RE: [Patch v7 12/12] RDMA/mana_ib: Add a driver for Microsoft Azure Network Adapter

[Long Li]

> Subject: Re: [Patch v7 12/12] RDMA/mana_ib: Add a driver for Microsoft
> Azure Network Adapter
> 
> On Mon, 2022-10-17 at 12:20 -0700, longli@xxxxxxxxxxxxxxxxx wrote:
> > diff --git a/drivers/infiniband/hw/mana/main.c
> > b/drivers/infiniband/hw/mana/main.c
> > new file mode 100644
> > index 000000000000..57e5f9dca454
> > --- /dev/null
> > +++ b/drivers/infiniband/hw/mana/main.c
> 
> [...]
> 
> > +static int mana_gd_destroy_doorbell_page(struct gdma_context *gc,
> > +					 int doorbell_page)
> > +{
> > +	struct gdma_destroy_resource_range_req req = {};
> > +	struct gdma_resp_hdr resp = {};
> > +	int err;
> > +
> > +	mana_gd_init_req_hdr(&req.hdr,
> GDMA_DESTROY_RESOURCE_RANGE,
> > +			     sizeof(req), sizeof(resp));
> > +
> > +	req.resource_type = GDMA_RESOURCE_DOORBELL_PAGE;
> > +	req.num_resources = 1;
> > +	req.allocated_resources = doorbell_page;
> > +
> > +	err = mana_gd_send_request(gc, sizeof(req), &req, sizeof(resp),
> &resp);
> > +	if (err || resp.status) {
> > +		dev_err(gc->dev,
> > +			"Failed to destroy doorbell page: ret %d, 0x%x\n",
> > +			err, resp.status);
> > +		return err ? err : -EPROTO;
> 
> Minor nit: the preferred style is:
> 		return err ?: -EPROTO;
> 
> a few other occurences below.

Will change this.

> 
> > +	}
> > +
> > +	return 0;
> > +}
> 
> [...]
> 
> > +int mana_ib_gd_create_dma_region(struct mana_ib_dev *dev, struct
> ib_umem *umem,
> > +				 mana_handle_t *gdma_region)
> > +{
> > +	struct gdma_dma_region_add_pages_req *add_req = NULL;
> > +	struct gdma_create_dma_region_resp create_resp = {};
> > +	struct gdma_create_dma_region_req *create_req;
> > +	size_t num_pages_cur, num_pages_to_handle;
> > +	unsigned int create_req_msg_size;
> > +	struct hw_channel_context *hwc;
> > +	struct ib_block_iter biter;
> > +	size_t max_pgs_create_cmd;
> > +	struct gdma_context *gc;
> > +	size_t num_pages_total;
> > +	struct gdma_dev *mdev;
> > +	unsigned long page_sz;
> > +	void *request_buf;
> > +	unsigned int i;
> > +	int err;
> > +
> > +	mdev = dev->gdma_dev;
> > +	gc = mdev->gdma_context;
> > +	hwc = gc->hwc.driver_data;
> > +
> > +	/* Hardware requires dma region to align to chosen page size */
> > +	page_sz = ib_umem_find_best_pgsz(umem, PAGE_SZ_BM, 0);
> > +	if (!page_sz) {
> > +		ibdev_dbg(&dev->ib_dev, "failed to find page size.\n");
> > +		return -ENOMEM;
> > +	}
> > +	num_pages_total = ib_umem_num_dma_blocks(umem, page_sz);
> > +
> > +	max_pgs_create_cmd =
> > +		(hwc->max_req_msg_size - sizeof(*create_req)) /
> sizeof(u64);
> > +	num_pages_to_handle =
> > +		min_t(size_t, num_pages_total, max_pgs_create_cmd);
> > +	create_req_msg_size =
> > +		struct_size(create_req, page_addr_list,
> num_pages_to_handle);
> > +
> > +	request_buf = kzalloc(hwc->max_req_msg_size, GFP_KERNEL);
> > +	if (!request_buf)
> > +		return -ENOMEM;
> > +
> > +	create_req = request_buf;
> > +	mana_gd_init_req_hdr(&create_req->hdr,
> GDMA_CREATE_DMA_REGION,
> > +			     create_req_msg_size, sizeof(create_resp));
> > +
> > +	create_req->length = umem->length;
> > +	create_req->offset_in_page = umem->address & (page_sz - 1);
> > +	create_req->gdma_page_type = order_base_2(page_sz) -
> PAGE_SHIFT;
> > +	create_req->page_count = num_pages_total;
> > +	create_req->page_addr_list_len = num_pages_to_handle;
> > +
> > +	ibdev_dbg(&dev->ib_dev, "size_dma_region %lu
> num_pages_total %lu\n",
> > +		  umem->length, num_pages_total);
> > +
> > +	ibdev_dbg(&dev->ib_dev, "page_sz %lu offset_in_page %u\n",
> > +		  page_sz, create_req->offset_in_page);
> > +
> > +	ibdev_dbg(&dev->ib_dev, "num_pages_to_handle %lu,
> gdma_page_type %u",
> > +		  num_pages_to_handle, create_req->gdma_page_type);
> > +
> > +	__rdma_umem_block_iter_start(&biter, umem, page_sz);
> > +
> > +	for (i = 0; i < num_pages_to_handle; ++i) {
> > +		dma_addr_t cur_addr;
> > +
> > +		__rdma_block_iter_next(&biter);
> > +		cur_addr = rdma_block_iter_dma_address(&biter);
> > +
> > +		create_req->page_addr_list[i] = cur_addr;
> > +	}
> > +
> > +	err = mana_gd_send_request(gc, create_req_msg_size, create_req,
> > +				   sizeof(create_resp), &create_resp);
> > +	if (err || create_resp.hdr.status) {
> > +		ibdev_dbg(&dev->ib_dev,
> > +			  "Failed to create DMA region: %d, 0x%x\n", err,
> > +			  create_resp.hdr.status);
> > +		if (!err)
> > +			err = -EPROTO;
> > +
> > +		kfree(request_buf);
> > +		return err;
> 
> Minor nit: you can avoid a little code doplication replacing the above
> 2 lines with:
> 		goto out;

