@@ -509,11 +509,23 @@ int iommufd_access_set_ioas(struct iommufd_access *access, u32 ioas_id)
iommufd_ref_to_users(obj);
}
+ /*
+ * Set ioas to NULL to block any further iommufd_access_pin_pages().
+ * iommufd_access_unpin_pages() can continue using access->ioas_unpin.
+ */
+ access->ioas = NULL;
+
if (cur_ioas) {
+ if (new_ioas) {
+ mutex_unlock(&access->ioas_lock);
+ access->ops->unmap(access->data, 0, ULONG_MAX);
+ mutex_lock(&access->ioas_lock);
+ }
iopt_remove_access(&cur_ioas->iopt, access);
refcount_dec(&cur_ioas->obj.users);
}
+ access->ioas_unpin = new_ioas;
access->ioas = new_ioas;
mutex_unlock(&access->ioas_lock);
@@ -527,6 +539,18 @@ int iommufd_access_set_ioas(struct iommufd_access *access, u32 ioas_id)
}
EXPORT_SYMBOL_NS_GPL(iommufd_access_set_ioas, IOMMUFD);
+bool iommufd_access_ioas_is_attached(struct iommufd_access *access)
+{
+ bool attached;
+
+ mutex_lock(&access->ioas_lock);
+ attached = !!access->ioas;
+ mutex_unlock(&access->ioas_lock);
+
+ return attached;
+}
+EXPORT_SYMBOL_NS_GPL(iommufd_access_ioas_is_attached, IOMMUFD);
+
/**
* iommufd_access_notify_unmap - Notify users of an iopt to stop using it
* @iopt: iopt to work on
@@ -587,11 +611,11 @@ void iommufd_access_unpin_pages(struct iommufd_access *access,
return;
mutex_lock(&access->ioas_lock);
- if (!access->ioas) {
+ if (!access->ioas_unpin) {
mutex_unlock(&access->ioas_lock);
return;
}
- iopt = &access->ioas->iopt;
+ iopt = &access->ioas_unpin->iopt;
down_read(&iopt->iova_rwsem);
iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova)
@@ -261,6 +261,7 @@ struct iommufd_access {
struct iommufd_object obj;
struct iommufd_ctx *ictx;
struct iommufd_ioas *ioas;
+ struct iommufd_ioas *ioas_unpin;
struct mutex ioas_lock;
const struct iommufd_access_ops *ops;
void *data;
@@ -187,6 +187,10 @@ int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id)
if (!vdev->iommufd_access)
return -ENOENT;
+ if (!vdev->ops->dma_unmap && pt_id &&
+ iommufd_access_ioas_is_attached(vdev->iommufd_access))
+ return -EBUSY;
+
iommufd_access_set_ioas(vdev->iommufd_access, *pt_id);
return 0;
}
@@ -44,6 +44,7 @@ iommufd_access_create(struct iommufd_ctx *ictx,
const struct iommufd_access_ops *ops, void *data);
void iommufd_access_destroy(struct iommufd_access *access);
int iommufd_access_set_ioas(struct iommufd_access *access, u32 ioas_id);
+bool iommufd_access_ioas_is_attached(struct iommufd_access *access);
void iommufd_ctx_get(struct iommufd_ctx *ictx);
Support an access->ioas replacement in iommufd_access_set_ioas(), which sets the access->ioas to NULL provisionally so that any further incoming iommufd_access_pin_pages() callback can be blocked. Then, call access->ops->unmap() to clean up the entire iopt. To allow an iommufd_access_unpin_pages() callback to happen via this unmap() call, add an ioas_unpin pointer so the unpin routine won't be affected by the "access->ioas = NULL" trick above. Also, a vdev without an ops->dma_unmap implementation cannot replace its access->ioas pointer. So add an iommufd_access_ioas_is_attached() helper to sanity that. Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com> --- drivers/iommu/iommufd/device.c | 28 +++++++++++++++++++++++-- drivers/iommu/iommufd/iommufd_private.h | 1 + drivers/vfio/iommufd.c | 4 ++++ include/linux/iommufd.h | 1 + 4 files changed, 32 insertions(+), 2 deletions(-)