[rdma-core,v7,4/6] pyverbs: Add dma-buf based MR support

Commit Message

Xiong, Jianxin Jan. 25, 2021, 7:57 p.m. UTC

Define a new sub-class of 'MR' that uses dma-buf object for the memory
region. Define a new class 'DmaBuf' as a wrapper for dma-buf allocation
mechanism implemented in C.

Update the cmake function for cython modules to allow building modules
with mixed cython and c source files.

Signed-off-by: Jianxin Xiong <[e-mail]>
---
 buildlib/pyverbs_functions.cmake |  78 +++++++----
 pyverbs/CMakeLists.txt           |  11 +-
 pyverbs/dmabuf.pxd               |  15 +++
 pyverbs/dmabuf.pyx               |  73 ++++++++++
 pyverbs/dmabuf_alloc.c           | 278 +++++++++++++++++++++++++++++++++++++++
 pyverbs/dmabuf_alloc.h           |  19 +++
 pyverbs/libibverbs.pxd           |   2 +
 pyverbs/mr.pxd                   |   6 +
 pyverbs/mr.pyx                   | 105 ++++++++++++++-
 9 files changed, 557 insertions(+), 30 deletions(-)
 create mode 100644 pyverbs/dmabuf.pxd
 create mode 100644 pyverbs/dmabuf.pyx
 create mode 100644 pyverbs/dmabuf_alloc.c
 create mode 100644 pyverbs/dmabuf_alloc.h

Comments

Gal Pressman Jan. 31, 2021, 3:31 p.m. UTC | #1

On 25/01/2021 21:57, Jianxin Xiong wrote:
> Define a new sub-class of 'MR' that uses dma-buf object for the memory
> region. Define a new class 'DmaBuf' as a wrapper for dma-buf allocation
> mechanism implemented in C.
> 
> Update the cmake function for cython modules to allow building modules
> with mixed cython and c source files.
> 
> Signed-off-by: Jianxin Xiong <[e-mail]>
> ---
>  buildlib/pyverbs_functions.cmake |  78 +++++++----
>  pyverbs/CMakeLists.txt           |  11 +-
>  pyverbs/dmabuf.pxd               |  15 +++
>  pyverbs/dmabuf.pyx               |  73 ++++++++++
>  pyverbs/dmabuf_alloc.c           | 278 +++++++++++++++++++++++++++++++++++++++
>  pyverbs/dmabuf_alloc.h           |  19 +++
>  pyverbs/libibverbs.pxd           |   2 +
>  pyverbs/mr.pxd                   |   6 +
>  pyverbs/mr.pyx                   | 105 ++++++++++++++-
>  9 files changed, 557 insertions(+), 30 deletions(-)
>  create mode 100644 pyverbs/dmabuf.pxd
>  create mode 100644 pyverbs/dmabuf.pyx
>  create mode 100644 pyverbs/dmabuf_alloc.c
>  create mode 100644 pyverbs/dmabuf_alloc.h
> 
> diff --git a/buildlib/pyverbs_functions.cmake b/buildlib/pyverbs_functions.cmake
> index 953cec2..0792410 100644
> --- a/buildlib/pyverbs_functions.cmake
> +++ b/buildlib/pyverbs_functions.cmake
> @@ -1,35 +1,61 @@
>  # SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
>  # Copyright (c) 2018, Mellanox Technologies. All rights reserved.  See COPYING file
> +# Copyright (c) 2020, Intel Corporation. All rights reserved.  See COPYING file
> +
> +function(build_module_from_cfiles PY_MODULE MODULE_NAME ALL_CFILES LINKER_FLAGS)
> +  string(REGEX REPLACE "\\.so$" "" SONAME "${MODULE_NAME}${CMAKE_PYTHON_SO_SUFFIX}")
> +  add_library(${SONAME} SHARED ${ALL_CFILES})
> +  set_target_properties(${SONAME} PROPERTIES
> +    COMPILE_FLAGS "${CMAKE_C_FLAGS} -fPIC -fno-strict-aliasing -Wno-unused-function -Wno-redundant-decls -Wno-shadow -Wno-cast-function-type -Wno-implicit-fallthrough -Wno-unknown-warning -Wno-unknown-warning-option -Wno-deprecated-declarations ${NO_VAR_TRACKING_FLAGS}"
> +    LIBRARY_OUTPUT_DIRECTORY "${BUILD_PYTHON}/${PY_MODULE}"
> +    PREFIX "")
> +  target_link_libraries(${SONAME} LINK_PRIVATE ${PYTHON_LIBRARIES} ibverbs rdmacm ${LINKER_FLAGS})
> +  install(TARGETS ${SONAME}
> +    DESTINATION ${CMAKE_INSTALL_PYTHON_ARCH_LIB}/${PY_MODULE})
> +endfunction()
>  
>  function(rdma_cython_module PY_MODULE LINKER_FLAGS)
> -  foreach(PYX_FILE ${ARGN})
> -    get_filename_component(FILENAME ${PYX_FILE} NAME_WE)
> -    get_filename_component(DIR ${PYX_FILE} DIRECTORY)
> -	if (DIR)
> -		set(PYX "${CMAKE_CURRENT_SOURCE_DIR}/${DIR}/${FILENAME}.pyx")
> -	else()
> -	    set(PYX "${CMAKE_CURRENT_SOURCE_DIR}/${FILENAME}.pyx")
> -	endif()
> -    set(CFILE "${CMAKE_CURRENT_BINARY_DIR}/${FILENAME}.c")
> -    include_directories(${PYTHON_INCLUDE_DIRS})
> -    add_custom_command(
> -      OUTPUT "${CFILE}"
> -      MAIN_DEPENDENCY "${PYX}"
> -      COMMAND ${CYTHON_EXECUTABLE} "${PYX}" -o "${CFILE}"
> -      "-I${PYTHON_INCLUDE_DIRS}"
> -      COMMENT "Cythonizing ${PYX}"
> +  set(ALL_CFILES "")
> +  set(MODULE_NAME "")
> +  foreach(SRC_FILE ${ARGN})
> +    get_filename_component(FILENAME ${SRC_FILE} NAME_WE)
> +    get_filename_component(DIR ${SRC_FILE} DIRECTORY)
> +    get_filename_component(EXT ${SRC_FILE} EXT)
> +    if (DIR)
> +      set(SRC_PATH "${CMAKE_CURRENT_SOURCE_DIR}/${DIR}")
> +    else()
> +      set(SRC_PATH "${CMAKE_CURRENT_SOURCE_DIR}")
> +    endif()
> +    if (${EXT} STREQUAL ".pyx")
> +      # each .pyx file starts a new module, finish the previous module first
> +      if (ALL_CFILES AND MODULE_NAME)
> +        build_module_from_cfiles(${PY_MODULE} ${MODULE_NAME} "${ALL_CFILES}" "${LINKER_FLAGS}")
> +      endif()
> +      set(PYX "${SRC_PATH}/${FILENAME}.pyx")
> +      set(CFILE "${CMAKE_CURRENT_BINARY_DIR}/${FILENAME}.c")
> +      include_directories(${PYTHON_INCLUDE_DIRS})
> +      add_custom_command(
> +        OUTPUT "${CFILE}"
> +        MAIN_DEPENDENCY "${PYX}"
> +        COMMAND ${CYTHON_EXECUTABLE} "${PYX}" -o "${CFILE}"
> +        "-I${PYTHON_INCLUDE_DIRS}"
> +        COMMENT "Cythonizing ${PYX}"
>        )
> -
> -    string(REGEX REPLACE "\\.so$" "" SONAME "${FILENAME}${CMAKE_PYTHON_SO_SUFFIX}")
> -    add_library(${SONAME} SHARED ${CFILE})
> -    set_target_properties(${SONAME} PROPERTIES
> -      COMPILE_FLAGS "${CMAKE_C_FLAGS} -fPIC -fno-strict-aliasing -Wno-unused-function -Wno-redundant-decls -Wno-shadow -Wno-cast-function-type -Wno-implicit-fallthrough -Wno-unknown-warning -Wno-unknown-warning-option -Wno-deprecated-declarations ${NO_VAR_TRACKING_FLAGS}"
> -      LIBRARY_OUTPUT_DIRECTORY "${BUILD_PYTHON}/${PY_MODULE}"
> -      PREFIX "")
> -    target_link_libraries(${SONAME} LINK_PRIVATE ${PYTHON_LIBRARIES} ibverbs rdmacm ${LINKER_FLAGS})
> -    install(TARGETS ${SONAME}
> -      DESTINATION ${CMAKE_INSTALL_PYTHON_ARCH_LIB}/${PY_MODULE})
> +      set(MODULE_NAME ${FILENAME})
> +      set(ALL_CFILES "${CFILE}")
> +    elseif(${EXT} STREQUAL ".c")
> +      # .c files belong to the same module as the most recent .pyx file,
> +      # ignored if appearing before all .pyx files
> +      set(CFILE "${SRC_PATH}/${FILENAME}.c")
> +      set(ALL_CFILES "${ALL_CFILES};${CFILE}")
> +    else()
> +      continue()
> +    endif()
>    endforeach()
> +  # finish the last module
> +  if (ALL_CFILES AND MODULE_NAME)
> +    build_module_from_cfiles(${PY_MODULE} ${MODULE_NAME} "${ALL_CFILES}" "${LINKER_FLAGS}")
> +  endif()
>  endfunction()
>  
>  function(rdma_python_module PY_MODULE)
> diff --git a/pyverbs/CMakeLists.txt b/pyverbs/CMakeLists.txt
> index 9542c4b..6fd7625 100644
> --- a/pyverbs/CMakeLists.txt
> +++ b/pyverbs/CMakeLists.txt
> @@ -1,5 +1,10 @@
>  # SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
>  # Copyright (c) 2019, Mellanox Technologies. All rights reserved. See COPYING file
> +# Copyright (c) 2020, Intel Corporation. All rights reserved. See COPYING file
> +
> +publish_internal_headers(""
> +  dmabuf_alloc.h
> +)
>  
>  rdma_cython_module(pyverbs ""
>    addr.pyx
> @@ -8,15 +13,17 @@ rdma_cython_module(pyverbs ""
>    cmid.pyx
>    cq.pyx
>    device.pyx
> +  dmabuf.pyx
> +  dmabuf_alloc.c
>    enums.pyx
>    mem_alloc.pyx
>    mr.pyx
>    pd.pyx
>    qp.pyx
> +  srq.pyx
>    wr.pyx
>    xrcd.pyx
> -  srq.pyx
> -  )
> +)
>  
>  rdma_python_module(pyverbs
>    __init__.py
> diff --git a/pyverbs/dmabuf.pxd b/pyverbs/dmabuf.pxd
> new file mode 100644
> index 0000000..a063acb
> --- /dev/null
> +++ b/pyverbs/dmabuf.pxd
> @@ -0,0 +1,15 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
> +# Copyright (c) 2020, Intel Corporation. All rights reserved. See COPYING file
> +
> +#cython: language_level=3
> +
> +cdef class DmaBuf:
> +    cdef int drm_fd
> +    cdef int handle
> +    cdef int fd
> +    cdef unsigned long size
> +    cdef unsigned long map_offset
> +    cdef void *dmabuf
> +    cdef object dmabuf_mrs
> +    cdef add_ref(self, obj)
> +    cpdef close(self)
> diff --git a/pyverbs/dmabuf.pyx b/pyverbs/dmabuf.pyx
> new file mode 100644
> index 0000000..b9406bd
> --- /dev/null
> +++ b/pyverbs/dmabuf.pyx
> @@ -0,0 +1,73 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
> +# Copyright (c) 2020, Intel Corporation. All rights reserved. See COPYING file
> +
> +#cython: language_level=3
> +
> +import weakref
> +
> +from pyverbs.base cimport close_weakrefs
> +from pyverbs.base import PyverbsRDMAErrno
> +from pyverbs.mr cimport DmaBufMR
> +
> +cdef extern from "dmabuf_alloc.h":
> +    cdef struct dmabuf:
> +        pass
> +    dmabuf *dmabuf_alloc(unsigned long size, int unit, int gtt)
> +    void dmabuf_free(dmabuf *dmabuf)
> +    int dmabuf_get_drm_fd(dmabuf *dmabuf)
> +    int dmabuf_get_fd(dmabuf *dmabuf)
> +    unsigned long dmabuf_get_offset(dmabuf *dmabuf)
> +
> +
> +cdef class DmaBuf:
> +    def __init__(self, size, unit=0, gtt=0):
> +        """
> +        Allocate DmaBuf object from a GPU device. This is done through the
> +        DRI device interface. Usually this requires the effective user id
> +        being a member of the 'render' group.
> +        :param size: The size (in number of bytes) of the buffer.
> +        :param unit: The unit number of the GPU to allocate the buffer from.
> +        :param gtt: Allocate from GTT instead of VRAM.
> +        :return: The newly created DmaBuf object on success.
> +        """
> +        self.dmabuf_mrs = weakref.WeakSet()
> +        self.dmabuf = dmabuf_alloc(size, unit, gtt)
> +        if self.dmabuf == NULL:
> +            raise PyverbsRDMAErrno(f'Failed to allocate dmabuf of size {size} on unit {unit}')
> +        self.drm_fd = dmabuf_get_drm_fd(<dmabuf *>self.dmabuf)
> +        self.fd = dmabuf_get_fd(<dmabuf *>self.dmabuf)
> +        self.map_offset = dmabuf_get_offset(<dmabuf *>self.dmabuf)
> +
> +    def __dealloc__(self):
> +        self.close()
> +
> +    cpdef close(self):
> +        if self.dmabuf == NULL:
> +            return None
> +        close_weakrefs([self.dmabuf_mrs])
> +        dmabuf_free(<dmabuf *>self.dmabuf)
> +        self.dmabuf = NULL
> +
> +    cdef add_ref(self, obj):
> +        if isinstance(obj, DmaBufMR):
> +            self.dmabuf_mrs.add(obj)
> +
> +    @property
> +    def drm_fd(self):
> +        return self.drm_fd
> +
> +    @property
> +    def handle(self):
> +        return self.handle
> +
> +    @property
> +    def fd(self):
> +        return self.fd
> +
> +    @property
> +    def size(self):
> +        return self.size
> +
> +    @property
> +    def map_offset(self):
> +        return self.map_offset
> diff --git a/pyverbs/dmabuf_alloc.c b/pyverbs/dmabuf_alloc.c
> new file mode 100644
> index 0000000..05eae75
> --- /dev/null
> +++ b/pyverbs/dmabuf_alloc.c
> @@ -0,0 +1,278 @@
> +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> +/*
> + * Copyright 2020 Intel Corporation. All rights reserved. See COPYING file
> + */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <unistd.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <drm/drm.h>
> +#include <drm/i915_drm.h>
> +#include <drm/amdgpu_drm.h>
> +#include <drm/radeon_drm.h>

