IB/mlx5: Extend CQ creation to get uar page index from user space

Extend CQ creation to get uar page index from user space, this mode can be
used with the UAR dynamic mode APIs to allocate/destroy a UAR object.

Link: https://lore.kernel.org/r/20200324060143.1569116-3-leon@kernel.orgSigned-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Michael Guralnik <michaelgur@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/cq.c

@@ -692,17 +692,19 @@ static int create_cq_user(struct mlx5_ib_dev *dev, struct ib_udata *udata,
 	struct mlx5_ib_ucontext *context = rdma_udata_to_drv_context(
 		udata, struct mlx5_ib_ucontext, ibucontext);
 
-	ucmdlen = udata->inlen < sizeof(ucmd) ?
-		  (sizeof(ucmd) - sizeof(ucmd.flags)) : sizeof(ucmd);
+	ucmdlen = min(udata->inlen, sizeof(ucmd));
+	if (ucmdlen < offsetof(struct mlx5_ib_create_cq, flags))
+		return -EINVAL;
 
 	if (ib_copy_from_udata(&ucmd, udata, ucmdlen))
 		return -EFAULT;
 
-	if (ucmdlen == sizeof(ucmd) &&
-	    (ucmd.flags & ~(MLX5_IB_CREATE_CQ_FLAGS_CQE_128B_PAD)))
+	if ((ucmd.flags & ~(MLX5_IB_CREATE_CQ_FLAGS_CQE_128B_PAD |
+			    MLX5_IB_CREATE_CQ_FLAGS_UAR_PAGE_INDEX)))
 		return -EINVAL;
 
-	if (ucmd.cqe_size != 64 && ucmd.cqe_size != 128)
+	if ((ucmd.cqe_size != 64 && ucmd.cqe_size != 128) ||
+	    ucmd.reserved0 || ucmd.reserved1)
 		return -EINVAL;
 
 	*cqe_size = ucmd.cqe_size;
@@ -739,7 +741,10 @@ static int create_cq_user(struct mlx5_ib_dev *dev, struct ib_udata *udata,
 	MLX5_SET(cqc, cqc, log_page_size,
 		 page_shift - MLX5_ADAPTER_PAGE_SHIFT);
 
-	*index = context->bfregi.sys_pages[0];
+	if (ucmd.flags & MLX5_IB_CREATE_CQ_FLAGS_UAR_PAGE_INDEX)
+		*index = ucmd.uar_page_index;
+	else
+		*index = context->bfregi.sys_pages[0];
 
 	if (ucmd.cqe_comp_en == 1) {
 		int mini_cqe_format;

include/uapi/rdma/mlx5-abi.h

@@ -266,6 +266,7 @@ struct mlx5_ib_query_device_resp {
 
 enum mlx5_ib_create_cq_flags {
 	MLX5_IB_CREATE_CQ_FLAGS_CQE_128B_PAD	= 1 << 0,
+	MLX5_IB_CREATE_CQ_FLAGS_UAR_PAGE_INDEX  = 1 << 1,
 };
 
 struct mlx5_ib_create_cq {
@@ -275,6 +276,9 @@ struct mlx5_ib_create_cq {
 	__u8    cqe_comp_en;
 	__u8    cqe_comp_res_format;
 	__u16	flags;
+	__u16	uar_page_index;
+	__u16	reserved0;
+	__u32	reserved1;
 };
 
 struct mlx5_ib_create_cq_resp {