From ccd46dbae77dbf0d33f42e04b59536f108c395e8 Mon Sep 17 00:00:00 2001 From: Jike Song Date: Thu, 1 Dec 2016 13:20:06 +0800 Subject: 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 Cc: Paolo Bonzini Cc: Xiao Guangrong Signed-off-by: Jike Song [aw: remove use of new typedef] Signed-off-by: Alex Williamson --- drivers/vfio/vfio.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) (limited to 'drivers/vfio') diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 6cc2a9ffac10..9901c4671e2f 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -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; } -- cgit