IB/mlx5: Allow future extension of libmlx5 input data

Current check requests that new fields in struct
mlx5_ib_alloc_ucontext_req_v2 that are not known to the driver be zero.
This was introduced so new libraries passing additional information to
the kernel through struct mlx5_ib_alloc_ucontext_req_v2 will be notified
by old kernels that do not support their request by failing the
operation. This schecme is problematic since it requires libmlx5 to issue
the requests with descending input size for struct
mlx5_ib_alloc_ucontext_req_v2.

To avoid this, we require that new features that will obey the following
rules:
If the feature requires one or more fields in the response and the at
least one of the fields can be encoded such that a zero value means the
kernel ignored the request then this field will provide the indication
to the library. If no response is required or if zero is a valid
response, a new field should be added that indicates to the library
whether its request was processed.

Fixes: b368d7c ('IB/mlx5: Add hca_core_clock_offset to udata in init_ucontext')
Signed-off-by: Eli Cohen <[email protected]>
Reviewed-by: Matan Barak <[email protected]>
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Saeed Mahameed <[email protected]>

Author: Eli Cohen

drivers/infiniband/hw/mlx5/cq.c

@@ -788,7 +788,7 @@ 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 = to_mucontext(context)->bfregi.uars[0].index;
+	*index = to_mucontext(context)->bfregi.sys_pages[0];
 
 	if (ucmd.cqe_comp_en == 1) {
 		if (unlikely((*cqe_size != 64) ||

drivers/infiniband/hw/mlx5/main.c

@@ -992,6 +992,80 @@ static int mlx5_ib_modify_port(struct ib_device *ibdev, u8 port, int mask,
 	return err;
 }
 
+static int calc_total_bfregs(struct mlx5_ib_dev *dev, bool lib_uar_4k,
+			     struct mlx5_ib_alloc_ucontext_req_v2 *req,
+			     u32 *num_sys_pages)
+{
+	int uars_per_sys_page;
+	int bfregs_per_sys_page;
+	int ref_bfregs = req->total_num_bfregs;
+
+	if (req->total_num_bfregs == 0)
+		return -EINVAL;
+
+	BUILD_BUG_ON(MLX5_MAX_BFREGS % MLX5_NON_FP_BFREGS_IN_PAGE);
+	BUILD_BUG_ON(MLX5_MAX_BFREGS < MLX5_NON_FP_BFREGS_IN_PAGE);
+
+	if (req->total_num_bfregs > MLX5_MAX_BFREGS)
+		return -ENOMEM;
+
+	uars_per_sys_page = get_uars_per_sys_page(dev, lib_uar_4k);
+	bfregs_per_sys_page = uars_per_sys_page * MLX5_NON_FP_BFREGS_PER_UAR;
+	req->total_num_bfregs = ALIGN(req->total_num_bfregs, bfregs_per_sys_page);
+	*num_sys_pages = req->total_num_bfregs / bfregs_per_sys_page;
+
+	if (req->num_low_latency_bfregs > req->total_num_bfregs - 1)
+		return -EINVAL;
+
+	mlx5_ib_dbg(dev, "uar_4k: fw support %s, lib support %s, user requested %d bfregs, alloated %d, using %d sys pages\n",
+		    MLX5_CAP_GEN(dev->mdev, uar_4k) ? "yes" : "no",
+		    lib_uar_4k ? "yes" : "no", ref_bfregs,
+		    req->total_num_bfregs, *num_sys_pages);
+
+	return 0;
+}
+
+static int allocate_uars(struct mlx5_ib_dev *dev, struct mlx5_ib_ucontext *context)
+{
+	struct mlx5_bfreg_info *bfregi;
+	int err;
+	int i;
+
+	bfregi = &context->bfregi;
+	for (i = 0; i < bfregi->num_sys_pages; i++) {
+		err = mlx5_cmd_alloc_uar(dev->mdev, &bfregi->sys_pages[i]);
+		if (err)
+			goto error;
+
+		mlx5_ib_dbg(dev, "allocated uar %d\n", bfregi->sys_pages[i]);
+	}
+	return 0;
+
+error:
+	for (--i; i >= 0; i--)
+		if (mlx5_cmd_free_uar(dev->mdev, bfregi->sys_pages[i]))
+			mlx5_ib_warn(dev, "failed to free uar %d\n", i);
+
+	return err;
+}
+
+static int deallocate_uars(struct mlx5_ib_dev *dev, struct mlx5_ib_ucontext *context)
+{
+	struct mlx5_bfreg_info *bfregi;
+	int err;
+	int i;
+
+	bfregi = &context->bfregi;
+	for (i = 0; i < bfregi->num_sys_pages; i++) {
+		err = mlx5_cmd_free_uar(dev->mdev, bfregi->sys_pages[i]);
+		if (err) {
+			mlx5_ib_warn(dev, "failed to free uar %d\n", i);
+			return err;
+		}
+	}
+	return 0;
+}
+
 static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 						  struct ib_udata *udata)
 {
@@ -1000,16 +1074,12 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 	struct mlx5_ib_alloc_ucontext_resp resp = {};
 	struct mlx5_ib_ucontext *context;
 	struct mlx5_bfreg_info *bfregi;
-	struct mlx5_uar *uars;
-	int gross_bfregs;
-	int num_uars;
 	int ver;
-	int bfregn;
 	int err;
-	int i;
 	size_t reqlen;
 	size_t min_req_v2 = offsetof(struct mlx5_ib_alloc_ucontext_req_v2,
 				     max_cqe_version);
+	bool lib_uar_4k;
 