Good suggestion, will make the change.

> 
> and ...
> 
> > +	}
> > +
> > +	*gdma_region = create_resp.dma_region_handle;
> > +	ibdev_dbg(&dev->ib_dev, "Created DMA region with handle
> 0x%llx\n",
> > +		  *gdma_region);
> > +
> > +	num_pages_cur = num_pages_to_handle;
> > +
> > +	if (num_pages_cur < num_pages_total) {
> > +		unsigned int add_req_msg_size;
> > +		size_t max_pgs_add_cmd =
> > +			(hwc->max_req_msg_size - sizeof(*add_req)) /
> > +			sizeof(u64);
> > +
> > +		num_pages_to_handle =
> > +			min_t(size_t, num_pages_total - num_pages_cur,
> > +			      max_pgs_add_cmd);
> > +
> > +		/* Calculate the max num of pages that will be handled */
> > +		add_req_msg_size = struct_size(add_req, page_addr_list,
> > +					       num_pages_to_handle);
> > +		add_req = request_buf;
> > +
> > +		while (num_pages_cur < num_pages_total) {
> > +			struct gdma_general_resp add_resp = {};
> > +			u32 expected_status = 0;
> > +
> > +			if (num_pages_cur + num_pages_to_handle <
> > +			    num_pages_total) {
> > +				/* Status indicating more pages are needed
> */
> > +				expected_status =
> GDMA_STATUS_MORE_ENTRIES;
> > +			}
> > +
> > +			memset(add_req, 0, add_req_msg_size);
> > +
> > +			mana_gd_init_req_hdr(&add_req->hdr,
> > +
> GDMA_DMA_REGION_ADD_PAGES,
> > +					     add_req_msg_size,
> > +					     sizeof(add_resp));
> > +			add_req->dma_region_handle = *gdma_region;
> > +			add_req->page_addr_list_len =
> num_pages_to_handle;
> > +
> > +			for (i = 0; i < num_pages_to_handle; ++i) {
> > +				dma_addr_t cur_addr =
> > +
> 	rdma_block_iter_dma_address(&biter);
> > +				add_req->page_addr_list[i] = cur_addr;
> > +				__rdma_block_iter_next(&biter);
> > +
> > +				ibdev_dbg(&dev->ib_dev,
> > +					  "page_addr_list %lu addr 0x%llx\n",
> > +					  num_pages_cur + i, cur_addr);
> > +			}
> > +
> > +			err = mana_gd_send_request(gc, add_req_msg_size,
> > +						   add_req, sizeof(add_resp),
> > +						   &add_resp);
> > +			if (err || add_resp.hdr.status != expected_status) {
> > +				ibdev_dbg(&dev->ib_dev,
> > +					  "Failed put DMA
> pages %u: %d,0x%x\n",
> > +					  i, err, add_resp.hdr.status);
> > +				err = -EPROTO;
> > +				break;
> > +			}
> > +
> > +			num_pages_cur += num_pages_to_handle;
> > +			num_pages_to_handle =
> > +				min_t(size_t, num_pages_total -
> num_pages_cur,
> > +				      max_pgs_add_cmd);
> > +			add_req_msg_size = sizeof(*add_req) +
> > +					   num_pages_to_handle *
> sizeof(u64);
> > +		}
> > +	}
> > +
> > +	kfree(request_buf);
> > +
> > +	if (err)
> > +		mana_ib_gd_destroy_dma_region(dev,
> create_resp.dma_region_handle);
> 
> ... here:
> 
> 	if (err)
> 		mana_ib_gd_destroy_dma_region(dev,
> create_resp.dma_region_handle);
> 
> out:
> 	kfree(request_buf);
> 
> > +
> > +	return err;
> > +}
> 
> [...]
> 
> > diff --git a/drivers/infiniband/hw/mana/qp.c
> > b/drivers/infiniband/hw/mana/qp.c new file mode 100644 index
> > 000000000000..fec7d4a06ace
> > --- /dev/null
> > +++ b/drivers/infiniband/hw/mana/qp.c
