Instead of having drivers register the notifier with explicit code just
have them provide a dma_unmap callback op in their driver ops and rely on
the core code to wire it up.
Suggested-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/gpu/drm/i915/gvt/gvt.h | 1 -
drivers/gpu/drm/i915/gvt/kvmgt.c | 75 ++++-----------
drivers/s390/cio/vfio_ccw_ops.c | 41 ++-------
drivers/s390/cio/vfio_ccw_private.h | 1 -
drivers/s390/crypto/vfio_ap_ops.c | 53 ++---------
drivers/s390/crypto/vfio_ap_private.h | 3 -
drivers/vfio/vfio.c | 126 +++++++++-----------------
drivers/vfio/vfio.h | 5 +
include/linux/vfio.h | 21 +----
9 files changed, 87 insertions(+), 239 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index aee1a45da74bcb..705689e6401197 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -226,7 +226,6 @@ struct intel_vgpu {
unsigned long nr_cache_entries;
struct mutex cache_lock;
- struct notifier_block iommu_notifier;
atomic_t released;
struct kvm_page_track_notifier_node track_node;
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index e2f6c56ab3420c..ecd5bb37b63a2a 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -729,34 +729,25 @@ int intel_gvt_set_edid(struct intel_vgpu *vgpu, int port_num)
return ret;
}
-static int intel_vgpu_iommu_notifier(struct notifier_block *nb,
- unsigned long action, void *data)
+static void intel_vgpu_dma_unmap(struct vfio_device *vfio_dev, u64 iova,
+ u64 length)
{
- struct intel_vgpu *vgpu =
- container_of(nb, struct intel_vgpu, iommu_notifier);
-
- if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
- struct vfio_iommu_type1_dma_unmap *unmap = data;
- struct gvt_dma *entry;
- unsigned long iov_pfn, end_iov_pfn;
+ struct intel_vgpu *vgpu = vfio_dev_to_vgpu(vfio_dev);
+ struct gvt_dma *entry;
+ u64 iov_pfn = iova >> PAGE_SHIFT;
+ u64 end_iov_pfn = iov_pfn + length / PAGE_SIZE;
- iov_pfn = unmap->iova >> PAGE_SHIFT;
- end_iov_pfn = iov_pfn + unmap->size / PAGE_SIZE;
+ mutex_lock(&vgpu->cache_lock);
+ for (; iov_pfn < end_iov_pfn; iov_pfn++) {
+ entry = __gvt_cache_find_gfn(vgpu, iov_pfn);
+ if (!entry)
+ continue;
- mutex_lock(&vgpu->cache_lock);
- for (; iov_pfn < end_iov_pfn; iov_pfn++) {
- entry = __gvt_cache_find_gfn(vgpu, iov_pfn);
- if (!entry)
- continue;
-
- gvt_dma_unmap_page(vgpu, entry->gfn, entry->dma_addr,
- entry->size);
- __gvt_cache_remove_entry(vgpu, entry);
- }
- mutex_unlock(&vgpu->cache_lock);
+ gvt_dma_unmap_page(vgpu, entry->gfn, entry->dma_addr,
+ entry->size);
+ __gvt_cache_remove_entry(vgpu, entry);
}
-
- return NOTIFY_OK;
+ mutex_unlock(&vgpu->cache_lock);
}
static bool __kvmgt_vgpu_exist(struct intel_vgpu *vgpu)
@@ -783,36 +774,20 @@ static bool __kvmgt_vgpu_exist(struct intel_vgpu *vgpu)
static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
{
struct intel_vgpu *vgpu = vfio_dev_to_vgpu(vfio_dev);
- unsigned long events;
- int ret;
-
- vgpu->iommu_notifier.notifier_call = intel_vgpu_iommu_notifier;
- events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
- ret = vfio_register_notifier(vfio_dev, VFIO_IOMMU_NOTIFY, &events,
- &vgpu->iommu_notifier);
- if (ret != 0) {
- gvt_vgpu_err("vfio_register_notifier for iommu failed: %d\n",
- ret);
- goto out;
- }
-
- ret = -EEXIST;
if (vgpu->attached)
- goto undo_iommu;
+ return -EEXIST;
- ret = -ESRCH;
if (!vgpu->vfio_device.kvm ||
vgpu->vfio_device.kvm->mm != current->mm) {
gvt_vgpu_err("KVM is required to use Intel vGPU\n");
- goto undo_iommu;
+ return -ESRCH;
}
kvm_get_kvm(vgpu->vfio_device.kvm);
- ret = -EEXIST;
if (__kvmgt_vgpu_exist(vgpu))
- goto undo_iommu;
+ return -EEXIST;
vgpu->attached = true;
@@ -831,12 +806,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
atomic_set(&vgpu->released, 0);
return 0;
-
-undo_iommu:
- vfio_unregister_notifier(vfio_dev, VFIO_IOMMU_NOTIFY,
- &vgpu->iommu_notifier);
-out:
- return ret;
}
static void intel_vgpu_release_msi_eventfd_ctx(struct intel_vgpu *vgpu)
@@ -853,8 +822,6 @@ static void intel_vgpu_release_msi_eventfd_ctx(struct intel_vgpu *vgpu)
static void intel_vgpu_close_device(struct vfio_device *vfio_dev)
{
struct intel_vgpu *vgpu = vfio_dev_to_vgpu(vfio_dev);
- struct drm_i915_private *i915 = vgpu->gvt->gt->i915;