 	if (!dev->ib_active)
 		return ERR_PTR(-EAGAIN);
@@ -1032,27 +1102,14 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 	if (req.flags)
 		return ERR_PTR(-EINVAL);
 
-	if (req.total_num_bfregs > MLX5_MAX_BFREGS)
-		return ERR_PTR(-ENOMEM);
-
-	if (req.total_num_bfregs == 0)
-		return ERR_PTR(-EINVAL);
-
 	if (req.comp_mask || req.reserved0 || req.reserved1 || req.reserved2)
 		return ERR_PTR(-EOPNOTSUPP);
 
-	if (reqlen > sizeof(req) &&
-	    !ib_is_udata_cleared(udata, sizeof(req),
-				 reqlen - sizeof(req)))
-		return ERR_PTR(-EOPNOTSUPP);
-
 	req.total_num_bfregs = ALIGN(req.total_num_bfregs,
 				    MLX5_NON_FP_BFREGS_PER_UAR);
 	if (req.num_low_latency_bfregs > req.total_num_bfregs - 1)
 		return ERR_PTR(-EINVAL);
 
-	num_uars = req.total_num_bfregs / MLX5_NON_FP_BFREGS_PER_UAR;
-	gross_bfregs = num_uars * MLX5_BFREGS_PER_UAR;
 	resp.qp_tab_size = 1 << MLX5_CAP_GEN(dev->mdev, log_max_qp);
 	if (mlx5_core_is_pf(dev->mdev) && MLX5_CAP_GEN(dev->mdev, bf))
 		resp.bf_reg_size = 1 << MLX5_CAP_GEN(dev->mdev, log_bf_reg_size);
@@ -1072,42 +1129,34 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 	if (!context)
 		return ERR_PTR(-ENOMEM);
 
+	lib_uar_4k = false;
 	bfregi = &context->bfregi;
-	mutex_init(&bfregi->lock);
-	uars = kcalloc(num_uars, sizeof(*uars), GFP_KERNEL);
-	if (!uars) {
-		err = -ENOMEM;
+
+	/* updates req->total_num_bfregs */
+	err = calc_total_bfregs(dev, lib_uar_4k, &req, &bfregi->num_sys_pages);
+	if (err)
 		goto out_ctx;
-	}
 