I assume these should come from the kernel headers package, right?
We're getting new compilation errors on SLES 15 for some reason, although the
package is installed.

FAILED: pyverbs/CMakeFiles/dmabuf.cpython-36m-x86_64-linux-gnu.dir/dmabuf_alloc.c.o 
/usr/bin/cc -Ddmabuf_cpython_36m_x86_64_linux_gnu_EXPORTS -Iinclude -I/usr/include/libnl3 -I/usr/include/python3.6m -Wall -Wextra -Wno-sign-compare -Wno-unused-parameter -Wmissing-prototypes -Wmissing-declarations -Wwrite-strings -Wformat=2 -Wformat-nonliteral -Wdate-time -Wnested-externs -Wshadow -Wstrict-prototypes -Wold-style-definition -Wredundant-decls -O2 -g  -fPIC    -Wall -Wextra -Wno-sign-compare -Wno-unused-parameter -Wmissing-prototypes -Wmissing-declarations -Wwrite-strings -Wformat=2 -Wformat-nonliteral -Wdate-time -Wnested-externs -Wshadow -Wstrict-prototypes -Wold-style-definition -Wredundant-decls -fPIC -fno-strict-aliasing -Wno-unused-function -Wno-redundant-decls -Wno-shadow -Wno-cast-function-type -Wno-implicit-fallthrough -Wno-unknown-warning -Wno-unknown-warning-option -Wno-deprecated-declarations  -fno-var-tracking-assignments -std=gnu11 -MD -MT pyverbs/CMakeFiles/dmabuf.cpython-36m-x86_64-linux-gnu.dir/dmabuf_alloc.c.o -MF pyverbs/CMakeFiles/dmabuf.cpython-36m-x86_64-linux-gnu.dir/dmabuf_alloc.c.o.d -o pyverbs/CMakeFiles/dmabuf.cpython-36m-x86_64-linux-gnu.dir/dmabuf_alloc.c.o   -c ../pyverbs/dmabuf_alloc.c
 ../pyverbs/dmabuf_alloc.c:12:10: fatal error: drm/drm.h: No such file or directory
  #include <drm/drm.h>
           ^~~~~~~~~~~
 compilation terminated.

Leon Romanovsky Feb. 1, 2021, 6:16 a.m. UTC | #2

On Sun, Jan 31, 2021 at 05:31:16PM +0200, Gal Pressman wrote:
> On 25/01/2021 21:57, Jianxin Xiong wrote:
> > Define a new sub-class of 'MR' that uses dma-buf object for the memory
> > region. Define a new class 'DmaBuf' as a wrapper for dma-buf allocation
> > mechanism implemented in C.
> >
> > Update the cmake function for cython modules to allow building modules
> > with mixed cython and c source files.
> >
> > Signed-off-by: Jianxin Xiong <[e-mail]>
> > ---
> >  buildlib/pyverbs_functions.cmake |  78 +++++++----
> >  pyverbs/CMakeLists.txt           |  11 +-
> >  pyverbs/dmabuf.pxd               |  15 +++
> >  pyverbs/dmabuf.pyx               |  73 ++++++++++
> >  pyverbs/dmabuf_alloc.c           | 278 +++++++++++++++++++++++++++++++++++++++
> >  pyverbs/dmabuf_alloc.h           |  19 +++
> >  pyverbs/libibverbs.pxd           |   2 +
> >  pyverbs/mr.pxd                   |   6 +
> >  pyverbs/mr.pyx                   | 105 ++++++++++++++-
> >  9 files changed, 557 insertions(+), 30 deletions(-)
> >  create mode 100644 pyverbs/dmabuf.pxd
> >  create mode 100644 pyverbs/dmabuf.pyx
> >  create mode 100644 pyverbs/dmabuf_alloc.c
> >  create mode 100644 pyverbs/dmabuf_alloc.h

<...>

> > index 0000000..05eae75
> > --- /dev/null
> > +++ b/pyverbs/dmabuf_alloc.c
> > @@ -0,0 +1,278 @@
> > +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> > +/*
> > + * Copyright 2020 Intel Corporation. All rights reserved. See COPYING file
> > + */
> > +
> > +#include <stdio.h>
> > +#include <stdlib.h>
> > +#include <stdint.h>
> > +#include <unistd.h>
> > +#include <string.h>
> > +#include <errno.h>
> > +#include <drm/drm.h>
> > +#include <drm/i915_drm.h>
> > +#include <drm/amdgpu_drm.h>
> > +#include <drm/radeon_drm.h>
>
> I assume these should come from the kernel headers package, right?

This is gross, all kernel headers should be placed in kernel-headers/*
and "update" script needs to be extended to take drm/* files too :(.

Jianxin, are you fixing it?

