diff mbox series

[rdma-next,6/7] RDMA/mlx5: Add support in MEMIC operations

Message ID 20210318111548.674749-7-leon@kernel.org (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series Add MEMIC operations support | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch

Commit Message

Leon Romanovsky March 18, 2021, 11:15 a.m. UTC 
From: Maor Gottlieb <maorg@nvidia.com>

MEMIC buffer, in addition to regular read and write operations, can
support atomic operations from the host.

Introduce and implement new UAPI to allocate address space for MEMIC
operations such as atomic. This includes:

1. Expose new IOCTL for request mapping of MEMIC operation.
2. Hold the operations address in a list, so same operation to same DM
   will be allocated only once.
3. Manage refcount on the mlx5_ib_dm object, so it would be keep valid
   until all addresses were unmapped.

Signed-off-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/hw/mlx5/dm.c          | 196 +++++++++++++++++++++--
 drivers/infiniband/hw/mlx5/dm.h          |   2 +
 drivers/infiniband/hw/mlx5/main.c        |   7 +-
 drivers/infiniband/hw/mlx5/mlx5_ib.h     |  16 +-
 include/uapi/rdma/mlx5_user_ioctl_cmds.h |  11 ++
 5 files changed, 214 insertions(+), 18 deletions(-)

--
2.30.2

Comments

Jason Gunthorpe April 1, 2021, 5:47 p.m. UTC | #1 
On Thu, Mar 18, 2021 at 01:15:47PM +0200, Leon Romanovsky wrote:
> From: Maor Gottlieb <maorg@nvidia.com>
> 
> MEMIC buffer, in addition to regular read and write operations, can
> support atomic operations from the host.
> 
> Introduce and implement new UAPI to allocate address space for MEMIC
> operations such as atomic. This includes:
> 
> 1. Expose new IOCTL for request mapping of MEMIC operation.
> 2. Hold the operations address in a list, so same operation to same DM
>    will be allocated only once.
> 3. Manage refcount on the mlx5_ib_dm object, so it would be keep valid
>    until all addresses were unmapped.
> 
> Signed-off-by: Maor Gottlieb <maorg@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/infiniband/hw/mlx5/dm.c          | 196 +++++++++++++++++++++--
>  drivers/infiniband/hw/mlx5/dm.h          |   2 +
>  drivers/infiniband/hw/mlx5/main.c        |   7 +-
>  drivers/infiniband/hw/mlx5/mlx5_ib.h     |  16 +-
>  include/uapi/rdma/mlx5_user_ioctl_cmds.h |  11 ++
>  5 files changed, 214 insertions(+), 18 deletions(-)
> 
> --
> 2.30.2
> 
> diff --git a/drivers/infiniband/hw/mlx5/dm.c b/drivers/infiniband/hw/mlx5/dm.c
> index 97a925d43312..ee4ee197a626 100644
> --- a/drivers/infiniband/hw/mlx5/dm.c
> +++ b/drivers/infiniband/hw/mlx5/dm.c
> @@ -150,12 +150,14 @@ static int mlx5_cmd_alloc_memic_op(struct mlx5_dm *dm, phys_addr_t addr,
>  }
> 
>  static int add_dm_mmap_entry(struct ib_ucontext *context,
> -			     struct mlx5_ib_dm *mdm, u64 address)
> +			     struct mlx5_user_mmap_entry *mentry, u8 mmap_flag,
> +			     size_t size, u64 address)
>  {
> -	mdm->mentry.mmap_flag = MLX5_IB_MMAP_TYPE_MEMIC;
> -	mdm->mentry.address = address;
> +	mentry->mmap_flag = mmap_flag;
> +	mentry->address = address;
> +
>  	return rdma_user_mmap_entry_insert_range(
> -		context, &mdm->mentry.rdma_entry, mdm->size,
> +		context, &mentry->rdma_entry, size,
>  		MLX5_IB_MMAP_DEVICE_MEM << 16,
>  		(MLX5_IB_MMAP_DEVICE_MEM << 16) + (1UL << 16) - 1);
>  }
> @@ -183,6 +185,114 @@ static inline int check_dm_type_support(struct mlx5_ib_dev *dev, u32 type)
>  	return 0;
>  }
> 
> +void mlx5_ib_dm_memic_free(struct kref *kref)
> +{
