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Message-ID: <161315805248.7320.13358719859656681660.stgit@gimli.home>
Date: Fri, 12 Feb 2021 12:27:39 -0700
From: Alex Williamson <alex.williamson@...hat.com>
To: alex.williamson@...hat.com
Cc: cohuck@...hat.com, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org, jgg@...dia.com, peterx@...hat.com
Subject: [PATCH 1/3] vfio: Introduce vma ops registration and notifier
Create an interface through vfio-core where a vfio bus driver (ex.
vfio-pci) can register the vm_operations_struct it uses to map device
memory, along with a set of registration callbacks. This allows
vfio-core to expose interfaces for IOMMU backends to match a
vm_area_struct to a bus driver and register a notifier for relavant
changes to the device mapping. For now we define only a notifier
action for closing the device.
Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
---
drivers/vfio/vfio.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/vfio.h | 20 ++++++++
2 files changed, 140 insertions(+)
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 38779e6fd80c..568f5e37a95f 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -47,6 +47,8 @@ static struct vfio {
struct cdev group_cdev;
dev_t group_devt;
wait_queue_head_t release_q;
+ struct list_head vm_ops_list;
+ struct mutex vm_ops_lock;
} vfio;
struct vfio_iommu_driver {
@@ -2354,6 +2356,121 @@ struct iommu_domain *vfio_group_iommu_domain(struct vfio_group *group)
}
EXPORT_SYMBOL_GPL(vfio_group_iommu_domain);
+struct vfio_vma_ops {
+ const struct vm_operations_struct *vm_ops;
+ vfio_register_vma_nb_t *reg_fn;
+ vfio_unregister_vma_nb_t *unreg_fn;
+ struct list_head next;
+};
+
+int vfio_register_vma_ops(const struct vm_operations_struct *vm_ops,
+ vfio_register_vma_nb_t *reg_fn,
+ vfio_unregister_vma_nb_t *unreg_fn)
+{
+ struct vfio_vma_ops *ops;
+ int ret = 0;
+
+ mutex_lock(&vfio.vm_ops_lock);
+ list_for_each_entry(ops, &vfio.vm_ops_list, next) {
+ if (ops->vm_ops == vm_ops) {
+ ret = -EEXIST;
+ goto out;
+ }
+ }
+
+ ops = kmalloc(sizeof(*ops), GFP_KERNEL);
+ if (!ops) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ops->vm_ops = vm_ops;
+ ops->reg_fn = reg_fn;
+ ops->unreg_fn = unreg_fn;
+
+ list_add(&ops->next, &vfio.vm_ops_list);
+out:
+ mutex_unlock(&vfio.vm_ops_lock);
+ return ret;
+
+}
+EXPORT_SYMBOL_GPL(vfio_register_vma_ops);
+
+void vfio_unregister_vma_ops(const struct vm_operations_struct *vm_ops)
+{
+ struct vfio_vma_ops *ops;
+
+ mutex_lock(&vfio.vm_ops_lock);
+ list_for_each_entry(ops, &vfio.vm_ops_list, next) {
+ if (ops->vm_ops == vm_ops) {
+ list_del(&ops->next);
+ kfree(ops);
+ break;
+ }
+ }
+ mutex_unlock(&vfio.vm_ops_lock);
+}
+EXPORT_SYMBOL_GPL(vfio_unregister_vma_ops);
+
+struct vfio_vma_obj {
+ const struct vm_operations_struct *vm_ops;
+ void *opaque;
+};
+
+void *vfio_register_vma_nb(struct vm_area_struct *vma,
+ struct notifier_block *nb)
+{
+ struct vfio_vma_ops *ops;
+ struct vfio_vma_obj *obj = ERR_PTR(-ENODEV);
+
+ mutex_lock(&vfio.vm_ops_lock);
+ list_for_each_entry(ops, &vfio.vm_ops_list, next) {
+ if (ops->vm_ops == vma->vm_ops) {
+ void *opaque;
+
+ obj = kmalloc(sizeof(*obj), GFP_KERNEL);
+ if (!obj) {
+ obj = ERR_PTR(-ENOMEM);
+ break;
+ }
+
+ obj->vm_ops = ops->vm_ops;
+
+ opaque = ops->reg_fn(vma, nb);
+ if (IS_ERR(opaque)) {
+ kfree(obj);
+ obj = opaque;
+ } else {
+ obj->opaque = opaque;
+ }
+
+ break;
+ }
+ }
+ mutex_unlock(&vfio.vm_ops_lock);
+
+ return obj;
+}
+EXPORT_SYMBOL_GPL(vfio_register_vma_nb);
+
+void vfio_unregister_vma_nb(void *opaque)
+{
+ struct vfio_vma_obj *obj = opaque;
+ struct vfio_vma_ops *ops;
+
+ mutex_lock(&vfio.vm_ops_lock);
+ list_for_each_entry(ops, &vfio.vm_ops_list, next) {
+ if (ops->vm_ops == obj->vm_ops) {
+ ops->unreg_fn(obj->opaque);
+ break;
+ }
+ }
+ mutex_unlock(&vfio.vm_ops_lock);
+
+ kfree(obj);
+}
+EXPORT_SYMBOL_GPL(vfio_unregister_vma_nb);
+
/**
* Module/class support
*/
@@ -2377,8 +2494,10 @@ static int __init vfio_init(void)
idr_init(&vfio.group_idr);
mutex_init(&vfio.group_lock);
mutex_init(&vfio.iommu_drivers_lock);
+ mutex_init(&vfio.vm_ops_lock);
INIT_LIST_HEAD(&vfio.group_list);
INIT_LIST_HEAD(&vfio.iommu_drivers_list);
+ INIT_LIST_HEAD(&vfio.vm_ops_list);
init_waitqueue_head(&vfio.release_q);
ret = misc_register(&vfio_dev);
@@ -2425,6 +2544,7 @@ static int __init vfio_init(void)
static void __exit vfio_cleanup(void)
{
WARN_ON(!list_empty(&vfio.group_list));
+ WARN_ON(!list_empty(&vfio.vm_ops_list));
#ifdef CONFIG_VFIO_NOIOMMU
vfio_unregister_iommu_driver(&vfio_noiommu_ops);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index b7e18bde5aa8..1b5c6179d869 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -137,6 +137,26 @@ extern int vfio_dma_rw(struct vfio_group *group, dma_addr_t user_iova,
extern struct iommu_domain *vfio_group_iommu_domain(struct vfio_group *group);
+typedef void *(vfio_register_vma_nb_t)(struct vm_area_struct *vma,
+ struct notifier_block *nb);
+typedef void (vfio_unregister_vma_nb_t)(void *opaque);
+
+extern int vfio_register_vma_ops(const struct vm_operations_struct *vm_ops,
+ vfio_register_vma_nb_t *reg_fn,
+ vfio_unregister_vma_nb_t *unreg_fn);
+
+extern void vfio_unregister_vma_ops(const struct vm_operations_struct *vm_ops);
+
+enum vfio_vma_notify_type {
+ VFIO_VMA_NOTIFY_CLOSE = 0,
+};
+
+extern void *vfio_register_vma_nb(struct vm_area_struct *vma,
+ struct notifier_block *nb);
+
+extern void vfio_unregister_vma_nb(void *opaque);
+
+
/* each type has independent events */
enum vfio_notify_type {
VFIO_IOMMU_NOTIFY = 0,
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