> > @@ -0,0 +1,505 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Copyright (c) 2022, Microsoft Corporation. All rights reserved.
> > + */
> > +
> > +#include "mana_ib.h"
> > +
> > +static int mana_ib_cfg_vport_steering(struct mana_ib_dev *dev,
> > +				      struct net_device *ndev,
> > +				      mana_handle_t default_rxobj,
> > +				      mana_handle_t ind_table[],
> > +				      u32 log_ind_tbl_size, u32
> rx_hash_key_len,
> > +				      u8 *rx_hash_key)
> > +{
> > +	struct mana_port_context *mpc = netdev_priv(ndev);
> > +	struct mana_cfg_rx_steer_req *req = NULL;
> > +	struct mana_cfg_rx_steer_resp resp = {};
> > +	mana_handle_t *req_indir_tab;
> > +	struct gdma_context *gc;
> > +	struct gdma_dev *mdev;
> > +	u32 req_buf_size;
> > +	int i, err;
> > +
> > +	mdev = dev->gdma_dev;
> > +	gc = mdev->gdma_context;
> > +
> > +	req_buf_size =
> > +		sizeof(*req) + sizeof(mana_handle_t) *
> MANA_INDIRECT_TABLE_SIZE;
> > +	req = kzalloc(req_buf_size, GFP_KERNEL);
> > +	if (!req)
> > +		return -ENOMEM;
> > +
> > +	mana_gd_init_req_hdr(&req->hdr, MANA_CONFIG_VPORT_RX,
> req_buf_size,
> > +			     sizeof(resp));
> > +
> > +	req->vport = mpc->port_handle;
> > +	req->rx_enable = 1;
> > +	req->update_default_rxobj = 1;
> > +	req->default_rxobj = default_rxobj;
> > +	req->hdr.dev_id = mdev->dev_id;
> > +
> > +	/* If there are more than 1 entries in indirection table, enable RSS */
> > +	if (log_ind_tbl_size)
> > +		req->rss_enable = true;
> > +
> > +	req->num_indir_entries = MANA_INDIRECT_TABLE_SIZE;
> > +	req->indir_tab_offset = sizeof(*req);
> > +	req->update_indir_tab = true;
> > +
> > +	req_indir_tab = (mana_handle_t *)(req + 1);
> > +	/* The ind table passed to the hardware must have
> > +	 * MANA_INDIRECT_TABLE_SIZE entries. Adjust the verb
> > +	 * ind_table to MANA_INDIRECT_TABLE_SIZE if required
> > +	 */
> > +	ibdev_dbg(&dev->ib_dev, "ind table size %u\n", 1 <<
> log_ind_tbl_size);
> > +	for (i = 0; i < MANA_INDIRECT_TABLE_SIZE; i++) {
> > +		req_indir_tab[i] = ind_table[i % (1 << log_ind_tbl_size)];
> > +		ibdev_dbg(&dev->ib_dev, "index %u handle 0x%llx\n", i,
> > +			  req_indir_tab[i]);
> > +	}
> > +
> > +	req->update_hashkey = true;
> > +	if (rx_hash_key_len)
> > +		memcpy(req->hashkey, rx_hash_key, rx_hash_key_len);
> > +	else
> > +		netdev_rss_key_fill(req->hashkey, MANA_HASH_KEY_SIZE);
> > +
> > +	ibdev_dbg(&dev->ib_dev, "vport handle %llu default_rxobj
> 0x%llx\n",
> > +		  req->vport, default_rxobj);
> > +
> > +	err = mana_gd_send_request(gc, req_buf_size, req, sizeof(resp),
> &resp);
> > +	if (err) {
> > +		netdev_err(ndev, "Failed to configure vPort RX: %d\n", err);
> > +		goto out;
> > +	}
> > +
> > +	if (resp.hdr.status) {
> > +		netdev_err(ndev, "vPort RX configuration failed: 0x%x\n",
> > +			   resp.hdr.status);
> > +		err = -EPROTO;
> 
> This is confusing: if this error condition is reached, both error and succesful
> configuration will be logged. I guess an additional:
> 
> 		goto out;
> 
> is needed.