- int ret;
if (!vgpu->attached)
return;
@@ -864,11 +831,6 @@ static void intel_vgpu_close_device(struct vfio_device *vfio_dev)
intel_gvt_release_vgpu(vgpu);
- ret = vfio_unregister_notifier(&vgpu->vfio_device, VFIO_IOMMU_NOTIFY,
- &vgpu->iommu_notifier);
- drm_WARN(&i915->drm, ret,
- "vfio_unregister_notifier for iommu failed: %d\n", ret);
-
debugfs_remove(debugfs_lookup(KVMGT_DEBUGFS_FILENAME, vgpu->debugfs));
kvm_page_track_unregister_notifier(vgpu->vfio_device.kvm,
@@ -1610,6 +1572,7 @@ static const struct vfio_device_ops intel_vgpu_dev_ops = {
.write = intel_vgpu_write,
.mmap = intel_vgpu_mmap,
.ioctl = intel_vgpu_ioctl,
+ .dma_unmap = intel_vgpu_dma_unmap,
};
static int intel_vgpu_probe(struct mdev_device *mdev)
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index b49e2e9db2dc6f..09e0ce7b72324c 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -44,31 +44,19 @@ static int vfio_ccw_mdev_reset(struct vfio_ccw_private *private)
return ret;
}
-static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
- unsigned long action,
- void *data)
+static void vfio_ccw_dma_unmap(struct vfio_device *vdev, u64 iova, u64 length)
{
struct vfio_ccw_private *private =
- container_of(nb, struct vfio_ccw_private, nb);
-
- /*
- * Vendor drivers MUST unpin pages in response to an
- * invalidation.
- */
- if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
- struct vfio_iommu_type1_dma_unmap *unmap = data;
-
- if (!cp_iova_pinned(&private->cp, unmap->iova))
- return NOTIFY_OK;
+ container_of(vdev, struct vfio_ccw_private, vdev);
- if (vfio_ccw_mdev_reset(private))
- return NOTIFY_BAD;
+ /* Drivers MUST unpin pages in response to an invalidation. */
+ if (!cp_iova_pinned(&private->cp, iova))
+ return;
- cp_free(&private->cp);
- return NOTIFY_OK;
- }
+ if (vfio_ccw_mdev_reset(private))
+ return;
- return NOTIFY_DONE;
+ cp_free(&private->cp);
}
static ssize_t name_show(struct mdev_type *mtype,
@@ -178,19 +166,11 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
{
struct vfio_ccw_private *private =
container_of(vdev, struct vfio_ccw_private, vdev);
- unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
int ret;
- private->nb.notifier_call = vfio_ccw_mdev_notifier;
-
- ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY,
- &events, &private->nb);
- if (ret)
- return ret;
-
ret = vfio_ccw_register_async_dev_regions(private);
if (ret)
- goto out_unregister;
+ return ret;
ret = vfio_ccw_register_schib_dev_regions(private);
if (ret)
@@ -204,7 +184,6 @@ static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
out_unregister:
vfio_ccw_unregister_dev_regions(private);
- vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
return ret;
}
@@ -222,7 +201,6 @@ static void vfio_ccw_mdev_close_device(struct vfio_device *vdev)
cp_free(&private->cp);
vfio_ccw_unregister_dev_regions(private);
- vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY, &private->nb);
}
static ssize_t vfio_ccw_mdev_read_io_region(struct vfio_ccw_private *private,
@@ -645,6 +623,7 @@ static const struct vfio_device_ops vfio_ccw_dev_ops = {
.write = vfio_ccw_mdev_write,
.ioctl = vfio_ccw_mdev_ioctl,
.request = vfio_ccw_mdev_request,
+ .dma_unmap = vfio_ccw_dma_unmap,
};
struct mdev_driver vfio_ccw_mdev_driver = {
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index 7272eb78861244..2627791c9006d4 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -98,7 +98,6 @@ struct vfio_ccw_private {
struct completion *completion;
atomic_t avail;
struct mdev_device *mdev;
- struct notifier_block nb;
struct ccw_io_region *io_region;
struct mutex io_mutex;
struct vfio_ccw_region *region;
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index a7d2a95796d360..bb1a1677c5c230 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1226,34 +1226,14 @@ static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev,
return 0;
}
-/**
- * vfio_ap_mdev_iommu_notifier - IOMMU notifier callback
- *
- * @nb: The notifier block
- * @action: Action to be taken
- * @data: data associated with the request
- *
- * For an UNMAP request, unpin the guest IOVA (the NIB guest address we
- * pinned before). Other requests are ignored.