Thanks

Daniel Vetter Feb. 1, 2021, 2:10 p.m. UTC | #3

On Mon, Feb 1, 2021 at 7:16 AM Leon Romanovsky <[e-mail]> wrote:
>
> On Sun, Jan 31, 2021 at 05:31:16PM +0200, Gal Pressman wrote:
> > On 25/01/2021 21:57, Jianxin Xiong wrote:
> > > Define a new sub-class of 'MR' that uses dma-buf object for the memory
> > > region. Define a new class 'DmaBuf' as a wrapper for dma-buf allocation
> > > mechanism implemented in C.
> > >
> > > Update the cmake function for cython modules to allow building modules
> > > with mixed cython and c source files.
> > >
> > > Signed-off-by: Jianxin Xiong <[e-mail]>
> > > ---
> > >  buildlib/pyverbs_functions.cmake |  78 +++++++----
> > >  pyverbs/CMakeLists.txt           |  11 +-
> > >  pyverbs/dmabuf.pxd               |  15 +++
> > >  pyverbs/dmabuf.pyx               |  73 ++++++++++
> > >  pyverbs/dmabuf_alloc.c           | 278 +++++++++++++++++++++++++++++++++++++++
> > >  pyverbs/dmabuf_alloc.h           |  19 +++
> > >  pyverbs/libibverbs.pxd           |   2 +
> > >  pyverbs/mr.pxd                   |   6 +
> > >  pyverbs/mr.pyx                   | 105 ++++++++++++++-
> > >  9 files changed, 557 insertions(+), 30 deletions(-)
> > >  create mode 100644 pyverbs/dmabuf.pxd
> > >  create mode 100644 pyverbs/dmabuf.pyx
> > >  create mode 100644 pyverbs/dmabuf_alloc.c
> > >  create mode 100644 pyverbs/dmabuf_alloc.h
>
> <...>
>
> > > index 0000000..05eae75
> > > --- /dev/null
> > > +++ b/pyverbs/dmabuf_alloc.c
> > > @@ -0,0 +1,278 @@
> > > +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> > > +/*
> > > + * Copyright 2020 Intel Corporation. All rights reserved. See COPYING file
> > > + */
> > > +
> > > +#include <stdio.h>
> > > +#include <stdlib.h>
> > > +#include <stdint.h>
> > > +#include <unistd.h>
> > > +#include <string.h>
> > > +#include <errno.h>
> > > +#include <drm/drm.h>
> > > +#include <drm/i915_drm.h>
> > > +#include <drm/amdgpu_drm.h>
> > > +#include <drm/radeon_drm.h>
> >
> > I assume these should come from the kernel headers package, right?
>
> This is gross, all kernel headers should be placed in kernel-headers/*
> and "update" script needs to be extended to take drm/* files too :(.

drm kernel headers are in the libdrm package. You need that anyway for
doing the ioctls (if you don't hand-roll the restarting yourself).

Also our userspace has gone over to just outright copying the driver
headers. Not the generic headers, but for the rendering side of gpus,
which is the topic here, there's really not much generic stuff.

> Jianxin, are you fixing it?

So fix is either to depend upon libdrm for building, or have copies of
the headers included in the package for the i915/amdgpu/radeon headers
(drm/drm.h probably not so good idea).

Cheers, Daniel
>
> Thanks
> _______________________________________________
> dri-devel mailing list
> [e-mail]
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

Jason Gunthorpe Feb. 1, 2021, 3:29 p.m. UTC | #4

On Mon, Feb 01, 2021 at 03:10:00PM +0100, Daniel Vetter wrote:
> On Mon, Feb 1, 2021 at 7:16 AM Leon Romanovsky <[e-mail]> wrote:
> >
> > On Sun, Jan 31, 2021 at 05:31:16PM +0200, Gal Pressman wrote:
> > > On 25/01/2021 21:57, Jianxin Xiong wrote:
> > > > Define a new sub-class of 'MR' that uses dma-buf object for the memory
> > > > region. Define a new class 'DmaBuf' as a wrapper for dma-buf allocation
> > > > mechanism implemented in C.
> > > >
> > > > Update the cmake function for cython modules to allow building modules
> > > > with mixed cython and c source files.
> > > >
> > > > Signed-off-by: Jianxin Xiong <[e-mail]>
> > > >  buildlib/pyverbs_functions.cmake |  78 +++++++----
> > > >  pyverbs/CMakeLists.txt           |  11 +-
> > > >  pyverbs/dmabuf.pxd               |  15 +++
> > > >  pyverbs/dmabuf.pyx               |  73 ++++++++++
> > > >  pyverbs/dmabuf_alloc.c           | 278 +++++++++++++++++++++++++++++++++++++++
> > > >  pyverbs/dmabuf_alloc.h           |  19 +++
> > > >  pyverbs/libibverbs.pxd           |   2 +
> > > >  pyverbs/mr.pxd                   |   6 +
> > > >  pyverbs/mr.pyx                   | 105 ++++++++++++++-
> > > >  9 files changed, 557 insertions(+), 30 deletions(-)
> > > >  create mode 100644 pyverbs/dmabuf.pxd
> > > >  create mode 100644 pyverbs/dmabuf.pyx
> > > >  create mode 100644 pyverbs/dmabuf_alloc.c
> > > >  create mode 100644 pyverbs/dmabuf_alloc.h
> >
> > <...>
> >
> > > > index 0000000..05eae75
> > > > +++ b/pyverbs/dmabuf_alloc.c
> > > > @@ -0,0 +1,278 @@
> > > > +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> > > > +/*
> > > > + * Copyright 2020 Intel Corporation. All rights reserved. See COPYING file
> > > > + */
> > > > +
> > > > +#include <stdio.h>
> > > > +#include <stdlib.h>
> > > > +#include <stdint.h>
> > > > +#include <unistd.h>
> > > > +#include <string.h>
> > > > +#include <errno.h>
> > > > +#include <drm/drm.h>
> > > > +#include <drm/i915_drm.h>
> > > > +#include <drm/amdgpu_drm.h>
> > > > +#include <drm/radeon_drm.h>
> > >
> > > I assume these should come from the kernel headers package, right?
> >
> > This is gross, all kernel headers should be placed in kernel-headers/*
> > and "update" script needs to be extended to take drm/* files too :(.
> 
> drm kernel headers are in the libdrm package. You need that anyway for
> doing the ioctls (if you don't hand-roll the restarting yourself).
> 
> Also our userspace has gone over to just outright copying the driver
> headers. Not the generic headers, but for the rendering side of gpus,
> which is the topic here, there's really not much generic stuff.
> 
> > Jianxin, are you fixing it?
> 
> So fix is either to depend upon libdrm for building, or have copies of
> the headers included in the package for the i915/amdgpu/radeon headers
> (drm/drm.h probably not so good idea).

We should have a cmake test to not build the drm parts if it can't be
built, and pyverbs should skip the tests.

Jason

Xiong, Jianxin Feb. 1, 2021, 5:03 p.m. UTC | #5

> -----Original Message-----
> From: Jason Gunthorpe <[e-mail]>
> Sent: Monday, February 01, 2021 7:29 AM
> To: Daniel Vetter <[e-mail]>
> Cc: Leon Romanovsky <[e-mail]>; Gal Pressman <[e-mail]>; Xiong, Jianxin <[e-mail]>; Yishai Hadas
> <[e-mail]>; linux-rdma <[e-mail]>; Edward Srouji <[e-mail]>; dri-devel <dri-
> [e-mail]>; Christian Koenig <[e-mail]>; Doug Ledford <[e-mail]>; Vetter, Daniel
> <[e-mail]>
> Subject: Re: [PATCH rdma-core v7 4/6] pyverbs: Add dma-buf based MR support
> 
> On Mon, Feb 01, 2021 at 03:10:00PM +0100, Daniel Vetter wrote:
> > On Mon, Feb 1, 2021 at 7:16 AM Leon Romanovsky <[e-mail]> wrote:
> > >
> > > On Sun, Jan 31, 2021 at 05:31:16PM +0200, Gal Pressman wrote:
> > > > On 25/01/2021 21:57, Jianxin Xiong wrote:
> > > > > Define a new sub-class of 'MR' that uses dma-buf object for the
> > > > > memory region. Define a new class 'DmaBuf' as a wrapper for
> > > > > dma-buf allocation mechanism implemented in C.
> > > > >
> > > > > Update the cmake function for cython modules to allow building
> > > > > modules with mixed cython and c source files.
> > > > >
> > > > > Signed-off-by: Jianxin Xiong <[e-mail]>
> > > > > buildlib/pyverbs_functions.cmake |  78 +++++++----
> > > > >  pyverbs/CMakeLists.txt           |  11 +-
> > > > >  pyverbs/dmabuf.pxd               |  15 +++
> > > > >  pyverbs/dmabuf.pyx               |  73 ++++++++++
> > > > >  pyverbs/dmabuf_alloc.c           | 278 +++++++++++++++++++++++++++++++++++++++
> > > > >  pyverbs/dmabuf_alloc.h           |  19 +++
> > > > >  pyverbs/libibverbs.pxd           |   2 +
> > > > >  pyverbs/mr.pxd                   |   6 +
> > > > >  pyverbs/mr.pyx                   | 105 ++++++++++++++-
> > > > >  9 files changed, 557 insertions(+), 30 deletions(-)  create
> > > > > mode 100644 pyverbs/dmabuf.pxd  create mode 100644
> > > > > pyverbs/dmabuf.pyx  create mode 100644 pyverbs/dmabuf_alloc.c
> > > > > create mode 100644 pyverbs/dmabuf_alloc.h
> > >
> > > <...>
> > >
> > > > > index 0000000..05eae75
> > > > > +++ b/pyverbs/dmabuf_alloc.c
> > > > > @@ -0,0 +1,278 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> > > > > +/*
> > > > > + * Copyright 2020 Intel Corporation. All rights reserved. See
> > > > > +COPYING file  */
> > > > > +
> > > > > +#include <stdio.h>
> > > > > +#include <stdlib.h>
> > > > > +#include <stdint.h>
> > > > > +#include <unistd.h>
> > > > > +#include <string.h>
> > > > > +#include <errno.h>
> > > > > +#include <drm/drm.h>
> > > > > +#include <drm/i915_drm.h>
> > > > > +#include <drm/amdgpu_drm.h>
> > > > > +#include <drm/radeon_drm.h>
> > > >
> > > > I assume these should come from the kernel headers package, right?
> > >
> > > This is gross, all kernel headers should be placed in
> > > kernel-headers/* and "update" script needs to be extended to take drm/* files too :(.
> >
> > drm kernel headers are in the libdrm package. You need that anyway for
> > doing the ioctls (if you don't hand-roll the restarting yourself).
> >
> > Also our userspace has gone over to just outright copying the driver
> > headers. Not the generic headers, but for the rendering side of gpus,
> > which is the topic here, there's really not much generic stuff.
> >
> > > Jianxin, are you fixing it?
> >
> > So fix is either to depend upon libdrm for building, or have copies of
> > the headers included in the package for the i915/amdgpu/radeon headers
> > (drm/drm.h probably not so good idea).
> 
> We should have a cmake test to not build the drm parts if it can't be built, and pyverbs should skip the tests.
> 

Yes, I will add a test for that. Also, on SLES, the headers could be under /usr/include/libdrm instead of /usr/include/drm. The make test should check that and use proper path.