> +	struct mlx5_ib_dm *dm =
> +		container_of(kref, struct mlx5_ib_dm, memic.ref);
> +	struct mlx5_ib_dev *dev = to_mdev(dm->ibdm.device);
> +
> +	mlx5_cmd_dealloc_memic(&dev->dm, dm->dev_addr, dm->size);
> +	kfree(dm);
> +}
> +
> +static int copy_op_to_user(struct mlx5_ib_dm_op_entry *op_entry,
> +			   struct uverbs_attr_bundle *attrs)
> +{
> +	u64 start_offset;
> +	u16 page_idx;
> +	int err;
> +
> +	page_idx = op_entry->mentry.rdma_entry.start_pgoff & 0xFFFF;
> +	start_offset = op_entry->op_addr & ~PAGE_MASK;
> +	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_PAGE_INDEX,
> +			     &page_idx, sizeof(page_idx));
> +	if (err)
> +		return err;
> +
> +	return uverbs_copy_to(attrs,
> +			      MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_START_OFFSET,
> +			      &start_offset, sizeof(start_offset));
> +}
> +
> +static int map_existing_op(struct mlx5_ib_dm *dm, u8 op,
> +			   struct uverbs_attr_bundle *attrs)
> +{
> +	struct mlx5_ib_dm_op_entry *op_entry;
> +
> +	op_entry = xa_load(&dm->memic.ops, op);
> +	if (!op_entry)
> +		return -ENOENT;
> +
> +	return copy_op_to_user(op_entry, attrs);
> +}
> +
> +static int UVERBS_HANDLER(MLX5_IB_METHOD_DM_MAP_OP_ADDR)(
> +	struct uverbs_attr_bundle *attrs)
> +{
> +	struct ib_uobject *uobj = uverbs_attr_get_uobject(
> +		attrs, MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_HANDLE);
> +	struct mlx5_ib_dev *dev = to_mdev(uobj->context->device);
> +	struct ib_dm *ibdm = uobj->object;
> +	struct mlx5_ib_dm *dm = to_mdm(ibdm);
> +	struct mlx5_ib_dm_op_entry *op_entry;
> +	int err;
> +	u8 op;
> +
> +	err = uverbs_copy_from(&op, attrs, MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_OP);
> +	if (err)
> +		return err;
> +
> +	if (!(MLX5_CAP_DEV_MEM(dev->mdev, memic_operations) & BIT(op)))
> +		return -EOPNOTSUPP;
> +
> +	mutex_lock(&dm->memic.ops_xa_lock);
> +	err = map_existing_op(dm, op, attrs);
> +	if (!err || err != -ENOENT)
> +		goto err_unlock;
> +
> +	op_entry = kzalloc(sizeof(*op_entry), GFP_KERNEL);
> +	if (!op_entry)
> +		goto err_unlock;
> +
> +	err = mlx5_cmd_alloc_memic_op(&dev->dm, dm->dev_addr, op,
> +				      &op_entry->op_addr);
> +	if (err) {
> +		kfree(op_entry);
> +		goto err_unlock;
> +	}
> +	op_entry->op = op;
> +	op_entry->dm = dm;
> +
> +	err = add_dm_mmap_entry(uobj->context, &op_entry->mentry,
> +				MLX5_IB_MMAP_TYPE_MEMIC_OP, dm->size,
> +				op_entry->op_addr & PAGE_MASK);
> +	if (err) {
> +		mlx5_cmd_dealloc_memic_op(&dev->dm, dm->dev_addr, op);
> +		kfree(op_entry);
> +		goto err_unlock;
> +	}
> +	/* From this point, entry will be freed by mmap_free */
> +	kref_get(&dm->memic.ref);
> +
> +	err = copy_op_to_user(op_entry, attrs);
> +	if (err)
> +		goto err_remove;
> +
> +	err = xa_insert(&dm->memic.ops, op, op_entry, GFP_KERNEL);
> +	if (err)
> +		goto err_remove;
> +	mutex_unlock(&dm->memic.ops_xa_lock);
> +
> +	return 0;
> +
> +err_remove:
> +	rdma_user_mmap_entry_remove(&op_entry->mentry.rdma_entry);
> +err_unlock:
> +	mutex_unlock(&dm->memic.ops_xa_lock);
> +
> +	return err;
> +}
> +
>  static int handle_alloc_dm_memic(struct ib_ucontext *ctx, struct mlx5_ib_dm *dm,
>  				 struct ib_dm_alloc_attr *attr,
>  				 struct uverbs_attr_bundle *attrs)
> @@ -193,6 +303,9 @@ static int handle_alloc_dm_memic(struct ib_ucontext *ctx, struct mlx5_ib_dm *dm,
>  	int err;
>  	u64 address;
> 
> +	kref_init(&dm->memic.ref);
> +	xa_init(&dm->memic.ops);
> +	mutex_init(&dm->memic.ops_xa_lock);
>  	dm->size = roundup(attr->length, MLX5_MEMIC_BASE_SIZE);
> 
