Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756823AbaKTOLO (ORCPT ); Thu, 20 Nov 2014 09:11:14 -0500 Received: from mail-pd0-f169.google.com ([209.85.192.169]:40691 "EHLO mail-pd0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756700AbaKTOLL (ORCPT ); Thu, 20 Nov 2014 09:11:11 -0500 MIME-Version: 1.0 X-Originating-IP: [2a01:e35:2434:4600:224:8cff:fe66:7f7e] In-Reply-To: <1415810168.16601.353.camel@ul30vt.home> References: <1414433284-31719-1-git-send-email-a.motakis@virtualopensystems.com> <1414433284-31719-7-git-send-email-a.motakis@virtualopensystems.com> <5463373C.2010202@linaro.org> <1415810168.16601.353.camel@ul30vt.home> From: Antonios Motakis Date: Thu, 20 Nov 2014 15:10:50 +0100 Message-ID: Subject: Re: [PATCH v9 06/19] vfio/platform: return info for bound device To: Alex Williamson Cc: Eric Auger , kvm-arm , Linux IOMMU , Will Deacon , VirtualOpenSystems Technical Team , Christoffer Dall , Kim Phillips , Marc Zyngier , VFIO DRIVER , open list Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 12, 2014 at 5:36 PM, Alex Williamson wrote: > On Wed, 2014-11-12 at 11:32 +0100, Eric Auger wrote: >> On 10/27/2014 07:07 PM, Antonios Motakis wrote: >> > A VFIO userspace driver will start by opening the VFIO device >> > that corresponds to an IOMMU group, and will use the ioctl interface >> > to get the basic device info, such as number of memory regions and >> > interrupts, and their properties. This patch enables the >> > VFIO_DEVICE_GET_INFO ioctl call. >> > >> > Signed-off-by: Antonios Motakis >> > --- >> > drivers/vfio/platform/vfio_platform_common.c | 23 ++++++++++++++++++++--- >> > 1 file changed, 20 insertions(+), 3 deletions(-) >> > >> > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c >> > index e0fdbc8..cb20526 100644 >> > --- a/drivers/vfio/platform/vfio_platform_common.c >> > +++ b/drivers/vfio/platform/vfio_platform_common.c >> > @@ -43,10 +43,27 @@ static int vfio_platform_open(void *device_data) >> > static long vfio_platform_ioctl(void *device_data, >> > unsigned int cmd, unsigned long arg) >> > { >> > - if (cmd == VFIO_DEVICE_GET_INFO) >> > - return -EINVAL; >> > + struct vfio_platform_device *vdev = device_data; >> > + unsigned long minsz; >> > + >> > + if (cmd == VFIO_DEVICE_GET_INFO) { >> > + struct vfio_device_info info; >> > + >> > + minsz = offsetofend(struct vfio_device_info, num_irqs); >> > + >> > + if (copy_from_user(&info, (void __user *)arg, minsz)) >> > + return -EFAULT; >> > + >> > + if (info.argsz < minsz) >> > + return -EINVAL; >> > + >> > + info.flags = vdev->flags; >> > + info.num_regions = 0; >> > + info.num_irqs = 0; >> Seems a bit weird to me to enable the modality but returning zeroed >> values. Shouldn't we put that patch after VFIO_DEVICE_GET_REGION_INFO >> and VFIO_DEVICE_GET_IRQ_INFO ones? > > I actually like how Antonios has started from a base framework, exposing > a device but none of the resources and then incrementally adds each > component. It's also a good showcase of the VFIO ABI that we can do > things like this. Thanks, I also agree with Alex with this. But of course I'm not married with any particular splitting style, in case we decide to change this. > > Alex > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/