Daniel Vetter Feb. 2, 2021, 3:24 p.m. UTC | #6

On Mon, Feb 01, 2021 at 05:03:44PM +0000, Xiong, Jianxin wrote:
> > -----Original Message-----
> > From: Jason Gunthorpe <[e-mail]>
> > Sent: Monday, February 01, 2021 7:29 AM
> > To: Daniel Vetter <[e-mail]>
> > Cc: Leon Romanovsky <[e-mail]>; Gal Pressman <[e-mail]>; Xiong, Jianxin <[e-mail]>; Yishai Hadas
> > <[e-mail]>; linux-rdma <[e-mail]>; Edward Srouji <[e-mail]>; dri-devel <dri-
> > [e-mail]>; Christian Koenig <[e-mail]>; Doug Ledford <[e-mail]>; Vetter, Daniel
> > <[e-mail]>
> > Subject: Re: [PATCH rdma-core v7 4/6] pyverbs: Add dma-buf based MR support
> > 
> > On Mon, Feb 01, 2021 at 03:10:00PM +0100, Daniel Vetter wrote:
> > > On Mon, Feb 1, 2021 at 7:16 AM Leon Romanovsky <[e-mail]> wrote:
> > > >
> > > > On Sun, Jan 31, 2021 at 05:31:16PM +0200, Gal Pressman wrote:
> > > > > On 25/01/2021 21:57, Jianxin Xiong wrote:
> > > > > > Define a new sub-class of 'MR' that uses dma-buf object for the
> > > > > > memory region. Define a new class 'DmaBuf' as a wrapper for
> > > > > > dma-buf allocation mechanism implemented in C.
> > > > > >
> > > > > > Update the cmake function for cython modules to allow building
> > > > > > modules with mixed cython and c source files.
> > > > > >
> > > > > > Signed-off-by: Jianxin Xiong <[e-mail]>
> > > > > > buildlib/pyverbs_functions.cmake |  78 +++++++----
> > > > > >  pyverbs/CMakeLists.txt           |  11 +-
> > > > > >  pyverbs/dmabuf.pxd               |  15 +++
> > > > > >  pyverbs/dmabuf.pyx               |  73 ++++++++++
> > > > > >  pyverbs/dmabuf_alloc.c           | 278 +++++++++++++++++++++++++++++++++++++++
> > > > > >  pyverbs/dmabuf_alloc.h           |  19 +++
> > > > > >  pyverbs/libibverbs.pxd           |   2 +
> > > > > >  pyverbs/mr.pxd                   |   6 +
> > > > > >  pyverbs/mr.pyx                   | 105 ++++++++++++++-
> > > > > >  9 files changed, 557 insertions(+), 30 deletions(-)  create
> > > > > > mode 100644 pyverbs/dmabuf.pxd  create mode 100644
> > > > > > pyverbs/dmabuf.pyx  create mode 100644 pyverbs/dmabuf_alloc.c
> > > > > > create mode 100644 pyverbs/dmabuf_alloc.h
> > > >
> > > > <...>
> > > >
> > > > > > index 0000000..05eae75
> > > > > > +++ b/pyverbs/dmabuf_alloc.c
> > > > > > @@ -0,0 +1,278 @@
> > > > > > +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> > > > > > +/*
> > > > > > + * Copyright 2020 Intel Corporation. All rights reserved. See
> > > > > > +COPYING file  */
> > > > > > +
> > > > > > +#include <stdio.h>
> > > > > > +#include <stdlib.h>
> > > > > > +#include <stdint.h>
> > > > > > +#include <unistd.h>
> > > > > > +#include <string.h>
> > > > > > +#include <errno.h>
> > > > > > +#include <drm/drm.h>
> > > > > > +#include <drm/i915_drm.h>
> > > > > > +#include <drm/amdgpu_drm.h>
> > > > > > +#include <drm/radeon_drm.h>
> > > > >
> > > > > I assume these should come from the kernel headers package, right?
> > > >
> > > > This is gross, all kernel headers should be placed in
> > > > kernel-headers/* and "update" script needs to be extended to take drm/* files too :(.
> > >
> > > drm kernel headers are in the libdrm package. You need that anyway for
> > > doing the ioctls (if you don't hand-roll the restarting yourself).
> > >
> > > Also our userspace has gone over to just outright copying the driver
> > > headers. Not the generic headers, but for the rendering side of gpus,
> > > which is the topic here, there's really not much generic stuff.
> > >
> > > > Jianxin, are you fixing it?
> > >
> > > So fix is either to depend upon libdrm for building, or have copies of
> > > the headers included in the package for the i915/amdgpu/radeon headers
> > > (drm/drm.h probably not so good idea).
> > 
> > We should have a cmake test to not build the drm parts if it can't be built, and pyverbs should skip the tests.
> > 
> 
> Yes, I will add a test for that. Also, on SLES, the headers could be under /usr/include/libdrm instead of /usr/include/drm. The make test should check that and use proper path. 

Please use pkgconfig for this, libdrm installs a .pc file to make sure you
can find the right headers.
-Daniel

Leon Romanovsky Feb. 3, 2021, 6:03 a.m. UTC | #7

On Tue, Feb 02, 2021 at 04:24:45PM +0100, Daniel Vetter wrote:
> On Mon, Feb 01, 2021 at 05:03:44PM +0000, Xiong, Jianxin wrote:
> > > -----Original Message-----
> > > From: Jason Gunthorpe <[e-mail]>
> > > Sent: Monday, February 01, 2021 7:29 AM
> > > To: Daniel Vetter <[e-mail]>
> > > Cc: Leon Romanovsky <[e-mail]>; Gal Pressman <[e-mail]>; Xiong, Jianxin <[e-mail]>; Yishai Hadas
> > > <[e-mail]>; linux-rdma <[e-mail]>; Edward Srouji <[e-mail]>; dri-devel <dri-
> > > [e-mail]>; Christian Koenig <[e-mail]>; Doug Ledford <[e-mail]>; Vetter, Daniel
> > > <[e-mail]>
> > > Subject: Re: [PATCH rdma-core v7 4/6] pyverbs: Add dma-buf based MR support
> > >
> > > On Mon, Feb 01, 2021 at 03:10:00PM +0100, Daniel Vetter wrote:
> > > > On Mon, Feb 1, 2021 at 7:16 AM Leon Romanovsky <[e-mail]> wrote:
> > > > >
> > > > > On Sun, Jan 31, 2021 at 05:31:16PM +0200, Gal Pressman wrote:
> > > > > > On 25/01/2021 21:57, Jianxin Xiong wrote:
> > > > > > > Define a new sub-class of 'MR' that uses dma-buf object for the
> > > > > > > memory region. Define a new class 'DmaBuf' as a wrapper for
> > > > > > > dma-buf allocation mechanism implemented in C.
> > > > > > >
> > > > > > > Update the cmake function for cython modules to allow building
> > > > > > > modules with mixed cython and c source files.
> > > > > > >
> > > > > > > Signed-off-by: Jianxin Xiong <[e-mail]>
> > > > > > > buildlib/pyverbs_functions.cmake |  78 +++++++----
> > > > > > >  pyverbs/CMakeLists.txt           |  11 +-
> > > > > > >  pyverbs/dmabuf.pxd               |  15 +++
> > > > > > >  pyverbs/dmabuf.pyx               |  73 ++++++++++
> > > > > > >  pyverbs/dmabuf_alloc.c           | 278 +++++++++++++++++++++++++++++++++++++++
> > > > > > >  pyverbs/dmabuf_alloc.h           |  19 +++
> > > > > > >  pyverbs/libibverbs.pxd           |   2 +
> > > > > > >  pyverbs/mr.pxd                   |   6 +
> > > > > > >  pyverbs/mr.pyx                   | 105 ++++++++++++++-
> > > > > > >  9 files changed, 557 insertions(+), 30 deletions(-)  create
> > > > > > > mode 100644 pyverbs/dmabuf.pxd  create mode 100644
> > > > > > > pyverbs/dmabuf.pyx  create mode 100644 pyverbs/dmabuf_alloc.c
> > > > > > > create mode 100644 pyverbs/dmabuf_alloc.h
> > > > >
> > > > > <...>
> > > > >
> > > > > > > index 0000000..05eae75
> > > > > > > +++ b/pyverbs/dmabuf_alloc.c
> > > > > > > @@ -0,0 +1,278 @@
> > > > > > > +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> > > > > > > +/*
> > > > > > > + * Copyright 2020 Intel Corporation. All rights reserved. See
> > > > > > > +COPYING file  */
> > > > > > > +
> > > > > > > +#include <stdio.h>
> > > > > > > +#include <stdlib.h>
> > > > > > > +#include <stdint.h>
> > > > > > > +#include <unistd.h>
> > > > > > > +#include <string.h>
> > > > > > > +#include <errno.h>
> > > > > > > +#include <drm/drm.h>
> > > > > > > +#include <drm/i915_drm.h>
> > > > > > > +#include <drm/amdgpu_drm.h>
> > > > > > > +#include <drm/radeon_drm.h>
> > > > > >
> > > > > > I assume these should come from the kernel headers package, right?
> > > > >
> > > > > This is gross, all kernel headers should be placed in
> > > > > kernel-headers/* and "update" script needs to be extended to take drm/* files too :(.
> > > >
> > > > drm kernel headers are in the libdrm package. You need that anyway for
> > > > doing the ioctls (if you don't hand-roll the restarting yourself).
> > > >
> > > > Also our userspace has gone over to just outright copying the driver
> > > > headers. Not the generic headers, but for the rendering side of gpus,
> > > > which is the topic here, there's really not much generic stuff.
> > > >
> > > > > Jianxin, are you fixing it?
> > > >
> > > > So fix is either to depend upon libdrm for building, or have copies of
> > > > the headers included in the package for the i915/amdgpu/radeon headers
> > > > (drm/drm.h probably not so good idea).
> > >
> > > We should have a cmake test to not build the drm parts if it can't be built, and pyverbs should skip the tests.
> > >
> >
> > Yes, I will add a test for that. Also, on SLES, the headers could be under /usr/include/libdrm instead of /usr/include/drm. The make test should check that and use proper path.
>
> Please use pkgconfig for this, libdrm installs a .pc file to make sure you
> can find the right headers.

rdma-core uses cmake build system and in our case cmake find_library()
is preferable over pkgconfig.

