Re: [PATCH rdma-core 1/5] verbs: Support dma-buf based memory region

Yishai Hadas <yishaih@xxxxxxxxxx> · Tue, 24 Nov 2020 12:31:46 +0200

On 11/23/2020 7:53 PM, Jianxin Xiong wrote:
Add new API function and new provider method for registering dma-buf
based memory region. Update the man page and bump the API version.

Signed-off-by: Jianxin Xiong <jianxin.xiong@xxxxxxxxx>
---
  kernel-headers/rdma/ib_user_ioctl_cmds.h | 14 ++++++++++++
  libibverbs/cmd_mr.c                      | 38 ++++++++++++++++++++++++++++++++
  libibverbs/driver.h                      |  7 ++++++
  libibverbs/dummy_ops.c                   | 11 +++++++++
  libibverbs/libibverbs.map.in             |  6 +++++
  libibverbs/man/ibv_reg_mr.3              | 21 ++++++++++++++++--
  libibverbs/verbs.c                       | 19 ++++++++++++++++
  libibverbs/verbs.h                       | 10 +++++++++
  8 files changed, 124 insertions(+), 2 deletions(-)

diff --git a/kernel-headers/rdma/ib_user_ioctl_cmds.h b/kernel-headers/rdma/ib_user_ioctl_cmds.h
index 7968a18..dafc7eb 100644
--- a/kernel-headers/rdma/ib_user_ioctl_cmds.h
+++ b/kernel-headers/rdma/ib_user_ioctl_cmds.h
@@ -1,5 +1,6 @@
  /*
   * Copyright (c) 2018, Mellanox Technologies inc.  All rights reserved.
+ * Copyright (c) 2020, Intel Corporation. All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
@@ -251,6 +252,7 @@ enum uverbs_methods_mr {
  	UVERBS_METHOD_MR_DESTROY,
  	UVERBS_METHOD_ADVISE_MR,
  	UVERBS_METHOD_QUERY_MR,
+	UVERBS_METHOD_REG_DMABUF_MR,
  };
  
  enum uverbs_attrs_mr_destroy_ids {
@@ -272,6 +274,18 @@ enum uverbs_attrs_query_mr_cmd_attr_ids {
  	UVERBS_ATTR_QUERY_MR_RESP_IOVA,
  };
  
+enum uverbs_attrs_reg_dmabuf_mr_cmd_attr_ids {
+	UVERBS_ATTR_REG_DMABUF_MR_HANDLE,
+	UVERBS_ATTR_REG_DMABUF_MR_PD_HANDLE,
+	UVERBS_ATTR_REG_DMABUF_MR_OFFSET,
+	UVERBS_ATTR_REG_DMABUF_MR_LENGTH,
+	UVERBS_ATTR_REG_DMABUF_MR_IOVA,
+	UVERBS_ATTR_REG_DMABUF_MR_FD,
+	UVERBS_ATTR_REG_DMABUF_MR_ACCESS_FLAGS,
+	UVERBS_ATTR_REG_DMABUF_MR_RESP_LKEY,
+	UVERBS_ATTR_REG_DMABUF_MR_RESP_RKEY,
+};
+
  enum uverbs_attrs_create_counters_cmd_attr_ids {
  	UVERBS_ATTR_CREATE_COUNTERS_HANDLE,
  };
diff --git a/libibverbs/cmd_mr.c b/libibverbs/cmd_mr.c
index 42dbe42..91ce2ef 100644
--- a/libibverbs/cmd_mr.c
+++ b/libibverbs/cmd_mr.c
@@ -1,5 +1,6 @@
  /*
   * Copyright (c) 2018 Mellanox Technologies, Ltd.  All rights reserved.
+ * Copyright (c) 2020 Intel Corporation.  All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
@@ -116,3 +117,40 @@ int ibv_cmd_query_mr(struct ibv_pd *pd, struct verbs_mr *vmr,
  	return 0;
  }
  