- *
- * Return: for an UNMAP request, NOFITY_OK; otherwise NOTIFY_DONE.
- */
-static int vfio_ap_mdev_iommu_notifier(struct notifier_block *nb,
- unsigned long action, void *data)
+static void vfio_ap_mdev_dma_unmap(struct vfio_device *vdev, u64 iova,
+ u64 length)
{
- struct ap_matrix_mdev *matrix_mdev;
-
- matrix_mdev = container_of(nb, struct ap_matrix_mdev, iommu_notifier);
-
- if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
- struct vfio_iommu_type1_dma_unmap *unmap = data;
- unsigned long g_pfn = unmap->iova >> PAGE_SHIFT;
-
- vfio_unpin_pages(&matrix_mdev->vdev, &g_pfn, 1);
- return NOTIFY_OK;
- }
+ struct ap_matrix_mdev *matrix_mdev =
+ container_of(vdev, struct ap_matrix_mdev, vdev);
+ unsigned long g_pfn = iova >> PAGE_SHIFT;
- return NOTIFY_DONE;
+ vfio_unpin_pages(&matrix_mdev->vdev, &g_pfn, 1);
}
/**
@@ -1380,27 +1360,11 @@ static int vfio_ap_mdev_open_device(struct vfio_device *vdev)
{
struct ap_matrix_mdev *matrix_mdev =
container_of(vdev, struct ap_matrix_mdev, vdev);
- unsigned long events;
- int ret;
if (!vdev->kvm)
return -EINVAL;
- ret = vfio_ap_mdev_set_kvm(matrix_mdev, vdev->kvm);
- if (ret)
- return ret;
-
- matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier;
- events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
- ret = vfio_register_notifier(vdev, VFIO_IOMMU_NOTIFY, &events,
- &matrix_mdev->iommu_notifier);
- if (ret)
- goto err_kvm;
- return 0;
-
-err_kvm:
- vfio_ap_mdev_unset_kvm(matrix_mdev);
- return ret;
+ return vfio_ap_mdev_set_kvm(matrix_mdev, vdev->kvm);
}
static void vfio_ap_mdev_close_device(struct vfio_device *vdev)
@@ -1408,8 +1372,6 @@ static void vfio_ap_mdev_close_device(struct vfio_device *vdev)
struct ap_matrix_mdev *matrix_mdev =
container_of(vdev, struct ap_matrix_mdev, vdev);
- vfio_unregister_notifier(vdev, VFIO_IOMMU_NOTIFY,
- &matrix_mdev->iommu_notifier);
vfio_ap_mdev_unset_kvm(matrix_mdev);
}
@@ -1461,6 +1423,7 @@ static const struct vfio_device_ops vfio_ap_matrix_dev_ops = {
.open_device = vfio_ap_mdev_open_device,
.close_device = vfio_ap_mdev_close_device,
.ioctl = vfio_ap_mdev_ioctl,
+ .dma_unmap = vfio_ap_mdev_dma_unmap,
};
static struct mdev_driver vfio_ap_matrix_driver = {
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index a26efd804d0df3..abb59d59f81b20 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -81,8 +81,6 @@ struct ap_matrix {
* @node: allows the ap_matrix_mdev struct to be added to a list
* @matrix: the adapters, usage domains and control domains assigned to the
* mediated matrix device.