Thanks

> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

Xiong, Jianxin Feb. 3, 2021, 4:57 p.m. UTC | #8

> -----Original Message-----
> From: Leon Romanovsky <[e-mail]>
> Sent: Tuesday, February 02, 2021 10:03 PM
> To: Daniel Vetter <[e-mail]>
> Cc: Xiong, Jianxin <[e-mail]>; Jason Gunthorpe <[e-mail]>; Gal Pressman <[e-mail]>; Yishai Hadas
> <[e-mail]>; linux-rdma <[e-mail]>; Edward Srouji <[e-mail]>; dri-devel <dri-
> [e-mail]>; Christian Koenig <[e-mail]>; Doug Ledford <[e-mail]>; Vetter, Daniel
> <[e-mail]>
> Subject: Re: [PATCH rdma-core v7 4/6] pyverbs: Add dma-buf based MR support
> 

<...>

> > > > > > > > +#include <drm/drm.h>
> > > > > > > > +#include <drm/i915_drm.h> #include <drm/amdgpu_drm.h>
> > > > > > > > +#include <drm/radeon_drm.h>
> > > > > > >
> > > > > > > I assume these should come from the kernel headers package, right?
> > > > > >
> > > > > > This is gross, all kernel headers should be placed in
> > > > > > kernel-headers/* and "update" script needs to be extended to take drm/* files too :(.
> > > > >
> > > > > drm kernel headers are in the libdrm package. You need that
> > > > > anyway for doing the ioctls (if you don't hand-roll the restarting yourself).
> > > > >
> > > > > Also our userspace has gone over to just outright copying the
> > > > > driver headers. Not the generic headers, but for the rendering
> > > > > side of gpus, which is the topic here, there's really not much generic stuff.
> > > > >
> > > > > > Jianxin, are you fixing it?
> > > > >
> > > > > So fix is either to depend upon libdrm for building, or have
> > > > > copies of the headers included in the package for the
> > > > > i915/amdgpu/radeon headers (drm/drm.h probably not so good idea).
> > > >
> > > > We should have a cmake test to not build the drm parts if it can't be built, and pyverbs should skip the tests.
> > > >
> > >
> > > Yes, I will add a test for that. Also, on SLES, the headers could be under /usr/include/libdrm instead of /usr/include/drm. The make test
> should check that and use proper path.
> >
> > Please use pkgconfig for this, libdrm installs a .pc file to make sure
> > you can find the right headers.
> 
> rdma-core uses cmake build system and in our case cmake find_library() is preferable over pkgconfig.

Only the headers are needed, and they could be installed via either the libdrm-devel package or the kernel-headers package. The cmake find_path() command is more suitable here.
 
> 
> Thanks
> 
> > -Daniel
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch

Daniel Vetter Feb. 3, 2021, 5:53 p.m. UTC | #9

On Wed, Feb 3, 2021 at 5:57 PM Xiong, Jianxin <[e-mail]> wrote:
>
> > -----Original Message-----
> > From: Leon Romanovsky <[e-mail]>
> > Sent: Tuesday, February 02, 2021 10:03 PM
> > To: Daniel Vetter <[e-mail]>
> > Cc: Xiong, Jianxin <[e-mail]>; Jason Gunthorpe <[e-mail]>; Gal Pressman <[e-mail]>; Yishai Hadas
> > <[e-mail]>; linux-rdma <[e-mail]>; Edward Srouji <[e-mail]>; dri-devel <dri-
> > [e-mail]>; Christian Koenig <[e-mail]>; Doug Ledford <[e-mail]>; Vetter, Daniel
> > <[e-mail]>
> > Subject: Re: [PATCH rdma-core v7 4/6] pyverbs: Add dma-buf based MR support
> >
>
> <...>
>
> > > > > > > > > +#include <drm/drm.h>
> > > > > > > > > +#include <drm/i915_drm.h> #include <drm/amdgpu_drm.h>
> > > > > > > > > +#include <drm/radeon_drm.h>
> > > > > > > >
> > > > > > > > I assume these should come from the kernel headers package, right?
> > > > > > >
> > > > > > > This is gross, all kernel headers should be placed in
> > > > > > > kernel-headers/* and "update" script needs to be extended to take drm/* files too :(.
> > > > > >
> > > > > > drm kernel headers are in the libdrm package. You need that
> > > > > > anyway for doing the ioctls (if you don't hand-roll the restarting yourself).
> > > > > >
> > > > > > Also our userspace has gone over to just outright copying the
> > > > > > driver headers. Not the generic headers, but for the rendering
> > > > > > side of gpus, which is the topic here, there's really not much generic stuff.
> > > > > >
> > > > > > > Jianxin, are you fixing it?
> > > > > >
> > > > > > So fix is either to depend upon libdrm for building, or have
> > > > > > copies of the headers included in the package for the
> > > > > > i915/amdgpu/radeon headers (drm/drm.h probably not so good idea).
> > > > >
> > > > > We should have a cmake test to not build the drm parts if it can't be built, and pyverbs should skip the tests.
> > > > >
> > > >
> > > > Yes, I will add a test for that. Also, on SLES, the headers could be under /usr/include/libdrm instead of /usr/include/drm. The make test
> > should check that and use proper path.
> > >
> > > Please use pkgconfig for this, libdrm installs a .pc file to make sure
> > > you can find the right headers.
> >
> > rdma-core uses cmake build system and in our case cmake find_library() is preferable over pkgconfig.
>
> Only the headers are needed, and they could be installed via either the libdrm-devel package or the kernel-headers package. The cmake find_path() command is more suitable here.

Except if your distro is buggy (or doesn't support any gpu drivers at
all) they will never be installed as part of kernel-headers.
-Daniel

Jason Gunthorpe Feb. 3, 2021, 5:56 p.m. UTC | #10

On Wed, Feb 03, 2021 at 06:53:19PM +0100, Daniel Vetter wrote:
> > > rdma-core uses cmake build system and in our case cmake
> > > find_library() is preferable over pkgconfig.
> >
> > Only the headers are needed, and they could be installed via
> > either the libdrm-devel package or the kernel-headers package. The
> > cmake find_path() command is more suitable here.
> 
> Except if your distro is buggy (or doesn't support any gpu drivers at
> all) they will never be installed as part of kernel-headers.

pkgconfig is OK, we use it for libnl for similar reasons, I just don't
like it to see it used gratuitously as it can cause more problems than
it solves

Jason

Xiong, Jianxin Feb. 3, 2021, 5:58 p.m. UTC | #11

> -----Original Message-----
> From: Daniel Vetter <[e-mail]>
> Sent: Wednesday, February 03, 2021 9:53 AM
> To: Xiong, Jianxin <[e-mail]>
> Cc: Leon Romanovsky <[e-mail]>; Jason Gunthorpe <[e-mail]>; Gal Pressman <[e-mail]>; Yishai Hadas
> <[e-mail]>; linux-rdma <[e-mail]>; Edward Srouji <[e-mail]>; dri-devel <dri-
> [e-mail]>; Christian Koenig <[e-mail]>; Doug Ledford <[e-mail]>; Vetter, Daniel
> <[e-mail]>
> Subject: Re: [PATCH rdma-core v7 4/6] pyverbs: Add dma-buf based MR support
> 
> On Wed, Feb 3, 2021 at 5:57 PM Xiong, Jianxin <[e-mail]> wrote:
> >
> > > -----Original Message-----
> > > From: Leon Romanovsky <[e-mail]>
> > > Sent: Tuesday, February 02, 2021 10:03 PM
> > > To: Daniel Vetter <[e-mail]>
> > > Cc: Xiong, Jianxin <[e-mail]>; Jason Gunthorpe
> > > <[e-mail]>; Gal Pressman <[e-mail]>; Yishai Hadas
> > > <[e-mail]>; linux-rdma <[e-mail]>;
> > > Edward Srouji <[e-mail]>; dri-devel <dri-
> > > [e-mail]>; Christian Koenig
> > > <[e-mail]>; Doug Ledford <[e-mail]>;
> > > Vetter, Daniel <[e-mail]>
> > > Subject: Re: [PATCH rdma-core v7 4/6] pyverbs: Add dma-buf based MR
> > > support
> > >
> >
> > <...>
> >
> > > > > > > > > > +#include <drm/drm.h>
> > > > > > > > > > +#include <drm/i915_drm.h> #include <drm/amdgpu_drm.h>
> > > > > > > > > > +#include <drm/radeon_drm.h>
> > > > > > > > >
> > > > > > > > > I assume these should come from the kernel headers package, right?
> > > > > > > >
> > > > > > > > This is gross, all kernel headers should be placed in
> > > > > > > > kernel-headers/* and "update" script needs to be extended to take drm/* files too :(.
> > > > > > >
> > > > > > > drm kernel headers are in the libdrm package. You need that
> > > > > > > anyway for doing the ioctls (if you don't hand-roll the restarting yourself).
> > > > > > >
> > > > > > > Also our userspace has gone over to just outright copying
> > > > > > > the driver headers. Not the generic headers, but for the
> > > > > > > rendering side of gpus, which is the topic here, there's really not much generic stuff.
> > > > > > >
> > > > > > > > Jianxin, are you fixing it?
> > > > > > >
> > > > > > > So fix is either to depend upon libdrm for building, or have
> > > > > > > copies of the headers included in the package for the
> > > > > > > i915/amdgpu/radeon headers (drm/drm.h probably not so good idea).
> > > > > >
> > > > > > We should have a cmake test to not build the drm parts if it can't be built, and pyverbs should skip the tests.
> > > > > >
> > > > >
> > > > > Yes, I will add a test for that. Also, on SLES, the headers
> > > > > could be under /usr/include/libdrm instead of /usr/include/drm.
> > > > > The make test
> > > should check that and use proper path.
> > > >
> > > > Please use pkgconfig for this, libdrm installs a .pc file to make
> > > > sure you can find the right headers.
> > >
> > > rdma-core uses cmake build system and in our case cmake find_library() is preferable over pkgconfig.
> >
> > Only the headers are needed, and they could be installed via either the libdrm-devel package or the kernel-headers package. The cmake
> find_path() command is more suitable here.
> 
> Except if your distro is buggy (or doesn't support any gpu drivers at
> all) they will never be installed as part of kernel-headers.

Right, that's why we want to check for the existence of the header file (find_path() does just that) instead of the existence of the package(s).

> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

Emil Velikov Feb. 3, 2021, 6:14 p.m. UTC | #12

On Wed, 3 Feb 2021 at 17:58, Xiong, Jianxin <[e-mail]> wrote:
>
> > -----Original Message-----
> > From: Daniel Vetter <[e-mail]>
> > Sent: Wednesday, February 03, 2021 9:53 AM
> > To: Xiong, Jianxin <[e-mail]>
> > Cc: Leon Romanovsky <[e-mail]>; Jason Gunthorpe <[e-mail]>; Gal Pressman <[e-mail]>; Yishai Hadas
> > <[e-mail]>; linux-rdma <[e-mail]>; Edward Srouji <[e-mail]>; dri-devel <dri-
> > [e-mail]>; Christian Koenig <[e-mail]>; Doug Ledford <[e-mail]>; Vetter, Daniel
> > <[e-mail]>
> > Subject: Re: [PATCH rdma-core v7 4/6] pyverbs: Add dma-buf based MR support
> >
> > On Wed, Feb 3, 2021 at 5:57 PM Xiong, Jianxin <[e-mail]> wrote:
> > >
> > > > -----Original Message-----
> > > > From: Leon Romanovsky <[e-mail]>
> > > > Sent: Tuesday, February 02, 2021 10:03 PM
> > > > To: Daniel Vetter <[e-mail]>
> > > > Cc: Xiong, Jianxin <[e-mail]>; Jason Gunthorpe
> > > > <[e-mail]>; Gal Pressman <[e-mail]>; Yishai Hadas
> > > > <[e-mail]>; linux-rdma <[e-mail]>;
> > > > Edward Srouji <[e-mail]>; dri-devel <dri-
> > > > [e-mail]>; Christian Koenig
> > > > <[e-mail]>; Doug Ledford <[e-mail]>;
> > > > Vetter, Daniel <[e-mail]>
> > > > Subject: Re: [PATCH rdma-core v7 4/6] pyverbs: Add dma-buf based MR
> > > > support
> > > >
> > >
> > > <...>
> > >
> > > > > > > > > > > +#include <drm/drm.h>
> > > > > > > > > > > +#include <drm/i915_drm.h> #include <drm/amdgpu_drm.h>
> > > > > > > > > > > +#include <drm/radeon_drm.h>
> > > > > > > > > >
> > > > > > > > > > I assume these should come from the kernel headers package, right?
> > > > > > > > >
> > > > > > > > > This is gross, all kernel headers should be placed in
> > > > > > > > > kernel-headers/* and "update" script needs to be extended to take drm/* files too :(.
> > > > > > > >
> > > > > > > > drm kernel headers are in the libdrm package. You need that
> > > > > > > > anyway for doing the ioctls (if you don't hand-roll the restarting yourself).
> > > > > > > >
> > > > > > > > Also our userspace has gone over to just outright copying
> > > > > > > > the driver headers. Not the generic headers, but for the
> > > > > > > > rendering side of gpus, which is the topic here, there's really not much generic stuff.
> > > > > > > >
> > > > > > > > > Jianxin, are you fixing it?
> > > > > > > >
> > > > > > > > So fix is either to depend upon libdrm for building, or have
> > > > > > > > copies of the headers included in the package for the
> > > > > > > > i915/amdgpu/radeon headers (drm/drm.h probably not so good idea).
> > > > > > >
> > > > > > > We should have a cmake test to not build the drm parts if it can't be built, and pyverbs should skip the tests.
> > > > > > >
> > > > > >
> > > > > > Yes, I will add a test for that. Also, on SLES, the headers
> > > > > > could be under /usr/include/libdrm instead of /usr/include/drm.
> > > > > > The make test
> > > > should check that and use proper path.
> > > > >
> > > > > Please use pkgconfig for this, libdrm installs a .pc file to make
> > > > > sure you can find the right headers.
> > > >
> > > > rdma-core uses cmake build system and in our case cmake find_library() is preferable over pkgconfig.
> > >
> > > Only the headers are needed, and they could be installed via either the libdrm-devel package or the kernel-headers package. The cmake
> > find_path() command is more suitable here.
> >
> > Except if your distro is buggy (or doesn't support any gpu drivers at
> > all) they will never be installed as part of kernel-headers.
>
> Right, that's why we want to check for the existence of the header file (find_path() does just that) instead of the existence of the package(s).
>
Fwiw the .pc file does not list "packages", but the location of the
headers and/or libraries.
Last time I tried find_path() wasn't that great, since it had no way
to detect non-standard (aka outside of /usr/include) installs.

HTH
-Emil

Patch

diff --git a/buildlib/pyverbs_functions.cmake b/buildlib/pyverbs_functions.cmake
index 953cec2..0792410 100644
--- a/buildlib/pyverbs_functions.cmake
+++ b/buildlib/pyverbs_functions.cmake
@@ -1,35 +1,61 @@ 
 # SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
 # Copyright (c) 2018, Mellanox Technologies. All rights reserved.  See COPYING file
+# Copyright (c) 2020, Intel Corporation. All rights reserved.  See COPYING file
+
+function(build_module_from_cfiles PY_MODULE MODULE_NAME ALL_CFILES LINKER_FLAGS)
+  string(REGEX REPLACE "\\.so$" "" SONAME "${MODULE_NAME}${CMAKE_PYTHON_SO_SUFFIX}")
+  add_library(${SONAME} SHARED ${ALL_CFILES})
+  set_target_properties(${SONAME} PROPERTIES
+    COMPILE_FLAGS "${CMAKE_C_FLAGS} -fPIC -fno-strict-aliasing -Wno-unused-function -Wno-redundant-decls -Wno-shadow -Wno-cast-function-type -Wno-implicit-fallthrough -Wno-unknown-warning -Wno-unknown-warning-option -Wno-deprecated-declarations ${NO_VAR_TRACKING_FLAGS}"
+    LIBRARY_OUTPUT_DIRECTORY "${BUILD_PYTHON}/${PY_MODULE}"
+    PREFIX "")
+  target_link_libraries(${SONAME} LINK_PRIVATE ${PYTHON_LIBRARIES} ibverbs rdmacm ${LINKER_FLAGS})
+  install(TARGETS ${SONAME}
+    DESTINATION ${CMAKE_INSTALL_PYTHON_ARCH_LIB}/${PY_MODULE})
+endfunction()
 
 function(rdma_cython_module PY_MODULE LINKER_FLAGS)
-  foreach(PYX_FILE ${ARGN})
-    get_filename_component(FILENAME ${PYX_FILE} NAME_WE)
-    get_filename_component(DIR ${PYX_FILE} DIRECTORY)
-	if (DIR)
-		set(PYX "${CMAKE_CURRENT_SOURCE_DIR}/${DIR}/${FILENAME}.pyx")
-	else()
-	    set(PYX "${CMAKE_CURRENT_SOURCE_DIR}/${FILENAME}.pyx")
-	endif()
-    set(CFILE "${CMAKE_CURRENT_BINARY_DIR}/${FILENAME}.c")
-    include_directories(${PYTHON_INCLUDE_DIRS})
-    add_custom_command(
-      OUTPUT "${CFILE}"
-      MAIN_DEPENDENCY "${PYX}"
-      COMMAND ${CYTHON_EXECUTABLE} "${PYX}" -o "${CFILE}"
-      "-I${PYTHON_INCLUDE_DIRS}"
-      COMMENT "Cythonizing ${PYX}"
+  set(ALL_CFILES "")
+  set(MODULE_NAME "")
+  foreach(SRC_FILE ${ARGN})
+    get_filename_component(FILENAME ${SRC_FILE} NAME_WE)
+    get_filename_component(DIR ${SRC_FILE} DIRECTORY)
+    get_filename_component(EXT ${SRC_FILE} EXT)
+    if (DIR)
+      set(SRC_PATH "${CMAKE_CURRENT_SOURCE_DIR}/${DIR}")
+    else()
+      set(SRC_PATH "${CMAKE_CURRENT_SOURCE_DIR}")
+    endif()
+    if (${EXT} STREQUAL ".pyx")
+      # each .pyx file starts a new module, finish the previous module first
+      if (ALL_CFILES AND MODULE_NAME)
+        build_module_from_cfiles(${PY_MODULE} ${MODULE_NAME} "${ALL_CFILES}" "${LINKER_FLAGS}")
+      endif()
+      set(PYX "${SRC_PATH}/${FILENAME}.pyx")
+      set(CFILE "${CMAKE_CURRENT_BINARY_DIR}/${FILENAME}.c")
+      include_directories(${PYTHON_INCLUDE_DIRS})
+      add_custom_command(
+        OUTPUT "${CFILE}"
+        MAIN_DEPENDENCY "${PYX}"
+        COMMAND ${CYTHON_EXECUTABLE} "${PYX}" -o "${CFILE}"
+        "-I${PYTHON_INCLUDE_DIRS}"
+        COMMENT "Cythonizing ${PYX}"
       )
-
-    string(REGEX REPLACE "\\.so$" "" SONAME "${FILENAME}${CMAKE_PYTHON_SO_SUFFIX}")
-    add_library(${SONAME} SHARED ${CFILE})
-    set_target_properties(${SONAME} PROPERTIES
-      COMPILE_FLAGS "${CMAKE_C_FLAGS} -fPIC -fno-strict-aliasing -Wno-unused-function -Wno-redundant-decls -Wno-shadow -Wno-cast-function-type -Wno-implicit-fallthrough -Wno-unknown-warning -Wno-unknown-warning-option -Wno-deprecated-declarations ${NO_VAR_TRACKING_FLAGS}"
-      LIBRARY_OUTPUT_DIRECTORY "${BUILD_PYTHON}/${PY_MODULE}"
-      PREFIX "")
-    target_link_libraries(${SONAME} LINK_PRIVATE ${PYTHON_LIBRARIES} ibverbs rdmacm ${LINKER_FLAGS})
-    install(TARGETS ${SONAME}
-      DESTINATION ${CMAKE_INSTALL_PYTHON_ARCH_LIB}/${PY_MODULE})
+      set(MODULE_NAME ${FILENAME})
+      set(ALL_CFILES "${CFILE}")
+    elseif(${EXT} STREQUAL ".c")
+      # .c files belong to the same module as the most recent .pyx file,
+      # ignored if appearing before all .pyx files
+      set(CFILE "${SRC_PATH}/${FILENAME}.c")
+      set(ALL_CFILES "${ALL_CFILES};${CFILE}")
+    else()
+      continue()
+    endif()
   endforeach()
+  # finish the last module
+  if (ALL_CFILES AND MODULE_NAME)
+    build_module_from_cfiles(${PY_MODULE} ${MODULE_NAME} "${ALL_CFILES}" "${LINKER_FLAGS}")
+  endif()
 endfunction()
 
 function(rdma_python_module PY_MODULE)
diff --git a/pyverbs/CMakeLists.txt b/pyverbs/CMakeLists.txt
index 9542c4b..6fd7625 100644
--- a/pyverbs/CMakeLists.txt
+++ b/pyverbs/CMakeLists.txt
@@ -1,5 +1,10 @@ 
 # SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
 # Copyright (c) 2019, Mellanox Technologies. All rights reserved. See COPYING file
+# Copyright (c) 2020, Intel Corporation. All rights reserved. See COPYING file
+
+publish_internal_headers(""
+  dmabuf_alloc.h
+)
 