+int ibv_cmd_reg_dmabuf_mr(struct ibv_pd *pd, uint64_t offset, size_t length,
+			  uint64_t iova, int fd, int access,
+			  struct verbs_mr *vmr)
+{
+	DECLARE_COMMAND_BUFFER(cmdb, UVERBS_OBJECT_MR,
+			       UVERBS_METHOD_REG_DMABUF_MR,
+			       9);
+	struct ib_uverbs_attr *handle;
+	uint32_t lkey, rkey;
+	int ret;
+
+	handle = fill_attr_out_obj(cmdb, UVERBS_ATTR_REG_DMABUF_MR_HANDLE);
+	fill_attr_out_ptr(cmdb, UVERBS_ATTR_REG_DMABUF_MR_RESP_LKEY, &lkey);
+	fill_attr_out_ptr(cmdb, UVERBS_ATTR_REG_DMABUF_MR_RESP_RKEY, &rkey);
+
+	fill_attr_in_obj(cmdb, UVERBS_ATTR_REG_DMABUF_MR_PD_HANDLE, pd->handle);
+	fill_attr_in_uint64(cmdb, UVERBS_ATTR_REG_DMABUF_MR_OFFSET, offset);
+	fill_attr_in_uint64(cmdb, UVERBS_ATTR_REG_DMABUF_MR_LENGTH, length);
+	fill_attr_in_uint64(cmdb, UVERBS_ATTR_REG_DMABUF_MR_IOVA, iova);
+	fill_attr_in_uint32(cmdb, UVERBS_ATTR_REG_DMABUF_MR_FD, fd);
+	fill_attr_in_uint32(cmdb, UVERBS_ATTR_REG_DMABUF_MR_ACCESS_FLAGS, access);
+
+	ret = execute_ioctl(pd->context, cmdb);
+	if (ret)
+		return errno;
+
+	vmr->ibv_mr.handle =
+		read_attr_obj(UVERBS_ATTR_REG_DMABUF_MR_HANDLE, handle);
+	vmr->ibv_mr.context = pd->context;
+	vmr->ibv_mr.lkey    = lkey;
+	vmr->ibv_mr.rkey    = rkey;
+	vmr->ibv_mr.pd	    = pd;
+	vmr->ibv_mr.addr    = (void *)offset;
+	vmr->ibv_mr.length  = length;
+	vmr->mr_type        = IBV_MR_TYPE_MR;
+	return 0;
+}
diff --git a/libibverbs/driver.h b/libibverbs/driver.h
index ab80f4b..d6a9d0a 100644
--- a/libibverbs/driver.h
+++ b/libibverbs/driver.h
@@ -2,6 +2,7 @@
   * Copyright (c) 2004, 2005 Topspin Communications.  All rights reserved.
   * Copyright (c) 2005, 2006 Cisco Systems, Inc.  All rights reserved.
   * Copyright (c) 2005 PathScale, Inc.  All rights reserved.
+ * Copyright (c) 2020 Intel Corporation. All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
@@ -373,6 +374,9 @@ struct verbs_context_ops {
  	struct ibv_mr *(*reg_dm_mr)(struct ibv_pd *pd, struct ibv_dm *dm,
  				    uint64_t dm_offset, size_t length,
  				    unsigned int access);
+	struct ibv_mr *(*reg_dmabuf_mr)(struct ibv_pd *pd, uint64_t offset,
+					size_t length, uint64_t iova,
+					int fd, int access);
  	struct ibv_mr *(*reg_mr)(struct ibv_pd *pd, void *addr, size_t length,
  				 uint64_t hca_va, int access);
  	int (*req_notify_cq)(struct ibv_cq *cq, int solicited_only);
@@ -498,6 +502,9 @@ int ibv_cmd_advise_mr(struct ibv_pd *pd,
  		      uint32_t flags,
  		      struct ibv_sge *sg_list,
  		      uint32_t num_sge);
+int ibv_cmd_reg_dmabuf_mr(struct ibv_pd *pd, uint64_t offset, size_t length,
+			  uint64_t iova, int fd, int access,
+			  struct verbs_mr *vmr);
  int ibv_cmd_alloc_mw(struct ibv_pd *pd, enum ibv_mw_type type,
  		     struct ibv_mw *mw, struct ibv_alloc_mw *cmd,
  		     size_t cmd_size,
diff --git a/libibverbs/dummy_ops.c b/libibverbs/dummy_ops.c
index e5af9e4..dca96d2 100644
--- a/libibverbs/dummy_ops.c
+++ b/libibverbs/dummy_ops.c
@@ -1,5 +1,6 @@
  /*
   * Copyright (c) 2017 Mellanox Technologies, Inc.  All rights reserved.
+ * Copyright (c) 2020 Intel Corporation.  All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
@@ -452,6 +453,14 @@ static struct ibv_mr *reg_mr(struct ibv_pd *pd, void *addr, size_t length,
  	return NULL;
  }
  