Yes, it's confusing. Will change this.

> 
> > +	}
> > +
> > +	netdev_info(ndev, "Configured steering vPort %llu
> log_entries %u\n",
> > +		    mpc->port_handle, log_ind_tbl_size);
> > +
> > +out:
> > +	kfree(req);
> > +	return err;
> > +}
> > +
> > +static int mana_ib_create_qp_rss(struct ib_qp *ibqp, struct ib_pd *pd,
> > +				 struct ib_qp_init_attr *attr,
> > +				 struct ib_udata *udata)
> > +{
> > +	struct mana_ib_qp *qp = container_of(ibqp, struct mana_ib_qp,
> ibqp);
> > +	struct mana_ib_dev *mdev =
> > +		container_of(pd->device, struct mana_ib_dev, ib_dev);
> > +	struct ib_rwq_ind_table *ind_tbl = attr->rwq_ind_tbl;
> > +	struct mana_ib_create_qp_rss_resp resp = {};
> > +	struct mana_ib_create_qp_rss ucmd = {};
> > +	struct gdma_dev *gd = mdev->gdma_dev;
> > +	mana_handle_t *mana_ind_table;
> > +	struct mana_port_context *mpc;
> > +	struct mana_context *mc;
> > +	struct net_device *ndev;
> > +	struct mana_ib_cq *cq;
> > +	struct mana_ib_wq *wq;
> > +	unsigned int ind_tbl_size;
> > +	struct ib_cq *ibcq;
> > +	struct ib_wq *ibwq;
> > +	u32 port;
> > +	int ret;
> > +	int i;
> 
> This causes a build warning with clang:
> 
> ../drivers/infiniband/hw/mana/qp.c:172:6: warning: variable 'i' is used
> uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
>         if (!mana_ind_table) {
>             ^~~~~~~~~~~~~~~
> ../drivers/infiniband/hw/mana/qp.c:241:9: note: uninitialized use occurs
> here
>         while (i-- > 0) {
>                ^
> ../drivers/infiniband/hw/mana/qp.c:172:2: note: remove the 'if' if its
> condition is always false
>         if (!mana_ind_table) {
>         ^~~~~~~~~~~~~~~~~~~~~~
> ../drivers/infiniband/hw/mana/qp.c:113:7: note: initialize the variable 'i' to
> silence this warning
>         int i;

Thank you. Will fix it.