>  	err = mlx5_cmd_alloc_memic(dm_db, &dm->dev_addr,
> @@ -203,18 +316,17 @@ static int handle_alloc_dm_memic(struct ib_ucontext *ctx, struct mlx5_ib_dm *dm,
>  	}
> 
>  	address = dm->dev_addr & PAGE_MASK;
> -	err = add_dm_mmap_entry(ctx, dm, address);
> +	err = add_dm_mmap_entry(ctx, &dm->memic.mentry, MLX5_IB_MMAP_TYPE_MEMIC,
> +				dm->size, address);
>  	if (err) {
>  		mlx5_cmd_dealloc_memic(dm_db, dm->dev_addr, dm->size);
>  		kfree(dm);
>  		return err;
>  	}
> 
> -	page_idx = dm->mentry.rdma_entry.start_pgoff & 0xFFFF;
> -	err = uverbs_copy_to(attrs,
> -			     MLX5_IB_ATTR_ALLOC_DM_RESP_PAGE_INDEX,
> -			     &page_idx,
> -			     sizeof(page_idx));
> +	page_idx = dm->memic.mentry.rdma_entry.start_pgoff & 0xFFFF;
> +	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_ALLOC_DM_RESP_PAGE_INDEX,
> +			     &page_idx, sizeof(page_idx));
>  	if (err)
>  		goto err_copy;
> 
> @@ -228,7 +340,7 @@ static int handle_alloc_dm_memic(struct ib_ucontext *ctx, struct mlx5_ib_dm *dm,
>  	return 0;
> 
>  err_copy:
> -	rdma_user_mmap_entry_remove(&dm->mentry.rdma_entry);
> +	rdma_user_mmap_entry_remove(&dm->memic.mentry.rdma_entry);
> 
>  	return err;
>  }
> @@ -292,6 +404,7 @@ struct ib_dm *mlx5_ib_alloc_dm(struct ib_device *ibdev,
>  		return ERR_PTR(-ENOMEM);
> 
>  	dm->type = type;
> +	dm->ibdm.device = ibdev;
> 
>  	switch (type) {
>  	case MLX5_IB_UAPI_DM_TYPE_MEMIC:
> @@ -323,6 +436,19 @@ struct ib_dm *mlx5_ib_alloc_dm(struct ib_device *ibdev,
>  	return ERR_PTR(err);
>  }
> 
> +static void dm_memic_remove_ops(struct mlx5_ib_dm *dm)
> +{
> +	struct mlx5_ib_dm_op_entry *entry;
> +	unsigned long idx;
> +
> +	mutex_lock(&dm->memic.ops_xa_lock);
> +	xa_for_each(&dm->memic.ops, idx, entry) {
> +		xa_erase(&dm->memic.ops, idx);
> +		rdma_user_mmap_entry_remove(&entry->mentry.rdma_entry);
> +	}
> +	mutex_unlock(&dm->memic.ops_xa_lock);
> +}
> +
>  int mlx5_ib_dealloc_dm(struct ib_dm *ibdm, struct uverbs_attr_bundle *attrs)
>  {
>  	struct mlx5_ib_ucontext *ctx = rdma_udata_to_drv_context(
> @@ -333,7 +459,8 @@ int mlx5_ib_dealloc_dm(struct ib_dm *ibdm, struct uverbs_attr_bundle *attrs)
> 
>  	switch (dm->type) {
>  	case MLX5_IB_UAPI_DM_TYPE_MEMIC:
> -		rdma_user_mmap_entry_remove(&dm->mentry.rdma_entry);
> +		dm_memic_remove_ops(dm);
> +		rdma_user_mmap_entry_remove(&dm->memic.mentry.rdma_entry);
>  		return 0;
>  	case MLX5_IB_UAPI_DM_TYPE_STEERING_SW_ICM:
>  		ret = mlx5_dm_sw_icm_dealloc(dev, MLX5_SW_ICM_TYPE_STEERING,
> @@ -359,6 +486,31 @@ int mlx5_ib_dealloc_dm(struct ib_dm *ibdm, struct uverbs_attr_bundle *attrs)
>  	return 0;
>  }
> 
> +void mlx5_ib_dm_mmap_free(struct mlx5_ib_dev *dev,
> +			  struct mlx5_user_mmap_entry *mentry)
> +{
> +	struct mlx5_ib_dm_op_entry *op_entry;
> +	struct mlx5_ib_dm *mdm;
> +
> +	switch (mentry->mmap_flag) {
> +	case MLX5_IB_MMAP_TYPE_MEMIC:
> +		mdm = container_of(mentry, struct mlx5_ib_dm, memic.mentry);
> +		kref_put(&mdm->memic.ref, mlx5_ib_dm_memic_free);
> +		break;
> +	case MLX5_IB_MMAP_TYPE_MEMIC_OP:
> +		op_entry = container_of(mentry, struct mlx5_ib_dm_op_entry,
> +					mentry);
> +		mdm = op_entry->dm;
> +		mlx5_cmd_dealloc_memic_op(&dev->dm, mdm->dev_addr,
> +					  op_entry->op);
> +		kfree(op_entry);
> +		kref_put(&mdm->memic.ref, mlx5_ib_dm_memic_free);
> +		break;
> +	default:
> +		WARN_ON(true);
> +	}
> +}
> +
>  ADD_UVERBS_ATTRIBUTES_SIMPLE(
>  	mlx5_ib_dm, UVERBS_OBJECT_DM, UVERBS_METHOD_DM_ALLOC,
>  	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_ALLOC_DM_RESP_START_OFFSET,