-	bfregi->bitmap = kcalloc(BITS_TO_LONGS(gross_bfregs),
-				sizeof(*bfregi->bitmap),
+	mutex_init(&bfregi->lock);
+	bfregi->lib_uar_4k = lib_uar_4k;
+	bfregi->count = kcalloc(req.total_num_bfregs, sizeof(*bfregi->count),
 				GFP_KERNEL);
-	if (!bfregi->bitmap) {
+	if (!bfregi->count) {
 		err = -ENOMEM;
-		goto out_uar_ctx;
-	}
-	/*
-	 * clear all fast path bfregs
-	 */
-	for (i = 0; i < gross_bfregs; i++) {
-		bfregn = i & 3;
-		if (bfregn == 2 || bfregn == 3)
-			set_bit(i, bfregi->bitmap);
+		goto out_ctx;
 	}
 
-	bfregi->count = kcalloc(gross_bfregs,
-				sizeof(*bfregi->count), GFP_KERNEL);
-	if (!bfregi->count) {
+	bfregi->sys_pages = kcalloc(bfregi->num_sys_pages,
+				    sizeof(*bfregi->sys_pages),
+				    GFP_KERNEL);
+	if (!bfregi->sys_pages) {
 		err = -ENOMEM;
-		goto out_bitmap;
+		goto out_count;
 	}
 
-	for (i = 0; i < num_uars; i++) {
-		err = mlx5_cmd_alloc_uar(dev->mdev, &uars[i].index);
-		if (err)
-			goto out_count;
-	}
+	err = allocate_uars(dev, context);
+	if (err)
+		goto out_sys_pages;
 
 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
 	context->ibucontext.invalidate_range = &mlx5_ib_invalidate_range;
@@ -1166,9 +1215,8 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 
 	bfregi->ver = ver;
 	bfregi->num_low_latency_bfregs = req.num_low_latency_bfregs;
-	bfregi->uars = uars;
-	bfregi->num_uars = num_uars;
 	context->cqe_version = resp.cqe_version;
+	context->lib_caps = false;
 
 	return &context->ibucontext;
 
@@ -1180,51 +1228,49 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
 	free_page(context->upd_xlt_page);
 
 out_uars:
-	for (i--; i >= 0; i--)
-		mlx5_cmd_free_uar(dev->mdev, uars[i].index);
-out_count:
-	kfree(bfregi->count);
+	deallocate_uars(dev, context);
 
-out_bitmap:
-	kfree(bfregi->bitmap);
+out_sys_pages:
+	kfree(bfregi->sys_pages);
 
-out_uar_ctx:
-	kfree(uars);
+out_count:
+	kfree(bfregi->count);
 
 out_ctx:
 	kfree(context);
+
 	return ERR_PTR(err);
 }
 
 static int mlx5_ib_dealloc_ucontext(struct ib_ucontext *ibcontext)
 {
 	struct mlx5_ib_ucontext *context = to_mucontext(ibcontext);
 	struct mlx5_ib_dev *dev = to_mdev(ibcontext->device);
-	struct mlx5_bfreg_info *bfregi = &context->bfregi;
-	int i;
+	struct mlx5_bfreg_info *bfregi;
 
+	bfregi = &context->bfregi;
 	if (MLX5_CAP_GEN(dev->mdev, log_max_transport_domain))
 		mlx5_core_dealloc_transport_domain(dev->mdev, context->tdn);
 
 	free_page(context->upd_xlt_page);
-
-	for (i = 0; i < bfregi->num_uars; i++) {
-		if (mlx5_cmd_free_uar(dev->mdev, bfregi->uars[i].index))
-			mlx5_ib_warn(dev, "Failed to free UAR 0x%x\n",
-				     bfregi->uars[i].index);
-	}
-
+	deallocate_uars(dev, context);
+	kfree(bfregi->sys_pages);
 	kfree(bfregi->count);
-	kfree(bfregi->bitmap);
-	kfree(bfregi->uars);
 	kfree(context);
 
