From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37110) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1asEM6-0002Wu-UH for qemu-devel@nongnu.org; Mon, 18 Apr 2016 14:57:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1asEM1-0000qP-RD for qemu-devel@nongnu.org; Mon, 18 Apr 2016 14:57:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53303) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1asEM1-0000ns-Ju for qemu-devel@nongnu.org; Mon, 18 Apr 2016 14:57:01 -0400 Date: Mon, 18 Apr 2016 12:56:58 -0600 From: Alex Williamson Message-ID: <20160418125658.48ffd105@t450s.home> In-Reply-To: <1460973374-32719-3-git-send-email-mst@redhat.com> References: <1460973374-32719-1-git-send-email-mst@redhat.com> <1460973374-32719-3-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH RFC 2/3] vfio: report group noiommu status List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, Jason Wang , Andy Lutomirski , Christian Borntraeger , Cornelia Huck , Wei Liu , David Woodhouse , virtualization@lists.linux-foundation.org, qemu-devel@nongnu.org, kvm@vger.kernel.org, Jonathan Corbet , Baptiste Reynal , Julia Lawall , Dan Carpenter , linux-doc@vger.kernel.org On Mon, 18 Apr 2016 12:58:20 +0300 "Michael S. Tsirkin" wrote: > When using vfio, callers might want to know whether device is added to a > regular group or an non-iommu group. > > Report this status from vfio_add_group_dev. > > Signed-off-by: Michael S. Tsirkin > --- What about making an interface to query this rather than playing games with magic return values? bool vfio_iommu_group_is_noiommu(struct iommu_group *group) { return iommu_group_get_iommudata(group) == &noiommu; } > drivers/vfio/pci/vfio_pci.c | 2 +- > drivers/vfio/platform/vfio_platform_common.c | 2 +- > drivers/vfio/vfio.c | 5 ++++- > Documentation/vfio.txt | 4 +++- > 4 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c > index 712a849..d622a41 100644 > --- a/drivers/vfio/pci/vfio_pci.c > +++ b/drivers/vfio/pci/vfio_pci.c > @@ -1119,7 +1119,7 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > spin_lock_init(&vdev->irqlock); > > ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev); > - if (ret) { > + if (ret < 0) { > vfio_iommu_group_put(group, &pdev->dev); > kfree(vdev); > return ret; > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c > index e65b142..bf74e21 100644 > --- a/drivers/vfio/platform/vfio_platform_common.c > +++ b/drivers/vfio/platform/vfio_platform_common.c > @@ -568,7 +568,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev, > } > > ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev); > - if (ret) { > + if (ret < 0) { > iommu_group_put(group); > return ret; > } > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index 6fd6fa5..67db231 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -756,6 +756,7 @@ int vfio_add_group_dev(struct device *dev, > struct iommu_group *iommu_group; > struct vfio_group *group; > struct vfio_device *device; > + int noiommu; > > iommu_group = iommu_group_get(dev); > if (!iommu_group) > @@ -791,6 +792,8 @@ int vfio_add_group_dev(struct device *dev, > return PTR_ERR(device); > } > > + noiommu = group->noiommu; > + > /* > * Drop all but the vfio_device reference. The vfio_device holds > * a reference to the vfio_group, which holds a reference to the > @@ -798,7 +801,7 @@ int vfio_add_group_dev(struct device *dev, > */ > vfio_group_put(group); > > - return 0; > + return noiommu; > } > EXPORT_SYMBOL_GPL(vfio_add_group_dev); > > diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt > index 1dd3fdd..d76be0f 100644 > --- a/Documentation/vfio.txt > +++ b/Documentation/vfio.txt > @@ -259,7 +259,9 @@ extern void *vfio_del_group_dev(struct device *dev); > > vfio_add_group_dev() indicates to the core to begin tracking the > specified iommu_group and register the specified dev as owned by > -a VFIO bus driver. The driver provides an ops structure for callbacks > +a VFIO bus driver. A negative return value indicates failure. > +A positive return value indicates that an unsafe noiommu mode > +is in use. The driver provides an ops structure for callbacks > similar to a file operations structure: > > struct vfio_device_ops {