> @@ -368,8 +520,28 @@ ADD_UVERBS_ATTRIBUTES_SIMPLE(
>  	UVERBS_ATTR_CONST_IN(MLX5_IB_ATTR_ALLOC_DM_REQ_TYPE,
>  			     enum mlx5_ib_uapi_dm_type, UA_OPTIONAL));
> 
> +DECLARE_UVERBS_NAMED_METHOD(
> +	MLX5_IB_METHOD_DM_MAP_OP_ADDR,
> +	UVERBS_ATTR_IDR(MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_HANDLE,
> +			UVERBS_OBJECT_DM,
> +			UVERBS_ACCESS_READ,
> +			UA_MANDATORY),
> +	UVERBS_ATTR_PTR_IN(MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_OP,
> +			   UVERBS_ATTR_TYPE(u8),
> +			   UA_MANDATORY),
> +	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_START_OFFSET,
> +			    UVERBS_ATTR_TYPE(u64),
> +			    UA_MANDATORY),
> +	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_PAGE_INDEX,
> +			    UVERBS_ATTR_TYPE(u16),
> +			    UA_OPTIONAL));
> +
> +DECLARE_UVERBS_GLOBAL_METHODS(UVERBS_OBJECT_DM,
> +			      &UVERBS_METHOD(MLX5_IB_METHOD_DM_MAP_OP_ADDR));
> +
>  const struct uapi_definition mlx5_ib_dm_defs[] = {
>  	UAPI_DEF_CHAIN_OBJ_TREE(UVERBS_OBJECT_DM, &mlx5_ib_dm),
> +	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_DM),
>  	{},
>  };
> 
> diff --git a/drivers/infiniband/hw/mlx5/dm.h b/drivers/infiniband/hw/mlx5/dm.h
> index adb39d3d8131..56cf1ba9c985 100644
> --- a/drivers/infiniband/hw/mlx5/dm.h
> +++ b/drivers/infiniband/hw/mlx5/dm.h
> @@ -8,6 +8,8 @@
> 
>  #include "mlx5_ib.h"
> 
> +void mlx5_ib_dm_mmap_free(struct mlx5_ib_dev *dev,
> +			  struct mlx5_user_mmap_entry *mentry);
>  void mlx5_cmd_dealloc_memic(struct mlx5_dm *dm, phys_addr_t addr,
>  			    u64 length);
>  void mlx5_cmd_dealloc_memic_op(struct mlx5_dm *dm, phys_addr_t addr,
> diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
> index 49c8c60d9520..6908db28b796 100644
> --- a/drivers/infiniband/hw/mlx5/main.c
> +++ b/drivers/infiniband/hw/mlx5/main.c
> @@ -2090,14 +2090,11 @@ static void mlx5_ib_mmap_free(struct rdma_user_mmap_entry *entry)
>  	struct mlx5_user_mmap_entry *mentry = to_mmmap(entry);
>  	struct mlx5_ib_dev *dev = to_mdev(entry->ucontext->device);
>  	struct mlx5_var_table *var_table = &dev->var_table;
> -	struct mlx5_ib_dm *mdm;
> 
>  	switch (mentry->mmap_flag) {
>  	case MLX5_IB_MMAP_TYPE_MEMIC:
> -		mdm = container_of(mentry, struct mlx5_ib_dm, mentry);
> -		mlx5_cmd_dealloc_memic(&dev->dm, mdm->dev_addr,
> -				       mdm->size);
> -		kfree(mdm);
> +	case MLX5_IB_MMAP_TYPE_MEMIC_OP:
> +		mlx5_ib_dm_mmap_free(dev, mentry);
>  		break;
>  	case MLX5_IB_MMAP_TYPE_VAR:
>  		mutex_lock(&var_table->bitmap_lock);
> diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
> index ae971de6e934..b714131f87b7 100644
> --- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
> +++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
> @@ -166,6 +166,7 @@ enum mlx5_ib_mmap_type {
>  	MLX5_IB_MMAP_TYPE_VAR = 2,
>  	MLX5_IB_MMAP_TYPE_UAR_WC = 3,
>  	MLX5_IB_MMAP_TYPE_UAR_NC = 4,
> +	MLX5_IB_MMAP_TYPE_MEMIC_OP = 5,
>  };
> 
>  struct mlx5_bfreg_info {
> @@ -618,18 +619,30 @@ struct mlx5_user_mmap_entry {
>  	u32 page_idx;
>  };
> 
> +struct mlx5_ib_dm_op_entry {
> +	struct mlx5_user_mmap_entry	mentry;
> +	phys_addr_t			op_addr;
> +	struct mlx5_ib_dm		*dm;
> +	u8				op;
> +};
> +
>  struct mlx5_ib_dm {
>  	struct ib_dm		ibdm;
>  	phys_addr_t		dev_addr;
>  	u32			type;
>  	size_t			size;
>  	union {
> +		struct {
> +				struct mlx5_user_mmap_entry mentry;
> +				struct xarray		ops;
> +				struct mutex		ops_xa_lock;
> +				struct kref		ref;
> +		} memic;
>  		struct {
>  			u32	obj_id;
>  		} icm_dm;

