From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43706) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c6XYn-00052M-DN for qemu-devel@nongnu.org; Tue, 15 Nov 2016 01:49:38 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c6XYk-0002EV-9p for qemu-devel@nongnu.org; Tue, 15 Nov 2016 01:49:37 -0500 Received: from mga06.intel.com ([134.134.136.31]:30942) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c6XYk-0002E5-1s for qemu-devel@nongnu.org; Tue, 15 Nov 2016 01:49:34 -0500 Message-ID: <582AAF16.5080906@intel.com> Date: Tue, 15 Nov 2016 14:45:42 +0800 From: Jike Song MIME-Version: 1.0 References: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com> <1479138156-28905-13-git-send-email-kwankhede@nvidia.com> In-Reply-To: <1479138156-28905-13-git-send-email-kwankhede@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v12 12/22] vfio: Add notifier callback to parent's ops structure of mdev List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kirti Wankhede Cc: alex.williamson@redhat.com, pbonzini@redhat.com, kraxel@redhat.com, cjia@nvidia.com, qemu-devel@nongnu.org, kvm@vger.kernel.org, kevin.tian@intel.com, bjsdjshi@linux.vnet.ibm.com, linux-kernel@vger.kernel.org On 11/14/2016 11:42 PM, Kirti Wankhede wrote: > Add a notifier calback to parent's ops structure of mdev device so that per > device notifer for vfio module is registered through vfio_mdev module. > > Signed-off-by: Kirti Wankhede > Signed-off-by: Neo Jia > Change-Id: Iafa6f1721aecdd6e50eb93b153b5621e6d29b637 > --- > drivers/vfio/mdev/vfio_mdev.c | 19 +++++++++++++++++++ > include/linux/mdev.h | 9 +++++++++ > 2 files changed, 28 insertions(+) > > diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c > index ffc36758cb84..1694b1635607 100644 > --- a/drivers/vfio/mdev/vfio_mdev.c > +++ b/drivers/vfio/mdev/vfio_mdev.c > @@ -24,6 +24,15 @@ > #define DRIVER_AUTHOR "NVIDIA Corporation" > #define DRIVER_DESC "VFIO based driver for Mediated device" > > +static int vfio_mdev_notifier(struct notifier_block *nb, unsigned long action, > + void *data) > +{ > + struct mdev_device *mdev = container_of(nb, struct mdev_device, nb); > + struct parent_device *parent = mdev->parent; > + > + return parent->ops->notifier(mdev, action, data); > +} > + > static int vfio_mdev_open(void *device_data) > { > struct mdev_device *mdev = device_data; > @@ -40,6 +49,11 @@ static int vfio_mdev_open(void *device_data) > if (ret) > module_put(THIS_MODULE); > > + if (likely(parent->ops->notifier)) { > + mdev->nb.notifier_call = vfio_mdev_notifier; > + if (vfio_register_notifier(&mdev->dev, &mdev->nb)) > + pr_err("Failed to register notifier for mdev\n"); > + } Hi Kirti, Could you please move the notifier registration before parent->ops->open()? as you might know, I'm extending your vfio_register_notifier to also include the attaching/detaching events of vfio_group and kvm. Basically if vfio_group not attached to any kvm instance, the parent->ops->open() should return -ENODEV to indicate the failure, but to know whether kvm is available in open(), the notifier registration should be earlier. Of course I can call vfio_register_notifier() from an earlier place to workaround it, but it doesn't seem a canonical way. -- Thanks, Jike > return ret; > } > > @@ -48,6 +62,11 @@ static void vfio_mdev_release(void *device_data) > struct mdev_device *mdev = device_data; > struct parent_device *parent = mdev->parent; > > + if (likely(parent->ops->notifier)) { > + if (vfio_unregister_notifier(&mdev->dev, &mdev->nb)) > + pr_err("Failed to unregister notifier for mdev\n"); > + } > + > if (likely(parent->ops->release)) > parent->ops->release(mdev); > > diff --git a/include/linux/mdev.h b/include/linux/mdev.h > index 4900cc472364..665afe0a4c31 100644 > --- a/include/linux/mdev.h > +++ b/include/linux/mdev.h > @@ -37,6 +37,7 @@ struct mdev_device { > struct kref ref; > struct list_head next; > struct kobject *type_kobj; > + struct notifier_block nb; > }; > > /** > @@ -85,6 +86,12 @@ struct mdev_device { > * @mmap: mmap callback > * @mdev: mediated device structure > * @vma: vma structure > + * @notifer: Notifier callback, currently only for > + * VFIO_IOMMU_NOTIFY_DMA_UNMAP action notified duing > + * DMA_UNMAP call on mapped iova range. > + * @mdev: mediated device structure > + * @action: Action for which notifier is called > + * @data: Data associated with the notifier > * Parent device that support mediated device should be registered with mdev > * module with parent_ops structure. > **/ > @@ -106,6 +113,8 @@ struct parent_ops { > ssize_t (*ioctl)(struct mdev_device *mdev, unsigned int cmd, > unsigned long arg); > int (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma); > + int (*notifier)(struct mdev_device *mdev, unsigned long action, > + void *data); > }; > > /* interface for exporting mdev supported type attributes */ >