A vfio_group may be or may not be attached to a KVM instance,
if it is, the user of vfio_group might also want to know which
KVM instance it is attached to, and when it will detach. In VFIO
there are already external APIs for KVM to get/put vfio_group,
by providing a similar vfio_group_notify, KVM can notify the
vfio_group about attaching events.
Cc: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
Signed-off-by: Jike Song <jike.song@xxxxxxxxx>
---
drivers/vfio/vfio.c | 30 ++++++++++++++++++++++++++++++
include/linux/vfio.h | 4 ++++
2 files changed, 34 insertions(+)
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 0afb58e..b149ced 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 {
@@ -1015,6 +1017,34 @@ static long vfio_ioctl_check_extension(struct vfio_container *container,
return ret;
}
+void vfio_group_notify(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_notify);
+
+static void vfio_group_register_notifier(struct vfio_group *group,
+ struct notifier_block *nb)
+{
+ blocking_notifier_chain_register(&group->notifier, nb);
+
+ /*
+ * The attaching of kvm and vfio_group might already happen, so
+ * here we replay once on registration.
+ */
+ if (group->kvm)
+ blocking_notifier_call_chain(&group->notifier,
+ VFIO_GROUP_NOTIFY_SET_KVM, group->kvm);
+}
+
+static void vfio_group_unregister_notifier(struct vfio_group *group,
+ struct notifier_block *nb)
+{
+ 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,
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index d4ce14d..ec9f74f 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -100,6 +100,9 @@ extern void vfio_unregister_iommu_driver(
extern long vfio_external_check_extension(struct vfio_group *group,
unsigned long arg);
+struct kvm;
+extern void vfio_group_notify(struct vfio_group *group, struct kvm *kvm);
+
/*
* Sub-module helpers
*/
@@ -149,6 +152,7 @@ extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,
int npage);
#define VFIO_IOMMU_NOTIFY_DMA_UNMAP 1
+#define VFIO_GROUP_NOTIFY_SET_KVM 2
extern int vfio_register_notifier(struct device *dev,
struct notifier_block *nb);
--
1.9.1
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