This union is making it much too difficult to read and understand now.
An optional kref inside a structure is too far

Please split it to more types and have proper typesafety throughout

It looks mostly fine otherwise, the error flows are a bit hard to read
though, when a new type is added this should also get re-organized so
we don't do stuff like:

err_free:
	/* In MEMIC error flow, dm will be freed internally */
	if (type != MLX5_IB_UAPI_DM_TYPE_MEMIC)
		kfree(dm);

I'd inline the checks from check_dm_type_support() into their
respective allocation functions too

Jason
Leon Romanovsky April 4, 2021, 7:51 a.m. UTC | #2 
On Thu, Apr 01, 2021 at 02:47:04PM -0300, Jason Gunthorpe wrote:
> On Thu, Mar 18, 2021 at 01:15:47PM +0200, Leon Romanovsky wrote:
> > From: Maor Gottlieb <maorg@nvidia.com>
> > 
> > MEMIC buffer, in addition to regular read and write operations, can
> > support atomic operations from the host.
> > 
> > Introduce and implement new UAPI to allocate address space for MEMIC
> > operations such as atomic. This includes:

<...>

> It looks mostly fine otherwise, the error flows are a bit hard to read
> though, when a new type is added this should also get re-organized so
> we don't do stuff like:
> 
> err_free:
> 	/* In MEMIC error flow, dm will be freed internally */
> 	if (type != MLX5_IB_UAPI_DM_TYPE_MEMIC)
> 		kfree(dm);

I actually liked it, because the "re-organized" code was harder to read
than this simple check. but ok, let's try again.

Thanks
diff mbox series

Patch

diff --git a/drivers/infiniband/hw/mlx5/dm.c b/drivers/infiniband/hw/mlx5/dm.c
index 97a925d43312..ee4ee197a626 100644
--- a/drivers/infiniband/hw/mlx5/dm.c
+++ b/drivers/infiniband/hw/mlx5/dm.c
@@ -150,12 +150,14 @@  static int mlx5_cmd_alloc_memic_op(struct mlx5_dm *dm, phys_addr_t addr,
 }

 static int add_dm_mmap_entry(struct ib_ucontext *context,
-			     struct mlx5_ib_dm *mdm, u64 address)
+			     struct mlx5_user_mmap_entry *mentry, u8 mmap_flag,
+			     size_t size, u64 address)
 {
-	mdm->mentry.mmap_flag = MLX5_IB_MMAP_TYPE_MEMIC;
-	mdm->mentry.address = address;
+	mentry->mmap_flag = mmap_flag;
+	mentry->address = address;
+
 	return rdma_user_mmap_entry_insert_range(
-		context, &mdm->mentry.rdma_entry, mdm->size,
+		context, &mentry->rdma_entry, size,
 		MLX5_IB_MMAP_DEVICE_MEM << 16,
 		(MLX5_IB_MMAP_DEVICE_MEM << 16) + (1UL << 16) - 1);
 }
@@ -183,6 +185,114 @@  static inline int check_dm_type_support(struct mlx5_ib_dev *dev, u32 type)
 	return 0;
 }

