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vfio: support notifier chain in vfio_group

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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: Jike Song <jike.song@intel.com>
[aw: remove use of new typedef]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Jike Song 2016-12-01 13:20:06 +08:00 committed by Alex Williamson
parent 22195cbd34
commit ccd46dbae7
2 changed files with 89 additions and 0 deletions
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82
drivers/vfio/vfio.c
View file

@ -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;
}

7
include/linux/vfio.h
View file

@ -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
*/