On 11/22/2016 11:39 AM, Jike Song wrote:
> 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: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Cc: Kirti Wankhede <kwankhede@xxxxxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> Signed-off-by: Jike Song <jike.song@xxxxxxxxx>
> ---
> drivers/vfio/vfio.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/vfio.h | 6 ++++
> 2 files changed, 88 insertions(+)
>
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index 493bbad..3ab5edb 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);
> @@ -2069,6 +2075,76 @@ 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, vfio_notify_type_t type,
> unsigned long *events,
> struct notifier_block *nb)
> @@ -2087,6 +2163,9 @@ int vfio_register_notifier(struct device *dev, vfio_notify_type_t 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;
> }
> @@ -2113,6 +2192,9 @@ int vfio_unregister_notifier(struct device *dev, vfio_notify_type_t 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;
> }
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 6f3ff31..5d46e3c 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -119,11 +119,17 @@ extern int vfio_unregister_notifier(struct device *dev,
> /* each type has independent events */
> enum vfio_notify_type {
> VFIO_IOMMU_NOTIFY = (__force vfio_notify_type_t)0,
> + VFIO_GROUP_NOTIFY = (__force vfio_notify_type_t)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)
> +
> +struct kvm;
> +extern void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm);
>
If I understand correctly, notifier for backend iommu driver and
notifier for group should be registered with different notifier blocks,
as per your current implementation:
unsigned long iommu_event = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
struct notifier_block iommu_nb;
iommu_nb.notifier_call = vfio_iommu_notifier_cb;
vfio_register_notifier(dev, VFIO_IOMMU_NOTIFY, &iommu_event, &iommu_nb);
unsigned long group_event = VFIO_GROUP_NOTIFY_SET_KVM;
struct notifier_block group_nb;
group_nb.notifier_call = vfio_group_notifier_cb;
vfio_register_notifier(dev, VFIO_GROUP_NOTIFY, &group_event, &group_nb);
Then what is the use of having 'events' bitmask as input argument?
Its clear that caller should set:
- VFIO_IOMMU_NOTIFY_DMA_UNMAP when vfio_notify_type_t is VFIO_IOMMU_NOTIFY
- VFIO_GROUP_NOTIFY_SET_KVM when vfio_notify_type_t is VFIO_GROUP_NOTIFY
Notifier action could be a integer as earlier and indexing of action
would be different for both notifiers.
Then caller don't have to sent event bitmask, for caller it would look like:
struct notifier_block iommu_nb;
iommu_nb.notifier_call = vfio_iommu_notifier_cb;
vfio_register_notifier(dev, VFIO_IOMMU_NOTIFY, &iommu_nb);
struct notifier_block group_nb;
group_nb.notifier_call = vfio_group_notifier_cb;
vfio_register_notifier(dev, VFIO_GROUP_NOTIFY, &group_nb);
Thanks,
Kirti
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