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Commit ccd46dba authored by Jike Song's avatar Jike Song Committed by Alex Williamson
Browse files

vfio: support notifier chain in vfio_group 



Beyond vfio_iommu events, users might also be interested in
vfio_group events. For example, if a vfio_group is used along
with Qemu/KVM, whenever kvm pointer is set to/cleared from the
vfio_group, users could be notified.

Currently only VFIO_GROUP_NOTIFY_SET_KVM supported.

Cc: Kirti Wankhede <kwankhede@nvidia.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: default avatarJike Song <jike.song@intel.com>
[aw: remove use of new typedef]
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 22195cbd

drivers/vfio/vfio.c

+82 −0
Original line number Diff line number Diff line
@@ -86,6 +86,8 @@ struct vfio_group { 
	struct mutex			unbound_lock;

	atomic_t			opened;

	bool				noiommu;

	struct kvm			*kvm;

	struct blocking_notifier_head	notifier;

};



struct vfio_device {
@@ -339,6 +341,7 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group) 
#ifdef CONFIG_VFIO_NOIOMMU

	group->noiommu = (iommu_group_get_iommudata(iommu_group) == &noiommu);

#endif

	BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);



	group->nb.notifier_call = vfio_iommu_group_notifier;
@@ -1581,6 +1584,9 @@ static int vfio_group_fops_release(struct inode *inode, struct file *filep) 


	filep->private_data = NULL;



	/* Any user didn't unregister? */

	WARN_ON(group->notifier.head);



	vfio_group_try_dissolve_container(group);



	atomic_dec(&group->opened);
@@ -2063,6 +2069,76 @@ static int vfio_unregister_iommu_notifier(struct vfio_group *group, 
	return ret;

}



void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm)

{

	group->kvm = kvm;

	blocking_notifier_call_chain(&group->notifier,

				VFIO_GROUP_NOTIFY_SET_KVM, kvm);

}

EXPORT_SYMBOL_GPL(vfio_group_set_kvm);



static int vfio_register_group_notifier(struct vfio_group *group,

					unsigned long *events,

					struct notifier_block *nb)

{

	struct vfio_container *container;

	int ret;

	bool set_kvm = false;



	if (*events & VFIO_GROUP_NOTIFY_SET_KVM)

		set_kvm = true;



	/* clear known events */

	*events &= ~VFIO_GROUP_NOTIFY_SET_KVM;



	/* refuse to continue if still events remaining */

	if (*events)

		return -EINVAL;



	ret = vfio_group_add_container_user(group);

	if (ret)

		return -EINVAL;



	container = group->container;

	down_read(&container->group_lock);



	ret = blocking_notifier_chain_register(&group->notifier, nb);



	/*

	 * The attaching of kvm and vfio_group might already happen, so

	 * here we replay once upon registration.

	 */

	if (!ret && set_kvm && group->kvm)

		blocking_notifier_call_chain(&group->notifier,

					VFIO_GROUP_NOTIFY_SET_KVM, group->kvm);



	up_read(&container->group_lock);

	vfio_group_try_dissolve_container(group);



	return ret;

}



static int vfio_unregister_group_notifier(struct vfio_group *group,

					 struct notifier_block *nb)

{

	struct vfio_container *container;

	int ret;



	ret = vfio_group_add_container_user(group);

	if (ret)

		return -EINVAL;



	container = group->container;

	down_read(&container->group_lock);



	ret = blocking_notifier_chain_unregister(&group->notifier, nb);



	up_read(&container->group_lock);

	vfio_group_try_dissolve_container(group);



	return ret;

}



int vfio_register_notifier(struct device *dev, enum vfio_notify_type type,

			   unsigned long *events, struct notifier_block *nb)

{
@@ -2080,6 +2156,9 @@ int vfio_register_notifier(struct device *dev, enum vfio_notify_type type, 
	case VFIO_IOMMU_NOTIFY:

		ret = vfio_register_iommu_notifier(group, events, nb);

		break;

	case VFIO_GROUP_NOTIFY:

		ret = vfio_register_group_notifier(group, events, nb);

		break;

	default:

		ret = -EINVAL;

	}
@@ -2106,6 +2185,9 @@ int vfio_unregister_notifier(struct device *dev, enum vfio_notify_type type, 
	case VFIO_IOMMU_NOTIFY:

		ret = vfio_unregister_iommu_notifier(group, nb);

		break;

	case VFIO_GROUP_NOTIFY:

		ret = vfio_unregister_group_notifier(group, nb);

		break;

	default:

		ret = -EINVAL;

	}

include/linux/vfio.h

+7 −0
Original line number Diff line number Diff line
@@ -111,11 +111,15 @@ extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, 
/* each type has independent events */

enum vfio_notify_type {

	VFIO_IOMMU_NOTIFY = 0,

	VFIO_GROUP_NOTIFY = 1,

};



/* events for VFIO_IOMMU_NOTIFY */

#define VFIO_IOMMU_NOTIFY_DMA_UNMAP	BIT(0)



/* events for VFIO_GROUP_NOTIFY */

#define VFIO_GROUP_NOTIFY_SET_KVM	BIT(0)



extern int vfio_register_notifier(struct device *dev,

				  enum vfio_notify_type type,

				  unsigned long *required_events,
@@ -124,6 +128,9 @@ extern int vfio_unregister_notifier(struct device *dev, 
				    enum vfio_notify_type type,

				    struct notifier_block *nb);



struct kvm;

extern void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm);



/*

 * Sub-module helpers

 */