 rdma_cython_module(pyverbs ""
   addr.pyx
@@ -8,15 +13,17 @@  rdma_cython_module(pyverbs ""
   cmid.pyx
   cq.pyx
   device.pyx
+  dmabuf.pyx
+  dmabuf_alloc.c
   enums.pyx
   mem_alloc.pyx
   mr.pyx
   pd.pyx
   qp.pyx
+  srq.pyx
   wr.pyx
   xrcd.pyx
-  srq.pyx
-  )
+)
 
 rdma_python_module(pyverbs
   __init__.py
diff --git a/pyverbs/dmabuf.pxd b/pyverbs/dmabuf.pxd
new file mode 100644
index 0000000..a063acb
--- /dev/null
+++ b/pyverbs/dmabuf.pxd
@@ -0,0 +1,15 @@ 
+# SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
+# Copyright (c) 2020, Intel Corporation. All rights reserved. See COPYING file
+
+#cython: language_level=3
+
+cdef class DmaBuf:
+    cdef int drm_fd
+    cdef int handle
+    cdef int fd
+    cdef unsigned long size
+    cdef unsigned long map_offset
+    cdef void *dmabuf
+    cdef object dmabuf_mrs
+    cdef add_ref(self, obj)
+    cpdef close(self)
diff --git a/pyverbs/dmabuf.pyx b/pyverbs/dmabuf.pyx
new file mode 100644
index 0000000..b9406bd
--- /dev/null
+++ b/pyverbs/dmabuf.pyx
@@ -0,0 +1,73 @@ 
+# SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
+# Copyright (c) 2020, Intel Corporation. All rights reserved. See COPYING file
+
+#cython: language_level=3
+
+import weakref
+
+from pyverbs.base cimport close_weakrefs
+from pyverbs.base import PyverbsRDMAErrno
+from pyverbs.mr cimport DmaBufMR
+
+cdef extern from "dmabuf_alloc.h":
+    cdef struct dmabuf:
+        pass
+    dmabuf *dmabuf_alloc(unsigned long size, int unit, int gtt)
+    void dmabuf_free(dmabuf *dmabuf)
+    int dmabuf_get_drm_fd(dmabuf *dmabuf)
+    int dmabuf_get_fd(dmabuf *dmabuf)
+    unsigned long dmabuf_get_offset(dmabuf *dmabuf)
+
+
+cdef class DmaBuf:
+    def __init__(self, size, unit=0, gtt=0):
+        """
+        Allocate DmaBuf object from a GPU device. This is done through the
+        DRI device interface. Usually this requires the effective user id
+        being a member of the 'render' group.
+        :param size: The size (in number of bytes) of the buffer.
+        :param unit: The unit number of the GPU to allocate the buffer from.
+        :param gtt: Allocate from GTT instead of VRAM.
+        :return: The newly created DmaBuf object on success.
+        """
+        self.dmabuf_mrs = weakref.WeakSet()
+        self.dmabuf = dmabuf_alloc(size, unit, gtt)
+        if self.dmabuf == NULL:
+            raise PyverbsRDMAErrno(f'Failed to allocate dmabuf of size {size} on unit {unit}')
+        self.drm_fd = dmabuf_get_drm_fd(<dmabuf *>self.dmabuf)
+        self.fd = dmabuf_get_fd(<dmabuf *>self.dmabuf)
+        self.map_offset = dmabuf_get_offset(<dmabuf *>self.dmabuf)
+
+    def __dealloc__(self):
+        self.close()
+
+    cpdef close(self):
+        if self.dmabuf == NULL:
+            return None
+        close_weakrefs([self.dmabuf_mrs])
+        dmabuf_free(<dmabuf *>self.dmabuf)
+        self.dmabuf = NULL
+
+    cdef add_ref(self, obj):
+        if isinstance(obj, DmaBufMR):
+            self.dmabuf_mrs.add(obj)
+
+    @property
+    def drm_fd(self):
+        return self.drm_fd
+
+    @property
+    def handle(self):
+        return self.handle
+
+    @property
+    def fd(self):
+        return self.fd
+
+    @property
+    def size(self):
+        return self.size
+
+    @property
+    def map_offset(self):
+        return self.map_offset
diff --git a/pyverbs/dmabuf_alloc.c b/pyverbs/dmabuf_alloc.c
new file mode 100644
index 0000000..05eae75
--- /dev/null
+++ b/pyverbs/dmabuf_alloc.c
@@ -0,0 +1,278 @@ 
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright 2020 Intel Corporation. All rights reserved. See COPYING file
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <drm/drm.h>
+#include <drm/i915_drm.h>
+#include <drm/amdgpu_drm.h>
+#include <drm/radeon_drm.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include "dmabuf_alloc.h"
+
+/*
+ * Abstraction of the buffer allocation mechanism using the DRM interface.
+ * The interface is accessed by ioctl() calls over the '/dev/dri/renderD*'
+ * device. Successful access usually requires the effective user id being
+ * in the 'render' group.
+ */
+
+struct drm {
+	int fd;
+	int (*alloc)(struct drm *drm, uint64_t size, uint32_t *handle, int gtt);
+	int (*mmap_offset)(struct drm *drm, uint32_t handle, uint64_t *offset);
+};
+
+static int i915_alloc(struct drm *drm, uint64_t size, uint32_t *handle, int gtt)
+{
+	struct drm_i915_gem_create gem_create = {};
+	int err;
+
+	gem_create.size = size;
+	err = ioctl(drm->fd, DRM_IOCTL_I915_GEM_CREATE, &gem_create);
+	if (err)
+		return err;
+
+	*handle = gem_create.handle;
+	return 0;
+}
+
+static int amdgpu_alloc(struct drm *drm, size_t size, uint32_t *handle, int gtt)
+{
+	union drm_amdgpu_gem_create gem_create = {{}};
+	int err;
+
+	gem_create.in.bo_size = size;
+	if (gtt) {
+		gem_create.in.domains = AMDGPU_GEM_DOMAIN_GTT;
+		gem_create.in.domain_flags = AMDGPU_GEM_CREATE_CPU_GTT_USWC;
+	} else {
+		gem_create.in.domains = AMDGPU_GEM_DOMAIN_VRAM;
+		gem_create.in.domain_flags =
+			AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
+	}
+	err = ioctl(drm->fd, DRM_IOCTL_AMDGPU_GEM_CREATE, &gem_create);
+	if (err)
+		return err;
+
+	*handle = gem_create.out.handle;
+	return 0;
+}
+
+static int i915_mmap_offset(struct drm *drm, uint32_t handle, uint64_t *offset)
+{
+	struct drm_i915_gem_mmap_gtt gem_mmap = {};
+	int err;
+
+	gem_mmap.handle = handle;
+	err = ioctl(drm->fd, DRM_IOCTL_I915_GEM_MMAP_GTT, &gem_mmap);
+	if (err)
+		return err;
+
+	*offset = gem_mmap.offset;
+	return 0;
+}
+
+static int amdgpu_mmap_offset(struct drm *drm, uint32_t handle,
+			      uint64_t *offset)
+{
+	union drm_amdgpu_gem_mmap gem_mmap = {{}};
+	int err;
+
+	gem_mmap.in.handle = handle;
+	err = ioctl(drm->fd, DRM_IOCTL_AMDGPU_GEM_MMAP, &gem_mmap);
+	if (err)
+		return err;
+
+	*offset = gem_mmap.out.addr_ptr;
+	return 0;
+}
+
+static struct drm *drm_open(int unit)
+{
+	char path[32];
+	struct drm_version version = {};
+	char name[16] = {};
+	int err;
+	struct drm *drm;
+
+	drm = malloc(sizeof(*drm));
+	if (!drm)
+		return NULL;
+
+	snprintf(path, sizeof(path), "/dev/dri/renderD%d", unit + 128);
+
+	drm->fd = open(path, O_RDWR);
+	if (drm->fd < 0)
+		goto out_free;
+
+	version.name = name;
+	version.name_len = 16;
+	err = ioctl(drm->fd, DRM_IOCTL_VERSION, &version);
+	if (err)
+		goto out_close;
+
+	if (!strcmp(name, "amdgpu")) {
+		drm->alloc = amdgpu_alloc;
+		drm->mmap_offset = amdgpu_mmap_offset;
+	} else if (!strcmp(name, "i915")) {
+		drm->alloc = i915_alloc;
+		drm->mmap_offset = i915_mmap_offset;
+	} else {
+		errno = EOPNOTSUPP;
+		goto out_close;
+	}
+	return drm;
+
+out_close:
+	close(drm->fd);
+
+out_free:
+	free(drm);
+	return NULL;
+}
+
+static void drm_close(struct drm *drm)
+{
+	if (!drm || drm->fd < 0)
+		return;
+
+	close(drm->fd);
+	free(drm);
+}
+
+static void drm_free_buf(struct drm *drm, uint32_t handle)
+{
+	struct drm_gem_close close = {};
+
+	close.handle = handle;
+	ioctl(drm->fd, DRM_IOCTL_GEM_CLOSE, &close);
+}
+
+static int drm_alloc_buf(struct drm *drm, size_t size, uint32_t *handle,
+			 int *fd, int gtt)
+{
+	struct drm_prime_handle prime_handle = {};
+	int err;
+
+	if (!drm || drm->fd < 0)
+		return -EINVAL;
+
+	err = drm->alloc(drm, size, handle, gtt);
+	if (err)
+		return err;
+
+	prime_handle.handle = *handle;
+	prime_handle.flags = O_RDWR;
+	err = ioctl(drm->fd, DRM_IOCTL_PRIME_HANDLE_TO_FD, &prime_handle);
+	if (err) {
+		drm_free_buf(drm, *handle);
+		return err;
+	}
+
+	*fd = prime_handle.fd;
+	return 0;
+}
+
+static int drm_map_buf(struct drm *drm, uint32_t handle, uint64_t *offset)
+{
+	if (!drm || drm->fd < 0)
+		return -EINVAL;
+
+	return drm->mmap_offset(drm, handle, offset);
+}
+
+/*
+ * Abstraction of dmabuf object, allocated using the DRI abstraction defined
+ * above.
+ */
+
+struct dmabuf {
+	struct drm *drm;
+	int fd;
+	uint32_t handle;
+	uint64_t map_offset;
+};
+
+/*
+ * dmabuf_alloc - allocate a dmabuf from GPU
+ * @size - byte size of the buffer to allocate
+ * @unit - the GPU unit to use
+ * @gtt - if true, allocate from GTT instead of VRAM
+ */
+struct dmabuf *dmabuf_alloc(uint64_t size, int unit, int gtt)
+{
+	struct dmabuf *dmabuf;
+	int err;
+
+	dmabuf = malloc(sizeof(*dmabuf));
+	if (!dmabuf)
+		return NULL;
+
+	dmabuf->drm = drm_open(unit);
+	if (!dmabuf->drm)
+		goto out_free;
+
+	err = drm_alloc_buf(dmabuf->drm, size, &dmabuf->handle, &dmabuf->fd, gtt);
+	if (err)
+		goto out_close;
+
+	err = drm_map_buf(dmabuf->drm, dmabuf->handle, &dmabuf->map_offset);
+	if (err)
+		goto out_free_buf;
+
+	return dmabuf;
+
+out_free_buf:
+	drm_free_buf(dmabuf->drm, dmabuf->handle);
+
+out_close:
+	drm_close(dmabuf->drm);
+
+out_free:
+	free(dmabuf);
+	return NULL;
+}
+
+void dmabuf_free(struct dmabuf *dmabuf)
+{
+	if (!dmabuf)
+		return;
+
+	close(dmabuf->fd);
+	drm_free_buf(dmabuf->drm, dmabuf->handle);
+	drm_close(dmabuf->drm);
+	free(dmabuf);
+}
+
+int dmabuf_get_drm_fd(struct dmabuf *dmabuf)
+{
+	if (!dmabuf || !dmabuf->drm)
+		return -1;
+
+	return dmabuf->drm->fd;
+}
+
+int dmabuf_get_fd(struct dmabuf *dmabuf)
+{
+	if (!dmabuf)
+		return -1;
+
+	return dmabuf->fd;
+}
+
+uint64_t dmabuf_get_offset(struct dmabuf *dmabuf)
+{
+	if (!dmabuf)
+		return -1;
+
+	return dmabuf->map_offset;
+}
+
diff --git a/pyverbs/dmabuf_alloc.h b/pyverbs/dmabuf_alloc.h
new file mode 100644
index 0000000..f1b03c5
--- /dev/null
+++ b/pyverbs/dmabuf_alloc.h
@@ -0,0 +1,19 @@ 
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/*
+ * Copyright 2020 Intel Corporation. All rights reserved. See COPYING file
+ */
+
+#ifndef _DMABUF_ALLOC_H_
+#define _DMABUF_ALLOC_H_
+
+#include <stdint.h>
+
+struct dmabuf;
+
+struct dmabuf *dmabuf_alloc(uint64_t size, int unit, int gtt);
+void dmabuf_free(struct dmabuf *dmabuf);
+int dmabuf_get_drm_fd(struct dmabuf *dmabuf);
+int dmabuf_get_fd(struct dmabuf *dmabuf);
+uint64_t dmabuf_get_offset(struct dmabuf *dmabuf);
+
+#endif /* _DMABUF_ALLOC_H_ */
diff --git a/pyverbs/libibverbs.pxd b/pyverbs/libibverbs.pxd
index 5005650..d960d31 100644
--- a/pyverbs/libibverbs.pxd
+++ b/pyverbs/libibverbs.pxd
@@ -507,6 +507,8 @@  cdef extern from 'infiniband/verbs.h':
     ibv_pd *ibv_alloc_pd(ibv_context *context)
     int ibv_dealloc_pd(ibv_pd *pd)
     ibv_mr *ibv_reg_mr(ibv_pd *pd, void *addr, size_t length, int access)
+    ibv_mr *ibv_reg_dmabuf_mr(ibv_pd *pd, uint64_t offset, size_t length,
+                              uint64_t iova, int fd, int access)
     int ibv_rereg_mr(ibv_mr *mr, int flags, ibv_pd *pd, void *addr,
                      size_t length, int access)
     int ibv_dereg_mr(ibv_mr *mr)
diff --git a/pyverbs/mr.pxd b/pyverbs/mr.pxd
index ebe8ada..d9a79ff 100644
--- a/pyverbs/mr.pxd
+++ b/pyverbs/mr.pxd
@@ -1,5 +1,6 @@ 
 # SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
 # Copyright (c) 2019, Mellanox Technologies. All rights reserved. See COPYING file
+# Copyright (c) 2020, Intel Corporation. All rights reserved. See COPYING file
 
