Hello,
Let me introduce the new ioctls, which are intended to allow gntdev to
map scatter-gather table on top of the existing dmabuf, referenced by
file descriptor.
When using dma-buf exporter to create dma-buf with backing storage and
map it to the grant refs, provided from the domain, we've met a problem,
that several HW (i.MX8 gpu in our case) do not support external buffer
and requires backing storage to be created using it's native tools.
That's why new ioctls were added to be able to pass existing dma-buffer
fd as input parameter and use it as backing storage to export to refs.
Following calls were added:
IOCTL_GNTDEV_DMABUF_MAP_REFS_TO_BUF - map existing buffer as the backing
storage and export it to the provided grant refs;
IOCTL_GNTDEV_DMABUF_MAP_RELEASE - detach buffer from the grant table and
set notification to unmap grant refs before releasing the external
buffer. After this call the external buffer should be detroyed.
IOCTL_GNTDEV_DMABUF_MAP_WAIT_RELEASED - wait for timeout until buffer is
completely destroyed and gnt refs unmapped so domain could free grant
pages. Should be called after buffer was destoyed.
Our setup is based on IMX8QM board. We're trying to implement zero-copy
support for DomU graphics using Wayland zwp_linux_dmabuf_v1_interface
implementation.
For dma-buf exporter we used i.MX8 gpu native tools to create backing
storage grant-refs, received from DomU. Buffer for the backing storage was
allocated using gbm_bo_create call because gpu do not support external
buffer and requires backing storage to be created using it's native tools
(eglCreateImageKHR returns EGL_NO_IMAGE_KHR for buffers, which were not
created using gbm_bo_create).
This behaviour was also tested on Qemu setup using
DRM_IOCTL_MODE_CREATE_DUMB call to create backing storage buffer.
---
Oleksii Moisieiev (3):
xen/grant-table: save page_count on map and use if during async
unmapping
dma-buf: add dma buffer release notifier callback
xen/grant-table: add new ioctls to map dmabuf to existing fd
drivers/dma-buf/dma-buf.c | 44 ++++
drivers/xen/gntdev-common.h | 8 +-
drivers/xen/gntdev-dmabuf.c | 416 +++++++++++++++++++++++++++++++++++-
drivers/xen/gntdev-dmabuf.h | 7 +
drivers/xen/gntdev.c | 101 ++++++++-
drivers/xen/grant-table.c | 73 +++++--
include/linux/dma-buf.h | 15 ++
include/uapi/xen/gntdev.h | 62 ++++++
include/xen/grant_table.h | 8 +
9 files changed, 703 insertions(+), 31 deletions(-)
--
2.25.1
Add a new ioctl called TEE_IOC_SHM_REGISTER_FD to register a
shared memory from a dmabuf file descriptor.
This new ioctl will allow the Linux Kernel to register a buffer
to be used by the Secure Data Path OPTEE OS feature.
Please find more information here:
https://static.linaro.org/connect/san19/presentations/san19-107.pdf
Patch tested on Hikey 6220.
Etienne Carriere (1):
tee: new ioctl to a register tee_shm from a dmabuf file descriptor
drivers/tee/tee_core.c | 38 +++++++++++++++
drivers/tee/tee_shm.c | 99 +++++++++++++++++++++++++++++++++++++++-
include/linux/tee_drv.h | 11 +++++
include/uapi/linux/tee.h | 29 ++++++++++++
4 files changed, 175 insertions(+), 2 deletions(-)
--
2.25.0
Based on discussions at LPC, this series adds a memory.stat counter for
exported dmabufs. This counter allows us to continue tracking
system-wide total exported buffer sizes which there is no longer any
way to get without DMABUF_SYSFS_STATS, and adds a new capability to
track per-cgroup exported buffer sizes. The total (root counter) is
helpful for accounting in-kernel dmabuf use (by comparing with the sum
of child nodes or with the sum of sizes of mapped buffers or FD
references in procfs) in addition to helping identify driver memory
leaks when in-kernel use continually increases over time. With
per-application cgroups, the per-cgroup counter allows us to quickly
see how much dma-buf memory an application has caused to be allocated.
This avoids the need to read through all of procfs which can be a
lengthy process, and causes the charge to "stick" to the allocating
process/cgroup as long as the buffer is alive, regardless of how the
buffer is shared (unless the charge is transferred).
The first patch adds the counter to memcg. The next two patches allow
the charge for a buffer to be transferred across cgroups which is
necessary because of the way most dmabufs are allocated from a central
process on Android. The fourth patch adds the binder object flags to
the existing selinux_binder_transfer_file LSM hook and a SELinux
permission for charge transfers.
[1] https://lore.kernel.org/all/20220617085702.4298-1-christian.koenig@amd.com/
v2:
Actually charge memcg vs just mutate the stat counter per Shakeel Butt
and Michal Hocko. Shakeel pointed me at the skmem functions which
turned out to be very similar to how I was thinking the dmabuf tracking
should work. So I've added a pair of dmabuf functions that do
essentially the same thing, except conditionally implemented behind
CONFIG_MEMCG alongside the other charge/uncharge functions.
