IB/mlx5: Add support for DEVX query UAR

Return a device UAR index for a given user index via the DEVX interface.

Security note:
The hardware protection mechanism works like this: Each device object that
is subject to UAR doorbells (QP/SQ/CQ) gets a UAR ID (called uar_page in
the device specification manual) upon its creation. Then upon doorbell,
hardware fetches the object context for which the doorbell was rang, and
validates that the UAR through which the DB was rang matches the UAR ID
of the object.

If no match the doorbell is silently ignored by the hardware.  Of
course, the user cannot ring a doorbell on a UAR that was not mapped to
it.

Now in devx, as the devx kernel does not manipulate the QP/SQ/CQ command
mailboxes (except tagging them with UID), we expose to the user its UAR
ID, so it can embed it in these objects in the expected specification
format. So the only thing the user can do is hurt itself by creating a
QP/SQ/CQ with a UAR ID other than his, and then in this case other users
may ring a doorbell on its objects.

The consequence of that will be that another user can schedule a QP/SQ
of the buggy user for execution (just insert it to the hardware schedule
queue or arm its CQ for event generation), no further harm is expected.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
index bb5e40a9edd82e904486e51e79dabf7c0c3ec15f..9b1804eb9924ec04da73cdcd71d9b4862d3baac1 100644 (file)
--- a/drivers/infiniband/hw/mlx5/devx.c
+++ b/drivers/infiniband/hw/mlx5/devx.c
@@ -373,6 +373,50 @@ static bool devx_is_general_cmd(void *in)
        }
 }
 
+/*
+ *Security note:
+ * The hardware protection mechanism works like this: Each device object that
+ * is subject to UAR doorbells (QP/SQ/CQ) gets a UAR ID (called uar_page in
+ * the device specification manual) upon its creation. Then upon doorbell,
+ * hardware fetches the object context for which the doorbell was rang, and
+ * validates that the UAR through which the DB was rang matches the UAR ID
+ * of the object.
+ * If no match the doorbell is silently ignored by the hardware. Of course,
+ * the user cannot ring a doorbell on a UAR that was not mapped to it.
+ * Now in devx, as the devx kernel does not manipulate the QP/SQ/CQ command
+ * mailboxes (except tagging them with UID), we expose to the user its UAR
+ * ID, so it can embed it in these objects in the expected specification
+ * format. So the only thing the user can do is hurt itself by creating a
+ * QP/SQ/CQ with a UAR ID other than his, and then in this case other users
+ * may ring a doorbell on its objects.
+ * The consequence of that will be that another user can schedule a QP/SQ
+ * of the buggy user for execution (just insert it to the hardware schedule
+ * queue or arm its CQ for event generation), no further harm is expected.
+ */
+static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_QUERY_UAR)(struct ib_device *ib_dev,
+                                 struct ib_uverbs_file *file,
+                                 struct uverbs_attr_bundle *attrs)
+{
+       struct mlx5_ib_ucontext *c = devx_ufile2uctx(file);
+       u32 user_idx;
+       s32 dev_idx;
+
+       if (uverbs_copy_from(&user_idx, attrs,
+                            MLX5_IB_ATTR_DEVX_QUERY_UAR_USER_IDX))
+               return -EFAULT;
+
+       dev_idx = bfregn_to_uar_index(to_mdev(ib_dev),
+                                     &c->bfregi, user_idx, true);
+       if (dev_idx < 0)
+               return dev_idx;
+
+       if (uverbs_copy_to(attrs, MLX5_IB_ATTR_DEVX_QUERY_UAR_DEV_IDX,
+                          &dev_idx, sizeof(dev_idx)))
+               return -EFAULT;
+
+       return 0;
+}
+
 static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OTHER)(struct ib_device *ib_dev,
                                  struct ib_uverbs_file *file,
                                  struct uverbs_attr_bundle *attrs)
@@ -744,6 +788,12 @@ other_cmd_free:
        return err;
 }
 
+static DECLARE_UVERBS_NAMED_METHOD(MLX5_IB_METHOD_DEVX_QUERY_UAR,
+       &UVERBS_ATTR_PTR_IN(MLX5_IB_ATTR_DEVX_QUERY_UAR_USER_IDX, UVERBS_ATTR_TYPE(u32),
+                           UA_FLAGS(UVERBS_ATTR_SPEC_F_MANDATORY)),
+       &UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_DEVX_QUERY_UAR_DEV_IDX, UVERBS_ATTR_TYPE(u32),
+                            UA_FLAGS(UVERBS_ATTR_SPEC_F_MANDATORY)));
+
 static DECLARE_UVERBS_NAMED_METHOD(MLX5_IB_METHOD_DEVX_OTHER,
        &UVERBS_ATTR_PTR_IN_SZ(MLX5_IB_ATTR_DEVX_OTHER_CMD_IN,
                               UVERBS_ATTR_MIN_SIZE(MLX5_ST_SZ_BYTES(general_obj_in_cmd_hdr)),
@@ -808,7 +858,8 @@ static DECLARE_UVERBS_NAMED_METHOD(MLX5_IB_METHOD_DEVX_OBJ_QUERY,
                                         UVERBS_ATTR_SPEC_F_MIN_SZ_OR_ZERO)));
 