+void mlx5_ib_dm_memic_free(struct kref *kref)
+{
+	struct mlx5_ib_dm *dm =
+		container_of(kref, struct mlx5_ib_dm, memic.ref);
+	struct mlx5_ib_dev *dev = to_mdev(dm->ibdm.device);
+
+	mlx5_cmd_dealloc_memic(&dev->dm, dm->dev_addr, dm->size);
+	kfree(dm);
+}
+
+static int copy_op_to_user(struct mlx5_ib_dm_op_entry *op_entry,
+			   struct uverbs_attr_bundle *attrs)
+{
+	u64 start_offset;
+	u16 page_idx;
+	int err;
+
+	page_idx = op_entry->mentry.rdma_entry.start_pgoff & 0xFFFF;
+	start_offset = op_entry->op_addr & ~PAGE_MASK;
+	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_PAGE_INDEX,
+			     &page_idx, sizeof(page_idx));
+	if (err)
+		return err;
+
+	return uverbs_copy_to(attrs,
+			      MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_START_OFFSET,
+			      &start_offset, sizeof(start_offset));
+}
+
+static int map_existing_op(struct mlx5_ib_dm *dm, u8 op,
+			   struct uverbs_attr_bundle *attrs)
+{
+	struct mlx5_ib_dm_op_entry *op_entry;
+
+	op_entry = xa_load(&dm->memic.ops, op);
+	if (!op_entry)
+		return -ENOENT;
+
+	return copy_op_to_user(op_entry, attrs);
+}
+
+static int UVERBS_HANDLER(MLX5_IB_METHOD_DM_MAP_OP_ADDR)(
+	struct uverbs_attr_bundle *attrs)
+{
+	struct ib_uobject *uobj = uverbs_attr_get_uobject(
+		attrs, MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_HANDLE);
+	struct mlx5_ib_dev *dev = to_mdev(uobj->context->device);
+	struct ib_dm *ibdm = uobj->object;
+	struct mlx5_ib_dm *dm = to_mdm(ibdm);
+	struct mlx5_ib_dm_op_entry *op_entry;
+	int err;
+	u8 op;
+
+	err = uverbs_copy_from(&op, attrs, MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_OP);
+	if (err)
+		return err;
+
+	if (!(MLX5_CAP_DEV_MEM(dev->mdev, memic_operations) & BIT(op)))
+		return -EOPNOTSUPP;
+
+	mutex_lock(&dm->memic.ops_xa_lock);
+	err = map_existing_op(dm, op, attrs);
+	if (!err || err != -ENOENT)
+		goto err_unlock;
+
+	op_entry = kzalloc(sizeof(*op_entry), GFP_KERNEL);
+	if (!op_entry)
+		goto err_unlock;
+
+	err = mlx5_cmd_alloc_memic_op(&dev->dm, dm->dev_addr, op,
+				      &op_entry->op_addr);
+	if (err) {
+		kfree(op_entry);
+		goto err_unlock;
+	}
+	op_entry->op = op;
+	op_entry->dm = dm;
+
+	err = add_dm_mmap_entry(uobj->context, &op_entry->mentry,
+				MLX5_IB_MMAP_TYPE_MEMIC_OP, dm->size,
+				op_entry->op_addr & PAGE_MASK);
+	if (err) {
+		mlx5_cmd_dealloc_memic_op(&dev->dm, dm->dev_addr, op);
+		kfree(op_entry);
+		goto err_unlock;
+	}
+	/* From this point, entry will be freed by mmap_free */
+	kref_get(&dm->memic.ref);
+
+	err = copy_op_to_user(op_entry, attrs);
+	if (err)
+		goto err_remove;
+
+	err = xa_insert(&dm->memic.ops, op, op_entry, GFP_KERNEL);
+	if (err)
+		goto err_remove;
+	mutex_unlock(&dm->memic.ops_xa_lock);
+
+	return 0;
+
+err_remove:
+	rdma_user_mmap_entry_remove(&op_entry->mentry.rdma_entry);
+err_unlock:
+	mutex_unlock(&dm->memic.ops_xa_lock);
+
+	return err;
+}
+
 static int handle_alloc_dm_memic(struct ib_ucontext *ctx, struct mlx5_ib_dm *dm,
 				 struct ib_dm_alloc_attr *attr,
 				 struct uverbs_attr_bundle *attrs)
@@ -193,6 +303,9 @@  static int handle_alloc_dm_memic(struct ib_ucontext *ctx, struct mlx5_ib_dm *dm,
 	int err;
 	u64 address;

+	kref_init(&dm->memic.ref);
+	xa_init(&dm->memic.ops);
+	mutex_init(&dm->memic.ops_xa_lock);
 	dm->size = roundup(attr->length, MLX5_MEMIC_BASE_SIZE);

 	err = mlx5_cmd_alloc_memic(dm_db, &dm->dev_addr,
@@ -203,18 +316,17 @@  static int handle_alloc_dm_memic(struct ib_ucontext *ctx, struct mlx5_ib_dm *dm,
 	}

 	address = dm->dev_addr & PAGE_MASK;
-	err = add_dm_mmap_entry(ctx, dm, address);
+	err = add_dm_mmap_entry(ctx, &dm->memic.mentry, MLX5_IB_MMAP_TYPE_MEMIC,
+				dm->size, address);
 	if (err) {
 		mlx5_cmd_dealloc_memic(dm_db, dm->dev_addr, dm->size);
 		kfree(dm);
 		return err;
 	}

-	page_idx = dm->mentry.rdma_entry.start_pgoff & 0xFFFF;
-	err = uverbs_copy_to(attrs,
-			     MLX5_IB_ATTR_ALLOC_DM_RESP_PAGE_INDEX,
-			     &page_idx,
-			     sizeof(page_idx));
+	page_idx = dm->memic.mentry.rdma_entry.start_pgoff & 0xFFFF;
+	err = uverbs_copy_to(attrs, MLX5_IB_ATTR_ALLOC_DM_RESP_PAGE_INDEX,
+			     &page_idx, sizeof(page_idx));
 	if (err)
 		goto err_copy;

@@ -228,7 +340,7 @@  static int handle_alloc_dm_memic(struct ib_ucontext *ctx, struct mlx5_ib_dm *dm,
 	return 0;

 err_copy:
-	rdma_user_mmap_entry_remove(&dm->mentry.rdma_entry);
+	rdma_user_mmap_entry_remove(&dm->memic.mentry.rdma_entry);

 	return err;
 }
@@ -292,6 +404,7 @@  struct ib_dm *mlx5_ib_alloc_dm(struct ib_device *ibdev,
 		return ERR_PTR(-ENOMEM);

 	dm->type = type;
+	dm->ibdm.device = ibdev;

 	switch (type) {
 	case MLX5_IB_UAPI_DM_TYPE_MEMIC:
@@ -323,6 +436,19 @@  struct ib_dm *mlx5_ib_alloc_dm(struct ib_device *ibdev,
 	return ERR_PTR(err);
 }