+static struct ibv_mr *reg_dmabuf_mr(struct ibv_pd *pd, uint64_t offset,
+				    size_t length, uint64_t iova,
+				    int fd, int access)
+{
+	errno = ENOSYS;
+	return NULL;
+}
+
  static int req_notify_cq(struct ibv_cq *cq, int solicited_only)
  {
  	return EOPNOTSUPP;
@@ -560,6 +569,7 @@ const struct verbs_context_ops verbs_dummy_ops = {
  	query_srq,
  	read_counters,
  	reg_dm_mr,
+	reg_dmabuf_mr,
  	reg_mr,
  	req_notify_cq,
  	rereg_mr,
@@ -689,6 +699,7 @@ void verbs_set_ops(struct verbs_context *vctx,
  	SET_PRIV_OP_IC(vctx, set_ece);
  	SET_PRIV_OP_IC(vctx, unimport_mr);
  	SET_PRIV_OP_IC(vctx, unimport_pd);
+	SET_OP(vctx, reg_dmabuf_mr);
  
  #undef SET_OP
  #undef SET_OP2
diff --git a/libibverbs/libibverbs.map.in b/libibverbs/libibverbs.map.in
index b5ccaca..f67e1ef 100644
--- a/libibverbs/libibverbs.map.in
+++ b/libibverbs/libibverbs.map.in
@@ -148,6 +148,11 @@ IBVERBS_1.11 {
  		_ibv_query_gid_table;
  } IBVERBS_1.10;
  
+IBVERBS_1.12 {
+	global:
+		ibv_reg_dmabuf_mr;
+} IBVERBS_1.11;
+
  /* If any symbols in this stanza change ABI then the entire staza gets a new symbol
     version. See the top level CMakeLists.txt for this setting. */
  
@@ -211,6 +216,7 @@ IBVERBS_PRIVATE_@IBVERBS_PABI_VERSION@ {
  		ibv_cmd_query_srq;
  		ibv_cmd_read_counters;
  		ibv_cmd_reg_dm_mr;
+		ibv_cmd_reg_dmabuf_mr;
  		ibv_cmd_reg_mr;
  		ibv_cmd_req_notify_cq;
  		ibv_cmd_rereg_mr;
diff --git a/libibverbs/man/ibv_reg_mr.3 b/libibverbs/man/ibv_reg_mr.3
index 2bfc955..4975c79 100644
--- a/libibverbs/man/ibv_reg_mr.3
+++ b/libibverbs/man/ibv_reg_mr.3
@@ -3,7 +3,7 @@
  .\"
  .TH IBV_REG_MR 3 2006-10-31 libibverbs "Libibverbs Programmer's Manual"
  .SH "NAME"
-ibv_reg_mr, ibv_reg_mr_iova, ibv_dereg_mr \- register or deregister a memory region (MR)
+ibv_reg_mr, ibv_reg_mr_iova, ibv_reg_dmabuf_mr, ibv_dereg_mr \- register or deregister a memory region (MR)
  .SH "SYNOPSIS"
  .nf
  .B #include <infiniband/verbs.h>
@@ -15,6 +15,9 @@ ibv_reg_mr, ibv_reg_mr_iova, ibv_dereg_mr \- register or deregister a memory reg
  .BI "                               size_t " "length" ", uint64_t " "hca_va" ,
  .BI "                               int " "access" );
  .sp
+.BI "struct ibv_mr *ibv_reg_dmabuf_mr(struct ibv_pd " "*pd" ", uint64_t " "offset" ,
+.BI "                                 size_t " "length" ", int " "access" );
+.sp


This misses the 'fd' parameter.