 #cython: language_level=3
 
@@ -33,3 +34,8 @@  cdef class MW(PyverbsCM):
 
 cdef class DMMR(MR):
     cdef object dm
+
+cdef class DmaBufMR(MR):
+    cdef object dmabuf
+    cdef unsigned long offset
+    cdef object is_dmabuf_internal
diff --git a/pyverbs/mr.pyx b/pyverbs/mr.pyx
index b0f106d..aad47e2 100644
--- a/pyverbs/mr.pyx
+++ b/pyverbs/mr.pyx
@@ -1,11 +1,12 @@ 
 # SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
 # Copyright (c) 2019, Mellanox Technologies. All rights reserved. See COPYING file
+# Copyright (c) 2020, Intel Corporation. All rights reserved. See COPYING file
 
 import resource
 import logging
 
 from posix.mman cimport mmap, munmap, MAP_PRIVATE, PROT_READ, PROT_WRITE, \
-    MAP_ANONYMOUS, MAP_HUGETLB
+    MAP_ANONYMOUS, MAP_HUGETLB, MAP_SHARED
 from pyverbs.pyverbs_error import PyverbsError, PyverbsRDMAError, \
     PyverbsUserError
 from libc.stdint cimport uintptr_t, SIZE_MAX
@@ -15,9 +16,10 @@  from posix.stdlib cimport posix_memalign
 from libc.string cimport memcpy, memset
 cimport pyverbs.libibverbs_enums as e
 from pyverbs.device cimport DM
-from libc.stdlib cimport free
+from libc.stdlib cimport free, malloc
 from .cmid cimport CMID
 from .pd cimport PD
+from .dmabuf cimport DmaBuf
 
 cdef extern from 'sys/mman.h':
     cdef void* MAP_FAILED
@@ -380,6 +382,105 @@  cdef class DMMR(MR):
     cpdef read(self, length, offset):
         return self.dm.copy_from_dm(offset, length)
 
+cdef class DmaBufMR(MR):
+    def __init__(self, PD pd not None, length, access, DmaBuf dmabuf=None,
+                 offset=0, unit=0, gtt=0):
+        """
+        Initializes a DmaBufMR (DMA-BUF Memory Region) of the given length
+        and access flags using the given PD and DmaBuf objects.
+        :param pd: A PD object
+        :param length: Length in bytes
+        :param access: Access flags, see ibv_access_flags enum
+        :param dmabuf: A DmaBuf object. One will be allocated if absent
+        :param offset: Byte offset from the beginning of the dma-buf
+        :param unit: GPU unit for internal dmabuf allocation
+        :param gtt: If true allocate internal dmabuf from GTT instead of VRAM
+        :return: The newly created DMABUFMR
+        """
+        self.logger = logging.getLogger(self.__class__.__name__)
+        if dmabuf is None:
+            self.is_dmabuf_internal = True
+            dmabuf = DmaBuf(length + offset, unit, gtt)
+        self.mr = v.ibv_reg_dmabuf_mr(pd.pd, offset, length, offset, dmabuf.fd, access)
+        if self.mr == NULL:
+            raise PyverbsRDMAErrno(f'Failed to register a dma-buf MR. length: {length}, access flags: {access}')
+        super().__init__(pd, length, access)
+        self.pd = pd
+        self.dmabuf = dmabuf
+        self.offset = offset
+        pd.add_ref(self)
+        dmabuf.add_ref(self)
+        self.logger.debug(f'Registered dma-buf ibv_mr. Length: {length}, access flags {access}')
+
+    def __dealloc__(self):
+        self.close()
+
+    cpdef close(self):
+        """
+        Closes the underlying C object of the MR and frees the memory allocated.
+        :return: None
+        """
+        if self.mr != NULL:
+            self.logger.debug('Closing dma-buf MR')
+            rc = v.ibv_dereg_mr(self.mr)
+            if rc != 0:
+                raise PyverbsRDMAError('Failed to dereg dma-buf MR', rc)
+            self.pd = None
+            self.mr = NULL
+            # Set self.mr to NULL before closing dmabuf because this method is
+            # re-entered when close_weakrefs() is called inside dmabuf.close().
+            if self.is_dmabuf_internal:
+                self.dmabuf.close()
+            self.dmabuf = None
+
+    @property
+    def offset(self):
+        return self.offset
+
+    @property
+    def dmabuf(self):
+        return self.dmabuf
+
+    def write(self, data, length, offset=0):
+        """
+        Write user data to the dma-buf backing the MR
+        :param data: User data to write
+        :param length: Length of the data to write
+        :param offset: Writing offset
+        :return: None
+        """
+        if isinstance(data, str):
+            data = data.encode()
+        cdef int off = offset + self.offset
+        cdef void *buf = mmap(NULL, length + off, PROT_READ | PROT_WRITE,
+                              MAP_SHARED, self.dmabuf.drm_fd,
+                              self.dmabuf.map_offset)
+        if buf == MAP_FAILED:
+            raise PyverbsError(f'Failed to map dma-buf of size {length}')
+        memcpy(<char*>(buf + off), <char *>data, length)
+        munmap(buf, length + off)
+
+    cpdef read(self, length, offset):
+        """
+        Reads data from the dma-buf backing the MR
+        :param length: Length of data to read
+        :param offset: Reading offset
+        :return: The data on the buffer in the requested offset
+        """
+        cdef int off = offset + self.offset
+        cdef void *buf = mmap(NULL, length + off, PROT_READ | PROT_WRITE,
+                              MAP_SHARED, self.dmabuf.drm_fd,
+                              self.dmabuf.map_offset)
+        if buf == MAP_FAILED:
+            raise PyverbsError(f'Failed to map dma-buf of size {length}')
+        cdef char *data =<char*>malloc(length)
+        memset(data, 0, length)
+        memcpy(data, <char*>(buf + off), length)
+        munmap(buf, length + off)
+        res = data[:length]
+        free(data)
+        return res
+
 
 def mwtype2str(mw_type):
     mw_types = {1:'IBV_MW_TYPE_1', 2:'IBV_MW_TYPE_2'}