+static void dm_memic_remove_ops(struct mlx5_ib_dm *dm)
+{
+	struct mlx5_ib_dm_op_entry *entry;
+	unsigned long idx;
+
+	mutex_lock(&dm->memic.ops_xa_lock);
+	xa_for_each(&dm->memic.ops, idx, entry) {
+		xa_erase(&dm->memic.ops, idx);
+		rdma_user_mmap_entry_remove(&entry->mentry.rdma_entry);
+	}
+	mutex_unlock(&dm->memic.ops_xa_lock);
+}
+
 int mlx5_ib_dealloc_dm(struct ib_dm *ibdm, struct uverbs_attr_bundle *attrs)
 {
 	struct mlx5_ib_ucontext *ctx = rdma_udata_to_drv_context(
@@ -333,7 +459,8 @@  int mlx5_ib_dealloc_dm(struct ib_dm *ibdm, struct uverbs_attr_bundle *attrs)

 	switch (dm->type) {
 	case MLX5_IB_UAPI_DM_TYPE_MEMIC:
-		rdma_user_mmap_entry_remove(&dm->mentry.rdma_entry);
+		dm_memic_remove_ops(dm);
+		rdma_user_mmap_entry_remove(&dm->memic.mentry.rdma_entry);
 		return 0;
 	case MLX5_IB_UAPI_DM_TYPE_STEERING_SW_ICM:
 		ret = mlx5_dm_sw_icm_dealloc(dev, MLX5_SW_ICM_TYPE_STEERING,
@@ -359,6 +486,31 @@  int mlx5_ib_dealloc_dm(struct ib_dm *ibdm, struct uverbs_attr_bundle *attrs)
 	return 0;
 }

+void mlx5_ib_dm_mmap_free(struct mlx5_ib_dev *dev,
+			  struct mlx5_user_mmap_entry *mentry)
+{
+	struct mlx5_ib_dm_op_entry *op_entry;
+	struct mlx5_ib_dm *mdm;
+
+	switch (mentry->mmap_flag) {
+	case MLX5_IB_MMAP_TYPE_MEMIC:
+		mdm = container_of(mentry, struct mlx5_ib_dm, memic.mentry);
+		kref_put(&mdm->memic.ref, mlx5_ib_dm_memic_free);
+		break;
+	case MLX5_IB_MMAP_TYPE_MEMIC_OP:
+		op_entry = container_of(mentry, struct mlx5_ib_dm_op_entry,
+					mentry);
+		mdm = op_entry->dm;
+		mlx5_cmd_dealloc_memic_op(&dev->dm, mdm->dev_addr,
+					  op_entry->op);
+		kfree(op_entry);
+		kref_put(&mdm->memic.ref, mlx5_ib_dm_memic_free);
+		break;
+	default:
+		WARN_ON(true);
+	}
+}
+
 ADD_UVERBS_ATTRIBUTES_SIMPLE(
 	mlx5_ib_dm, UVERBS_OBJECT_DM, UVERBS_METHOD_DM_ALLOC,
 	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_ALLOC_DM_RESP_START_OFFSET,
@@ -368,8 +520,28 @@  ADD_UVERBS_ATTRIBUTES_SIMPLE(
 	UVERBS_ATTR_CONST_IN(MLX5_IB_ATTR_ALLOC_DM_REQ_TYPE,
 			     enum mlx5_ib_uapi_dm_type, UA_OPTIONAL));

+DECLARE_UVERBS_NAMED_METHOD(
+	MLX5_IB_METHOD_DM_MAP_OP_ADDR,
+	UVERBS_ATTR_IDR(MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_HANDLE,
+			UVERBS_OBJECT_DM,
+			UVERBS_ACCESS_READ,
+			UA_MANDATORY),
+	UVERBS_ATTR_PTR_IN(MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_OP,
+			   UVERBS_ATTR_TYPE(u8),
+			   UA_MANDATORY),
+	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_START_OFFSET,
+			    UVERBS_ATTR_TYPE(u64),
+			    UA_MANDATORY),
+	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_PAGE_INDEX,
+			    UVERBS_ATTR_TYPE(u16),
+			    UA_OPTIONAL));
+
+DECLARE_UVERBS_GLOBAL_METHODS(UVERBS_OBJECT_DM,
+			      &UVERBS_METHOD(MLX5_IB_METHOD_DM_MAP_OP_ADDR));
+
 const struct uapi_definition mlx5_ib_dm_defs[] = {
 	UAPI_DEF_CHAIN_OBJ_TREE(UVERBS_OBJECT_DM, &mlx5_ib_dm),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(UVERBS_OBJECT_DM),
 	{},
 };

diff --git a/drivers/infiniband/hw/mlx5/dm.h b/drivers/infiniband/hw/mlx5/dm.h
index adb39d3d8131..56cf1ba9c985 100644
--- a/drivers/infiniband/hw/mlx5/dm.h
+++ b/drivers/infiniband/hw/mlx5/dm.h
@@ -8,6 +8,8 @@ 

 #include "mlx5_ib.h"