 static DECLARE_UVERBS_GLOBAL_METHODS(MLX5_IB_OBJECT_DEVX,
-       &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_OTHER));
+       &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_OTHER),
+       &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_QUERY_UAR));
 
 static DECLARE_UVERBS_NAMED_OBJECT(MLX5_IB_OBJECT_DEVX_OBJ,
        &UVERBS_TYPE_ALLOC_IDR(0, devx_obj_cleanup),

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 1c857dd3c77f647f9810f19bd660b4001f71fe6d..e45f364622eb1cbb30896f25ba81bbdc2f074716 100644 (file)
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -1329,4 +1329,7 @@ static inline int get_num_static_uars(struct mlx5_ib_dev *dev,
 unsigned long mlx5_ib_get_xlt_emergency_page(void);
 void mlx5_ib_put_xlt_emergency_page(void);
 
+int bfregn_to_uar_index(struct mlx5_ib_dev *dev,
+                       struct mlx5_bfreg_info *bfregi, int bfregn,
+                       bool dyn_bfreg);
 #endif /* MLX5_IB_H */

diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index e3c4ab9be41d4e0011a77b0293642c530b700ac7..d5f072c50ee5fca9cc393b758a4f811c7c6386a2 100644 (file)
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -641,9 +641,9 @@ static void mlx5_ib_lock_cqs(struct mlx5_ib_cq *send_cq,
 static void mlx5_ib_unlock_cqs(struct mlx5_ib_cq *send_cq,
                               struct mlx5_ib_cq *recv_cq);
 
-static int bfregn_to_uar_index(struct mlx5_ib_dev *dev,
-                              struct mlx5_bfreg_info *bfregi, int bfregn,
-                              bool dyn_bfreg)
+int bfregn_to_uar_index(struct mlx5_ib_dev *dev,
+                       struct mlx5_bfreg_info *bfregi, int bfregn,
+                       bool dyn_bfreg)
 {
        int bfregs_per_sys_page;
        int index_of_sys_page;
@@ -653,6 +653,9 @@ static int bfregn_to_uar_index(struct mlx5_ib_dev *dev,
                                MLX5_NON_FP_BFREGS_PER_UAR;
        index_of_sys_page = bfregn / bfregs_per_sys_page;
 
+       if (index_of_sys_page >= bfregi->num_sys_pages)
+               return -EINVAL;
+
        if (dyn_bfreg) {
                index_of_sys_page += bfregi->num_static_sys_pages;
                if (bfregn > bfregi->num_dyn_bfregs ||

diff --git a/include/uapi/rdma/mlx5_user_ioctl_cmds.h b/include/uapi/rdma/mlx5_user_ioctl_cmds.h
index 97d216b8d05360706cb1f2c6e365c25c07b35661..1252695cd94b5f50d007065676faa381006a6f02 100644 (file)
--- a/include/uapi/rdma/mlx5_user_ioctl_cmds.h
+++ b/include/uapi/rdma/mlx5_user_ioctl_cmds.h
@@ -47,6 +47,7 @@ enum mlx5_ib_alloc_dm_attrs {
 
 enum mlx5_ib_devx_methods {
        MLX5_IB_METHOD_DEVX_OTHER  = (1U << UVERBS_ID_NS_SHIFT),
+       MLX5_IB_METHOD_DEVX_QUERY_UAR,
 };
 
 enum  mlx5_ib_devx_other_attrs {
@@ -60,6 +61,11 @@ enum mlx5_ib_devx_obj_create_attrs {
        MLX5_IB_ATTR_DEVX_OBJ_CREATE_CMD_OUT,
 };
 
+enum  mlx5_ib_devx_query_uar_attrs {
+       MLX5_IB_ATTR_DEVX_QUERY_UAR_USER_IDX = (1U << UVERBS_ID_NS_SHIFT),
+       MLX5_IB_ATTR_DEVX_QUERY_UAR_DEV_IDX,
+};
+
 enum mlx5_ib_devx_obj_destroy_attrs {
        MLX5_IB_ATTR_DEVX_OBJ_DESTROY_HANDLE = (1U << UVERBS_ID_NS_SHIFT),
 };