we should do? Thanks, >>> I think it would make sense to introduce that no-iommu feature for >>> vfio-platform because it allows potential users to get familiar with >>> VFIO platform without having the proper HW. I also thought the primary >>> purpose of this patch was to introduce that support. > > Yeah. Initially I would like to try vfio on my i.MX6/7 boards which does not > have HW iommu. I am new to this, so just wrote this simple patch when I was > reading the source code. > >> >> Since safety issues have already been addressed for the PCI patch >> series, I don't see any reason not to enable it. You might extend the >> commit message to remind those issues. > > Eric, Baptiste, > > Is vfio-platform no-iommu on your TODO list? I am happy to help test. > If not, I can try work on this if you could guide me -:) No it is not at the moment. shouldn't it work already with this very patch? I will be happy to bring support to you if needed. Best Regards Eric > > Thanks, > Peng. >> >> Best regards, >> Baptiste >> >>> >>> Best Regards >>> >>> Eric >>>> >>>> Alex >>>> >>>>>>> >>>>>>> Signed-off-by: Peng Fan >>>>>>> Cc: Baptiste Reynal >>>>>>> Cc: Alex Williamson >>>>>>> --- >>>>>>> drivers/vfio/platform/vfio_platform_common.c | 6 +++--- >>>>>>> 1 file changed, 3 insertions(+), 3 deletions(-) >>>>>>> >>>>>>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c >>>>>>> index e65b142..582885e 100644 >>>>>>> --- a/drivers/vfio/platform/vfio_platform_common.c >>>>>>> +++ b/drivers/vfio/platform/vfio_platform_common.c >>>>>>> @@ -561,7 +561,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, >>>>>>> >>>>>>> vdev->device = dev; >>>>>>> >>>>>>> - group = iommu_group_get(dev); >>>>>>> + group = vfio_iommu_group_get(dev); >>>>>>> if (!group) { >>>>>>> pr_err("VFIO: No IOMMU group for device %s\n", vdev->name); >>>>>>> return -EINVAL; >>>>>>> @@ -569,7 +569,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, >>>>>>> >>>>>>> ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev); >>>>>>> if (ret) { >>>>>>> - iommu_group_put(group); >>>>>>> + vfio_iommu_group_put(group); >>>>>>> return ret; >>>>>>> } >>>>>>> >>>>>>> @@ -589,7 +589,7 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev) >>>>>>> >>>>>>> if (vdev) { >>>>>>> vfio_platform_put_reset(vdev); >>>>>>> - iommu_group_put(dev->iommu_group); >>>>>>> + vfio_iommu_group_put(dev->iommu_group, dev); >>>>>>> } >>>>>>> >>>>>>> return vdev; >>>>>> >>>> >>>