On Thu, 17 Nov 2016 20:57:10 +0800
Jike Song <jike.song@xxxxxxxxx> 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 | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/vfio.h | 6 ++++++
> 2 files changed, 63 insertions(+)
>
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index 819c7f9..85a14ee 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 {
> @@ -312,6 +314,10 @@ static void vfio_group_unlock_and_free(struct vfio_group *group)
> * that the group is no longer in vfio.group_list.
> */
> iommu_group_unregister_notifier(group->iommu_group, &group->nb);
> +
> + /* Any user didn't unregister? */
> + WARN_ON(group->notifier.head);
> +
Should be in vfio_group_fops_release() per the other thread.
> kfree(group);
> }
>
> @@ -339,6 +345,7 @@ 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;
>
> @@ -1015,6 +1022,50 @@ static long vfio_ioctl_check_extension(struct vfio_container *container,
> 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)
> +{
> + int ret;
> + bool replay = false;
'bool set_kvm' maybe
> +
> + /* clear known events */
> + if (*events & VFIO_GROUP_NOTIFY_SET_KVM) {
> + replay = true;
> + *events &= ~VFIO_GROUP_NOTIFY_SET_KVM;
> + }
> +
> + /* refuse to continue if still events remaining */
> + if (*events)
> + return -EINVAL;
> +
> + 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 && replay && group->kvm)
> + blocking_notifier_call_chain(&group->notifier,
> + VFIO_GROUP_NOTIFY_SET_KVM, group->kvm);
> +
> + return ret;
> +}
> +
> +static int vfio_unregister_group_notifier(struct vfio_group *group,
> + struct notifier_block *nb)
> +{
> + return blocking_notifier_chain_unregister(&group->notifier, nb);
> +}
> +
> /* hold write lock on container->group_lock */
> static int __vfio_container_attach_groups(struct vfio_container *container,
> struct vfio_iommu_driver *driver,
> @@ -2089,6 +2140,9 @@ 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);
When we set a notifier on an iommu_group we add a container user which
goes through validating whether the container is in the correct state.
We're doing none of that for groups. Do we really want the vendor
driver to be able to set a notifier for an unused group?
vfio_register_group_notifier() should probably be checking
group->opened.
> + break;
> default:
> ret = EINVAL;
> }
> @@ -2115,6 +2169,9 @@ 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);
>
> /*
> * Sub-module helpers
--
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