 	return 0;
 }
 
-static phys_addr_t uar_index2pfn(struct mlx5_ib_dev *dev, int index)
+static phys_addr_t uar_index2pfn(struct mlx5_ib_dev *dev,
+				 struct mlx5_bfreg_info *bfregi,
+				 int idx)
 {
-	return (pci_resource_start(dev->mdev->pdev, 0) >> PAGE_SHIFT) + index;
+	int fw_uars_per_page;
+
+	fw_uars_per_page = MLX5_CAP_GEN(dev->mdev, uar_4k) ? MLX5_UARS_IN_PAGE : 1;
+
+	return (pci_resource_start(dev->mdev->pdev, 0) >> PAGE_SHIFT) +
+			bfregi->sys_pages[idx] / fw_uars_per_page;
 }
 
 static int get_command(unsigned long offset)
@@ -1384,6 +1430,18 @@ static int uar_mmap(struct mlx5_ib_dev *dev, enum mlx5_ib_mmap_cmd cmd,
 	unsigned long idx;
 	phys_addr_t pfn, pa;
 	pgprot_t prot;
+	int uars_per_page;
+
+	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
+		return -EINVAL;
+
+	uars_per_page = get_uars_per_sys_page(dev, bfregi->lib_uar_4k);
+	idx = get_index(vma->vm_pgoff);
+	if (idx % uars_per_page ||
+	    idx * uars_per_page >= bfregi->num_sys_pages) {
+		mlx5_ib_warn(dev, "invalid uar index %lu\n", idx);
+		return -EINVAL;
+	}
 
 	switch (cmd) {
 	case MLX5_IB_MMAP_WC_PAGE:
@@ -1406,14 +1464,7 @@ static int uar_mmap(struct mlx5_ib_dev *dev, enum mlx5_ib_mmap_cmd cmd,
 		return -EINVAL;
 	}
 
-	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
-		return -EINVAL;
-
-	idx = get_index(vma->vm_pgoff);
-	if (idx >= bfregi->num_uars)
-		return -EINVAL;
-
-	pfn = uar_index2pfn(dev, bfregi->uars[idx].index);
+	pfn = uar_index2pfn(dev, bfregi, idx);
 	mlx5_ib_dbg(dev, "uar idx 0x%lx, pfn %pa\n", idx, &pfn);
 
 	vma->vm_page_prot = prot;

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -90,7 +90,6 @@ enum mlx5_ib_latency_class {
 	MLX5_IB_LATENCY_CLASS_LOW,
 	MLX5_IB_LATENCY_CLASS_MEDIUM,
 	MLX5_IB_LATENCY_CLASS_HIGH,
-	MLX5_IB_LATENCY_CLASS_FAST_PATH
 };
 
 enum mlx5_ib_mad_ifc_flags {
@@ -129,6 +128,7 @@ struct mlx5_ib_ucontext {
 	unsigned long		upd_xlt_page;
 	/* protect ODP/KSM */
 	struct mutex		upd_xlt_page_mutex;
+	u64			lib_caps;
 };
 
 static inline struct mlx5_ib_ucontext *to_mucontext(struct ib_ucontext *ibucontext)
@@ -975,4 +975,17 @@ static inline int get_srq_user_index(struct mlx5_ib_ucontext *ucontext,
 
 	return verify_assign_uidx(cqe_version, ucmd->uidx, user_index);
 }
+
+static inline int get_uars_per_sys_page(struct mlx5_ib_dev *dev, bool lib_support)
+{
+	return lib_support && MLX5_CAP_GEN(dev->mdev, uar_4k) ?
+				MLX5_UARS_IN_PAGE : 1;
+}
+
+static inline int get_num_uars(struct mlx5_ib_dev *dev,
+			       struct mlx5_bfreg_info *bfregi)
+{
+	return get_uars_per_sys_page(dev, bfregi->lib_uar_4k) * bfregi->num_sys_pages;
+}
+
 #endif /* MLX5_IB_H */