Drop security_binder_transfer_charge per Casey Schaufler and Paul Moore
Drop BINDER_FDA_FLAG_XFER_CHARGE (and fix commit message) per Carlos
Llamas
Don't expose is_dma_buf_file for use by binder per Hillf Danton
Call dma_buf_stats_teardown in dma_buf_export error handling
Rebase onto v6.2-rc5
Hridya Valsaraju (1):
binder: Add flags to relinquish ownership of fds
T.J. Mercier (3):
memcg: Track exported dma-buffers
dmabuf: Add cgroup charge transfer function
security: binder: Add binder object flags to
selinux_binder_transfer_file
Documentation/admin-guide/cgroup-v2.rst | 5 ++
drivers/android/binder.c | 27 ++++++++--
drivers/dma-buf/dma-buf.c | 69 +++++++++++++++++++++++++
include/linux/dma-buf.h | 4 ++
include/linux/lsm_hook_defs.h | 2 +-
include/linux/lsm_hooks.h | 5 +-
include/linux/memcontrol.h | 43 +++++++++++++++
include/linux/security.h | 6 ++-
include/uapi/linux/android/binder.h | 19 +++++--
mm/memcontrol.c | 19 +++++++
security/security.c | 4 +-
security/selinux/hooks.c | 13 ++++-
security/selinux/include/classmap.h | 2 +-
13 files changed, 201 insertions(+), 17 deletions(-)
base-commit: 2241ab53cbb5cdb08a6b2d4688feb13971058f65
--
2.39.0.246.g2a6d74b583-goog
To make it easier to find the dma-buf documentation when looking through
tables-of-contents etc., put the name "dma-buf" in the title.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer(a)gmx.net>
---
Documentation/driver-api/dma-buf.rst | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst
index 622b8156d2127..61b6f42ed0f18 100644
--- a/Documentation/driver-api/dma-buf.rst
+++ b/Documentation/driver-api/dma-buf.rst
@@ -1,5 +1,5 @@
-Buffer Sharing and Synchronization
-==================================
+Buffer Sharing and Synchronization (dma-buf)
+============================================
The dma-buf subsystem provides the framework for sharing buffers for
hardware (DMA) access across multiple device drivers and subsystems, and
--
2.39.0
Hi guys,
this is just an RFC! The last time we discussed the DMA-buf coherency
problem [1] we concluded that DMA-heap first needs a better way to
communicate to userspace which heap to use for a certain device.
As far as I know userspace currently just hard codes that information
which is certainly not desirable considering that we should have this
inside the kernel as well.
So what those two patches here do is to first add some
dma_heap_create_device_link() and dma_heap_remove_device_link()
function and then demonstrating the functionality with uvcvideo
driver.
The preferred DMA-heap is represented with a symlink in sysfs between
the device and the virtual DMA-heap device node.
What's still missing is certainly matching userspace for this since I
wanted to discuss the initial kernel approach first.
Please take a look and comment.
Thanks,
Christian.
[1] https://lore.kernel.org/all/11a6f97c-e45f-f24b-8a73-48d5a388a2cc@gmail.com/…
Based on discussions at LPC, this series adds a memory.stat counter for
exported dmabufs. This counter allows us to continue tracking
system-wide total exported buffer sizes which there is no longer any
way to get without DMABUF_SYSFS_STATS, and adds a new capability to
track per-cgroup exported buffer sizes. The total (root counter) is
helpful for accounting in-kernel dmabuf use (by comparing with the sum
of child nodes or with the sum of sizes of mapped buffers or FD
references in procfs) in addition to helping identify driver memory
leaks when in-kernel use continually increases over time. With
per-application cgroups, the per-cgroup counter allows us to quickly
see how much dma-buf memory an application has caused to be allocated.
This avoids the need to read through all of procfs which can be a
lengthy process, and causes the charge to "stick" to the allocating
process/cgroup as long as the buffer is alive, regardless of how the
buffer is shared (unless the charge is transferred).
The first patch adds the counter to memcg. The next two patches allow
the charge for a buffer to be transferred across cgroups which is
necessary because of the way most dmabufs are allocated from a central
process on Android. The fourth patch adds a SELinux hook to binder in
order to control who is allowed to transfer buffer charges.
[1] https://lore.kernel.org/all/20220617085702.4298-1-christian.koenig@amd.com/
Hridya Valsaraju (1):
binder: Add flags to relinquish ownership of fds
T.J. Mercier (3):
memcg: Track exported dma-buffers
dmabuf: Add cgroup charge transfer function
security: binder: Add transfer_charge SElinux hook
Documentation/admin-guide/cgroup-v2.rst | 5 +++
drivers/android/binder.c | 36 +++++++++++++++--
drivers/dma-buf/dma-buf.c | 54 +++++++++++++++++++++++--
include/linux/dma-buf.h | 5 +++
include/linux/lsm_hook_defs.h | 2 +
include/linux/lsm_hooks.h | 6 +++
include/linux/memcontrol.h | 7 ++++
include/linux/security.h | 2 +
include/uapi/linux/android/binder.h | 23 +++++++++--
mm/memcontrol.c | 4 ++
security/security.c | 6 +++
security/selinux/hooks.c | 9 +++++
security/selinux/include/classmap.h | 2 +-
13 files changed, 149 insertions(+), 12 deletions(-)
base-commit: b7bfaa761d760e72a969d116517eaa12e404c262
--
2.39.0.314.g84b9a713c41-goog