> 
> 
> 
> > +
> > +	mc = gd->driver_data;
> > +
> > +	if (!udata || udata->inlen < sizeof(ucmd))
> > +		return -EINVAL;
> > +
> > +	ret = ib_copy_from_udata(&ucmd, udata, min(sizeof(ucmd), udata-
> >inlen));
> > +	if (ret) {
> > +		ibdev_dbg(&mdev->ib_dev,
> > +			  "Failed copy from udata for create rss-qp, err %d\n",
> > +			  ret);
> > +		return -EFAULT;
> > +	}
> > +
> > +	if (attr->cap.max_recv_wr > MAX_SEND_BUFFERS_PER_QUEUE) {
> > +		ibdev_dbg(&mdev->ib_dev,
> > +			  "Requested max_recv_wr %d exceeding limit\n",
> > +			  attr->cap.max_recv_wr);
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (attr->cap.max_recv_sge > MAX_RX_WQE_SGL_ENTRIES) {
> > +		ibdev_dbg(&mdev->ib_dev,
> > +			  "Requested max_recv_sge %d exceeding limit\n",
> > +			  attr->cap.max_recv_sge);
> > +		return -EINVAL;
> > +	}
> > +
> > +	ind_tbl_size = 1 << ind_tbl->log_ind_tbl_size;
> > +	if (ind_tbl_size > MANA_INDIRECT_TABLE_SIZE) {
> > +		ibdev_dbg(&mdev->ib_dev,
> > +			  "Indirect table size %d exceeding limit\n",
> > +			  ind_tbl_size);
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (ucmd.rx_hash_function != MANA_IB_RX_HASH_FUNC_TOEPLITZ)
> {
> > +		ibdev_dbg(&mdev->ib_dev,
> > +			  "RX Hash function is not supported, %d\n",
> > +			  ucmd.rx_hash_function);
> > +		return -EINVAL;
> > +	}
> > +
> > +	/* IB ports start with 1, MANA start with 0 */
> > +	port = ucmd.port;
> > +	if (port < 1 || port > mc->num_ports) {
> > +		ibdev_dbg(&mdev->ib_dev, "Invalid port %u in creating
> qp\n",
> > +			  port);
> > +		return -EINVAL;
> > +	}
> > +	ndev = mc->ports[port - 1];
> > +	mpc = netdev_priv(ndev);
> > +
> > +	ibdev_dbg(&mdev->ib_dev, "rx_hash_function %d port %d\n",
> > +		  ucmd.rx_hash_function, port);
> > +
> > +	mana_ind_table = kcalloc(ind_tbl_size, sizeof(mana_handle_t),
> > +				 GFP_KERNEL);
> > +	if (!mana_ind_table) {
> > +		ret = -ENOMEM;
> > +		goto fail;
> > +	}
> > +
> > +	qp->port = port;
> > +
> > +	for (i = 0; i < ind_tbl_size; i++) {
> > +		struct mana_obj_spec wq_spec = {};
> > +		struct mana_obj_spec cq_spec = {};
> > +
> > +		ibwq = ind_tbl->ind_tbl[i];
> > +		wq = container_of(ibwq, struct mana_ib_wq, ibwq);
> > +
> > +		ibcq = ibwq->cq;
> > +		cq = container_of(ibcq, struct mana_ib_cq, ibcq);
> > +
> > +		wq_spec.gdma_region = wq->gdma_region;
> > +		wq_spec.queue_size = wq->wq_buf_size;
> > +
> > +		cq_spec.gdma_region = cq->gdma_region;
> > +		cq_spec.queue_size = cq->cqe * COMP_ENTRY_SIZE;
> > +		cq_spec.modr_ctx_id = 0;
> > +		cq_spec.attached_eq = GDMA_CQ_NO_EQ;
> > +
> > +		ret = mana_create_wq_obj(mpc, mpc->port_handle,
> GDMA_RQ,
> > +					 &wq_spec, &cq_spec, &wq-
> >rx_object);
> > +		if (ret)
> > +			goto fail;
> > +
> > +		/* The GDMA regions are now owned by the WQ object */
> > +		wq->gdma_region = GDMA_INVALID_DMA_REGION;
> > +		cq->gdma_region = GDMA_INVALID_DMA_REGION;
> > +
> > +		wq->id = wq_spec.queue_index;
> > +		cq->id = cq_spec.queue_index;
> > +
> > +		ibdev_dbg(&mdev->ib_dev,
> > +			  "ret %d rx_object 0x%llx wq id %llu cq id %llu\n",
> > +			  ret, wq->rx_object, wq->id, cq->id);
> > +
> > +		resp.entries[i].cqid = cq->id;
> > +		resp.entries[i].wqid = wq->id;
> > +
> > +		mana_ind_table[i] = wq->rx_object;
> > +	}
> > +	resp.num_entries = i;
> > +
> > +	ret = mana_ib_cfg_vport_steering(mdev, ndev, wq->rx_object,
> > +					 mana_ind_table,
> > +					 ind_tbl->log_ind_tbl_size,
> > +					 ucmd.rx_hash_key_len,
> > +					 ucmd.rx_hash_key);
> > +	if (ret)
> > +		goto fail;
> > +
> > +	ret = ib_copy_to_udata(udata, &resp, sizeof(resp));
> > +	if (ret) {
> > +		ibdev_dbg(&mdev->ib_dev,
> > +			  "Failed to copy to udata create rss-qp, %d\n",
> > +			  ret);
> > +		goto fail;
> > +	}
> > +
> > +	kfree(mana_ind_table);
> > +
> > +	return 0;
> > +
> > +fail:
> > +	while (i-- > 0) {
> > +		ibwq = ind_tbl->ind_tbl[i];
> > +		wq = container_of(ibwq, struct mana_ib_wq, ibwq);
> > +		mana_destroy_wq_obj(mpc, GDMA_RQ, wq->rx_object);
> > +	}
> > +
> > +	kfree(mana_ind_table);
> > +
> > +	return ret;
> > +}
> 
> 
> Cheers,
> 
> Paolo