  .BI "int ibv_dereg_mr(struct ibv_mr " "*mr" );
  .fi
  .SH "DESCRIPTION"
@@ -71,11 +74,25 @@ a lkey or rkey. The offset in the memory region is computed as 'addr +
  (iova - hca_va)'. Specifying 0 for hca_va has the same effect as
  IBV_ACCESS_ZERO_BASED.
  .PP
+.B ibv_reg_dmabuf_mr()
+registers a dma-buf based memory region (MR) associated with the protection domain
+.I pd\fR.
+The MR starts at
+.I offset
+of the dma-buf and its size is
+.I length\fR.
+The dma-buf is identified by the file descriptor
+.I fd\fR.
+The argument
+.I access
+describes the desired memory protection attributes; it is similar to the ibv_reg_mr case except that only the following flags are supported:
+.B IBV_ACCESS_LOCAL_WRITE, IBV_ACCESS_REMOTE_WRITE, IBV_ACCESS_REMOTE_READ, IBV_ACCESS_REMOTE_ATOMIC, IBV_ACCESS_RELAXED_ORDERING.
+.PP
  .B ibv_dereg_mr()
  deregisters the MR
  .I mr\fR.
  .SH "RETURN VALUE"
-.B ibv_reg_mr() / ibv_reg_mr_iova()
+.B ibv_reg_mr() / ibv_reg_mr_iova() / ibv_reg_dmabuf_mr()
  returns a pointer to the registered MR, or NULL if the request fails.
  The local key (\fBL_Key\fR) field
  .B lkey
diff --git a/libibverbs/verbs.c b/libibverbs/verbs.c
index 2b0ede8..84ddac7 100644
--- a/libibverbs/verbs.c
+++ b/libibverbs/verbs.c
@@ -1,6 +1,7 @@
  /*
   * Copyright (c) 2005 Topspin Communications.  All rights reserved.
   * Copyright (c) 2006, 2007 Cisco Systems, Inc.  All rights reserved.
+ * Copyright (c) 2020 Intel Corperation.  All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
@@ -367,6 +368,24 @@ void ibv_unimport_mr(struct ibv_mr *mr)
  	get_ops(mr->context)->unimport_mr(mr);
  }
  
+LATEST_SYMVER_FUNC(ibv_reg_dmabuf_mr, 1_12, "IBVERBS_1.12",
+		   struct ibv_mr *,
+		   struct ibv_pd *pd, uint64_t offset,
+		   size_t length, int fd, int access)
+{


 ibv_dereg_mr() -> ibv_dofork_range() doesn't seem to be applicable in 
this case, right ? if offset / addr won't be 0 it may be activated on 
the address range.

Do we rely on applications to *not* turn on fork support in libibverbs ? 
(e.g. call ibv_fork_init()), what if some other registrations may need 
being fork safe ?

+	struct ibv_mr *mr;
+
+	mr = get_ops(pd->context)->reg_dmabuf_mr(pd, offset, length, offset,
+						 fd, access);
+	if (mr) {
+		mr->context = pd->context;
+		mr->pd      = pd;
+		mr->addr    = (void *)offset;
+		mr->length  = length;
+	}
+	return mr;
+}
+
  LATEST_SYMVER_FUNC(ibv_rereg_mr, 1_1, "IBVERBS_1.1",
  		   int,
  		   struct ibv_mr *mr, int flags,
diff --git a/libibverbs/verbs.h b/libibverbs/verbs.h
index ee57e05..3961b1e 100644
--- a/libibverbs/verbs.h
+++ b/libibverbs/verbs.h
@@ -3,6 +3,7 @@
   * Copyright (c) 2004, 2011-2012 Intel Corporation.  All rights reserved.
   * Copyright (c) 2005, 2006, 2007 Cisco Systems, Inc.  All rights reserved.
   * Copyright (c) 2005 PathScale, Inc.  All rights reserved.
+ * Copyright (c) 2020 Intel Corporation.  All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
@@ -2133,6 +2134,9 @@ struct verbs_context {
  	struct ibv_xrcd *	(*open_xrcd)(struct ibv_context *context,
  					     struct ibv_xrcd_init_attr *xrcd_init_attr);
  	int			(*close_xrcd)(struct ibv_xrcd *xrcd);
+	struct ibv_mr *		(*reg_dmabuf_mr)(struct ibv_pd *pd, uint64_t offset,
+						 size_t length, uint64_t iova,
+						 int fd, int access);
  	uint64_t _ABI_placeholder3;
  	size_t   sz;			/* Must be immediately before struct ibv_context */
  	struct ibv_context context;	/* Must be last field in the struct */
@@ -2535,6 +2539,12 @@ __ibv_reg_mr_iova(struct ibv_pd *pd, void *addr, size_t length, uint64_t iova,
  			  __builtin_constant_p(                                \
  				  ((access) & IBV_ACCESS_OPTIONAL_RANGE) == 0))
  
+/**
+ * ibv_reg_dmabuf_mr - Register a dambuf-based memory region
+ */
+struct ibv_mr *ibv_reg_dmabuf_mr(struct ibv_pd *pd, uint64_t offset, size_t length,
+				 int fd, int access);
+
  enum ibv_rereg_mr_err_code {
  	/* Old MR is valid, invalid input */
  	IBV_REREG_MR_ERR_INPUT = -1,


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