We can't pin PFNMAP IOMMU mappings like we can standard page-backed
mappings, therefore without an invalidation mechanism we can't know
if we should have revoked a user's mapping. Now that we have an
invalidation callback mechanism we can create an interface for vfio
bus drivers to indicate their support for invalidation by registering
supported vm_ops functions with vfio-core. A vfio IOMMU backend
driver can then test a vma against the registered vm_ops with this
support to determine whether to allow such a mapping. The type1
backend then adopts a new 'strict_mmio_maps' module option, enabled
by default, restricting IOMMU mapping of PFNMAP vmas to only those
supporting invalidation callbacks. vfio-pci is updated to register
vfio_pci_mmap_ops as supporting this feature.
Signed-off-by: Alex Williamson
---
drivers/vfio/pci/vfio_pci.c |7
drivers/vfio/vfio.c | 62 +++
drivers/vfio/vfio_iommu_type1.c |9 +-
include/linux/vfio.h|4 +++
4 files changed, 81 insertions(+), 1 deletion(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 100fe5f6bc22..dbfe6a11aa74 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -2281,6 +2281,7 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device
*vdev)
static void __exit vfio_pci_cleanup(void)
{
+ vfio_unregister_vma_inv_ops(_pci_mmap_ops);
pci_unregister_driver(_pci_driver);
vfio_pci_uninit_perm_bits();
}
@@ -2340,10 +2341,16 @@ static int __init vfio_pci_init(void)
if (ret)
goto out_driver;
+ ret = vfio_register_vma_inv_ops(_pci_mmap_ops);
+ if (ret)
+ goto out_inv_ops;
+
vfio_pci_fill_ids();
return 0;
+out_inv_ops:
+ pci_unregister_driver(_pci_driver);
out_driver:
vfio_pci_uninit_perm_bits();
return ret;
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 0fff057b7cd9..0f0a9d3b38aa 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_headvma_inv_ops_list;
+ struct mutexvma_inv_ops_lock;
} vfio;
struct vfio_iommu_driver {
@@ -98,6 +100,11 @@ struct vfio_device {
void*device_data;
};
+struct vfio_vma_inv_ops {
+ const struct vm_operations_struct *ops;
+ struct list_headops_next;
+};
+
#ifdef CONFIG_VFIO_NOIOMMU
static bool noiommu __read_mostly;
module_param_named(enable_unsafe_noiommu_mode,
@@ -2332,6 +2339,58 @@ int vfio_unregister_notifier(struct device *dev, enum
vfio_notify_type type,
}
EXPORT_SYMBOL(vfio_unregister_notifier);
+int vfio_register_vma_inv_ops(const struct vm_operations_struct *ops)
+{
+ struct vfio_vma_inv_ops *inv_ops;
+
+ inv_ops = kmalloc(sizeof(*inv_ops), GFP_KERNEL);
+ if (!inv_ops)
+ return -ENOMEM;
+
+ inv_ops->ops = ops;
+
+ mutex_lock(_inv_ops_lock);
+ list_add(_ops->ops_next, _inv_ops_list);
+ mutex_unlock(_inv_ops_lock);
+
+ return 0;
+}
+EXPORT_SYMBOL(vfio_register_vma_inv_ops);
+
+void vfio_unregister_vma_inv_ops(const struct vm_operations_struct *ops)
+{
+ struct vfio_vma_inv_ops *inv_ops;
+
+ mutex_lock(_inv_ops_lock);
+ list_for_each_entry(inv_ops, _inv_ops_list, ops_next) {
+ if (inv_ops->ops == ops) {
+ list_del(_ops->ops_next);
+ kfree(inv_ops);
+ break;
+ }
+ }
+ mutex_unlock(_inv_ops_lock);
+}
+EXPORT_SYMBOL(vfio_unregister_vma_inv_ops);
+
+bool vfio_vma_has_inv_ops(struct vm_area_struct *vma)
+{
+ struct vfio_vma_inv_ops *inv_ops;
+ bool ret = false;
+
+ mutex_lock(_inv_ops_lock);
+ list_for_each_entry(inv_ops, _inv_ops_list, ops_next) {
+ if (inv_ops->ops == vma->vm_ops) {
+ ret = true;
+ break;
+ }
+ }
+ mutex_unlock(_inv_ops_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_vma_has_inv_ops);
+
/**
* Module/class support
*/
@@ -2355,8 +2414,10 @@ static int __init vfio_init(void)
idr_init(_idr);
mutex_init(_lock);
mutex_init(_drivers_lock);
+ mutex_init(_inv_ops_lock);
INIT_LIST_HEAD(_list);
INIT_LIST_HEAD(_drivers_list);
+ INIT_LIST_HEAD(_inv_ops_list);
init_waitqueue_head(_q);
ret = misc_register(_dev);
@@ -2403,6 +2464,7 @@ static int __init vfio_init(void)
static void __exit vfio_cleanup(void)
{
WARN_ON(!list_empty(_list));
+ WARN_ON(!list_empty(_inv_ops_list));
#ifdef CONFIG_VFIO_NOIOMMU