+void mlx5_ib_dm_mmap_free(struct mlx5_ib_dev *dev,
+			  struct mlx5_user_mmap_entry *mentry);
 void mlx5_cmd_dealloc_memic(struct mlx5_dm *dm, phys_addr_t addr,
 			    u64 length);
 void mlx5_cmd_dealloc_memic_op(struct mlx5_dm *dm, phys_addr_t addr,
diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 49c8c60d9520..6908db28b796 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -2090,14 +2090,11 @@  static void mlx5_ib_mmap_free(struct rdma_user_mmap_entry *entry)
 	struct mlx5_user_mmap_entry *mentry = to_mmmap(entry);
 	struct mlx5_ib_dev *dev = to_mdev(entry->ucontext->device);
 	struct mlx5_var_table *var_table = &dev->var_table;
-	struct mlx5_ib_dm *mdm;

 	switch (mentry->mmap_flag) {
 	case MLX5_IB_MMAP_TYPE_MEMIC:
-		mdm = container_of(mentry, struct mlx5_ib_dm, mentry);
-		mlx5_cmd_dealloc_memic(&dev->dm, mdm->dev_addr,
-				       mdm->size);
-		kfree(mdm);
+	case MLX5_IB_MMAP_TYPE_MEMIC_OP:
+		mlx5_ib_dm_mmap_free(dev, mentry);
 		break;
 	case MLX5_IB_MMAP_TYPE_VAR:
 		mutex_lock(&var_table->bitmap_lock);
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index ae971de6e934..b714131f87b7 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -166,6 +166,7 @@  enum mlx5_ib_mmap_type {
 	MLX5_IB_MMAP_TYPE_VAR = 2,
 	MLX5_IB_MMAP_TYPE_UAR_WC = 3,
 	MLX5_IB_MMAP_TYPE_UAR_NC = 4,
+	MLX5_IB_MMAP_TYPE_MEMIC_OP = 5,
 };

 struct mlx5_bfreg_info {
@@ -618,18 +619,30 @@  struct mlx5_user_mmap_entry {
 	u32 page_idx;
 };

+struct mlx5_ib_dm_op_entry {
+	struct mlx5_user_mmap_entry	mentry;
+	phys_addr_t			op_addr;
+	struct mlx5_ib_dm		*dm;
+	u8				op;
+};
+
 struct mlx5_ib_dm {
 	struct ib_dm		ibdm;
 	phys_addr_t		dev_addr;
 	u32			type;
 	size_t			size;
 	union {
+		struct {
+				struct mlx5_user_mmap_entry mentry;
+				struct xarray		ops;
+				struct mutex		ops_xa_lock;
+				struct kref		ref;
+		} memic;
 		struct {
 			u32	obj_id;
 		} icm_dm;
 		/* other dm types specific params should be added here */
 	};
-	struct mlx5_user_mmap_entry mentry;
 };

 #define MLX5_IB_MTT_PRESENT (MLX5_IB_MTT_READ | MLX5_IB_MTT_WRITE)
@@ -1352,6 +1365,7 @@  struct ib_dm *mlx5_ib_alloc_dm(struct ib_device *ibdev,
 			       struct ib_dm_alloc_attr *attr,
 			       struct uverbs_attr_bundle *attrs);
 int mlx5_ib_dealloc_dm(struct ib_dm *ibdm, struct uverbs_attr_bundle *attrs);
+void mlx5_ib_dm_memic_free(struct kref *kref);
 struct ib_mr *mlx5_ib_reg_dm_mr(struct ib_pd *pd, struct ib_dm *dm,
 				struct ib_dm_mr_attr *attr,
 				struct uverbs_attr_bundle *attrs);
diff --git a/include/uapi/rdma/mlx5_user_ioctl_cmds.h b/include/uapi/rdma/mlx5_user_ioctl_cmds.h
index 3f0bc7597ba7..c6fbc5211717 100644
--- a/include/uapi/rdma/mlx5_user_ioctl_cmds.h
+++ b/include/uapi/rdma/mlx5_user_ioctl_cmds.h
@@ -41,6 +41,17 @@  enum mlx5_ib_create_flow_action_attrs {
 	MLX5_IB_ATTR_CREATE_FLOW_ACTION_FLAGS = (1U << UVERBS_ID_NS_SHIFT),
 };

+enum mlx5_ib_dm_methods {
+	MLX5_IB_METHOD_DM_MAP_OP_ADDR  = (1U << UVERBS_ID_NS_SHIFT),
+};
+
+enum mlx5_ib_dm_map_op_addr_attrs {
+	MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_HANDLE = (1U << UVERBS_ID_NS_SHIFT),
+	MLX5_IB_ATTR_DM_MAP_OP_ADDR_REQ_OP,
+	MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_START_OFFSET,
+	MLX5_IB_ATTR_DM_MAP_OP_ADDR_RESP_PAGE_INDEX,
+};
+
 enum mlx5_ib_alloc_dm_attrs {
 	MLX5_IB_ATTR_ALLOC_DM_RESP_START_OFFSET = (1U << UVERBS_ID_NS_SHIFT),
 	MLX5_IB_ATTR_ALLOC_DM_RESP_PAGE_INDEX,