- * @iommu_notifier: notifier block used for specifying callback function for
- * handling the VFIO_IOMMU_NOTIFY_DMA_UNMAP even
* @kvm: the struct holding guest's state
* @pqap_hook: the function pointer to the interception handler for the
* PQAP(AQIC) instruction.
@@ -92,7 +90,6 @@ struct ap_matrix_mdev {
struct vfio_device vdev;
struct list_head node;
struct ap_matrix matrix;
- struct notifier_block iommu_notifier;
struct kvm *kvm;
crypto_hook pqap_hook;
struct mdev_device *mdev;
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 61e71c1154be67..f005b644ab9e69 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1077,8 +1077,20 @@ static void vfio_device_unassign_container(struct vfio_device *device)
up_write(&device->group->group_rwsem);
}
+static int vfio_iommu_notifier(struct notifier_block *nb, unsigned long action,
+ void *data)
+{
+ struct vfio_device *vfio_device =
+ container_of(nb, struct vfio_device, iommu_nb);
+ struct vfio_iommu_type1_dma_unmap *unmap = data;
+
+ vfio_device->ops->dma_unmap(vfio_device, unmap->iova, unmap->size);
+ return NOTIFY_OK;
+}
+
static struct file *vfio_device_open(struct vfio_device *device)
{
+ struct vfio_iommu_driver *iommu_driver;
struct file *filep;
int ret;
@@ -1109,6 +1121,18 @@ static struct file *vfio_device_open(struct vfio_device *device)
if (ret)
goto err_undo_count;
}
+
+ iommu_driver = device->group->container->iommu_driver;
+ if (device->ops->dma_unmap && iommu_driver &&
+ iommu_driver->ops->register_notifier) {
+ unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP;
+
+ device->iommu_nb.notifier_call = vfio_iommu_notifier;
+ iommu_driver->ops->register_notifier(
+ device->group->container->iommu_data, &events,
+ &device->iommu_nb);
+ }
+
up_read(&device->group->group_rwsem);
}
mutex_unlock(&device->dev_set->lock);
@@ -1143,8 +1167,16 @@ static struct file *vfio_device_open(struct vfio_device *device)
err_close_device:
mutex_lock(&device->dev_set->lock);
down_read(&device->group->group_rwsem);
- if (device->open_count == 1 && device->ops->close_device)
+ if (device->open_count == 1 && device->ops->close_device) {
device->ops->close_device(device);
+
+ iommu_driver = device->group->container->iommu_driver;
+ if (device->ops->dma_unmap && iommu_driver &&
+ iommu_driver->ops->register_notifier)
+ iommu_driver->ops->unregister_notifier(
+ device->group->container->iommu_data,
+ &device->iommu_nb);
+ }
err_undo_count:
device->open_count--;
if (device->open_count == 0 && device->kvm)
@@ -1339,12 +1371,20 @@ static const struct file_operations vfio_group_fops = {
static int vfio_device_fops_release(struct inode *inode, struct file *filep)
{
struct vfio_device *device = filep->private_data;
+ struct vfio_iommu_driver *iommu_driver;
mutex_lock(&device->dev_set->lock);
vfio_assert_device_open(device);
down_read(&device->group->group_rwsem);
if (device->open_count == 1 && device->ops->close_device)
device->ops->close_device(device);
+
+ iommu_driver = device->group->container->iommu_driver;
+ if (device->ops->dma_unmap && iommu_driver &&
+ iommu_driver->ops->register_notifier)
+ iommu_driver->ops->unregister_notifier(
+ device->group->container->iommu_data,
+ &device->iommu_nb);
up_read(&device->group->group_rwsem);
device->open_count--;
if (device->open_count == 0)
@@ -2027,90 +2067,6 @@ int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova, void *data,
}
EXPORT_SYMBOL(vfio_dma_rw);
-static int vfio_register_iommu_notifier(struct vfio_group *group,
- unsigned long *events,
- struct notifier_block *nb)
-{
- struct vfio_container *container;
- struct vfio_iommu_driver *driver;
- int ret;
-
- lockdep_assert_held_read(&group->group_rwsem);
-
- container = group->container;
- driver = container->iommu_driver;
- if (likely(driver && driver->ops->register_notifier))
- ret = driver->ops->register_notifier(container->iommu_data,
- events, nb);
- else
- ret = -ENOTTY;
-
- return ret;
-}
-
-static int vfio_unregister_iommu_notifier(struct vfio_group *group,
- struct notifier_block *nb)
-{
- struct vfio_container *container;
- struct vfio_iommu_driver *driver;
- int ret;
-
- lockdep_assert_held_read(&group->group_rwsem);
-
- container = group->container;
- driver = container->iommu_driver;
- if (likely(driver && driver->ops->unregister_notifier))
- ret = driver->ops->unregister_notifier(container->iommu_data,
- nb);
- else
- ret = -ENOTTY;
-
- return ret;
-}
-
-int vfio_register_notifier(struct vfio_device *device,
- enum vfio_notify_type type, unsigned long *events,
- struct notifier_block *nb)
-{
- struct vfio_group *group = device->group;
- int ret;
-
- if (!nb || !events || (*events == 0) ||
- !vfio_assert_device_open(device))
- return -EINVAL;
-
- switch (type) {
- case VFIO_IOMMU_NOTIFY:
- ret = vfio_register_iommu_notifier(group, events, nb);
- break;
- default:
- ret = -EINVAL;
- }
- return ret;
-}
-EXPORT_SYMBOL(vfio_register_notifier);
-
-int vfio_unregister_notifier(struct vfio_device *device,
- enum vfio_notify_type type,
- struct notifier_block *nb)
-{
- struct vfio_group *group = device->group;
- int ret;
-
- if (!nb || !vfio_assert_device_open(device))
- return -EINVAL;
-
- switch (type) {
- case VFIO_IOMMU_NOTIFY:
- ret = vfio_unregister_iommu_notifier(group, nb);
- break;
- default:
- ret = -EINVAL;
- }
- return ret;
-}
-EXPORT_SYMBOL(vfio_unregister_notifier);
-
/*
* Module/class support
*/
diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index a6713022115155..cb2e4e9baa8fe8 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -33,6 +33,11 @@ enum vfio_iommu_notify_type {
VFIO_IOMMU_CONTAINER_CLOSE = 0,
};
+/* events for register_notifier() */
+enum {
+ VFIO_IOMMU_NOTIFY_DMA_UNMAP = 1,
+};
+
/**
* struct vfio_iommu_driver_ops - VFIO IOMMU driver callbacks
*/
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index aa888cc517578e..b76623e3b92fca 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -44,6 +44,7 @@ struct vfio_device {
unsigned int open_count;
struct completion comp;
struct list_head group_next;
+ struct notifier_block iommu_nb;
};
/**
@@ -60,6 +61,8 @@ struct vfio_device {
* @match: Optional device name match callback (return: 0 for no-match, >0 for
* match, -errno for abort (ex. match with insufficient or incorrect
* additional args)
+ * @dma_unmap: Called when userspace unmaps IOVA from the container
+ * this device is attached to.
* @device_feature: Optional, fill in the VFIO_DEVICE_FEATURE ioctl
* @migration_set_state: Optional callback to change the migration state for
* devices that support migration. It's mandatory for
@@ -85,6 +88,7 @@ struct vfio_device_ops {
int (*mmap)(struct vfio_device *vdev, struct vm_area_struct *vma);
void (*request)(struct vfio_device *vdev, unsigned int count);
int (*match)(struct vfio_device *vdev, char *buf);
+ void (*dma_unmap)(struct vfio_device *vdev, u64 iova, u64 length);
int (*device_feature)(struct vfio_device *device, u32 flags,
void __user *arg, size_t argsz);
struct file *(*migration_set_state)(
@@ -154,23 +158,6 @@ extern int vfio_unpin_pages(struct vfio_device *device, unsigned long *user_pfn,
extern int vfio_dma_rw(struct vfio_device *device, dma_addr_t user_iova,
void *data, size_t len, bool write);
-/* each type has independent events */
-enum vfio_notify_type {
- VFIO_IOMMU_NOTIFY = 0,
-};
-
-/* events for VFIO_IOMMU_NOTIFY */
-#define VFIO_IOMMU_NOTIFY_DMA_UNMAP BIT(0)
-
-extern int vfio_register_notifier(struct vfio_device *device,
- enum vfio_notify_type type,
- unsigned long *required_events,
- struct notifier_block *nb);
-extern int vfio_unregister_notifier(struct vfio_device *device,
- enum vfio_notify_type type,
- struct notifier_block *nb);
-
-
/*
* Sub-module helpers
*/
