We've discussed a number of times of how some heap names are bad, but
not really what makes a good heap name.
Let's document what we expect the heap names to look like.
Signed-off-by: Maxime Ripard <mripard(a)kernel.org>
---
Documentation/userspace-api/dma-buf-heaps.rst | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/Documentation/userspace-api/dma-buf-heaps.rst b/Documentation/userspace-api/dma-buf-heaps.rst
index 535f49047ce6450796bf4380c989e109355efc05..b24618e360a9a9ba0bd85135d8c1760776f1a37f 100644
--- a/Documentation/userspace-api/dma-buf-heaps.rst
+++ b/Documentation/userspace-api/dma-buf-heaps.rst
@@ -21,5 +21,24 @@ following heaps:
usually created either through the kernel commandline through the
`cma` parameter, a memory region Device-Tree node with the
`linux,cma-default` property set, or through the `CMA_SIZE_MBYTES` or
`CMA_SIZE_PERCENTAGE` Kconfig options. Depending on the platform, it
might be called ``reserved``, ``linux,cma``, or ``default-pool``.
+
+Naming Convention
+=================
+
+A good heap name is a name that:
+
+- Is stable, and won't change from one version to the other;
+
+- Describes the memory region the heap will allocate from, and will
+ uniquely identify it in a given platform;
+
+- Doesn't use implementation details, such as the allocator;
+
+- Can describe intended usage.
+
+For example, assuming a platform with a reserved memory region located
+at the RAM address 0x42000000, intended to allocate video framebuffers,
+and backed by the CMA kernel allocator. Good names would be
+`memory@42000000` or `video@42000000`, but `cma-video` wouldn't.
---
base-commit: 92a09c47464d040866cf2b4cd052bc60555185fb
change-id: 20250520-dma-buf-heap-names-doc-31261aa0cfe6
Best regards,
--
Maxime Ripard <mripard(a)kernel.org>
Dear All,
This patchset fixes the incorrect use of dma_sync_sg_*() calls in
media and related drivers. They are replaced with much safer
dma_sync_sgtable_*() variants, which take care of passing the proper
number of elements for the sync operation.
Best regards
Marek Szyprowski, PhD
Samsung R&D Institute Poland
Change log:
v3: added cc: stable to tags
v2: fixes typos and added cc: stable
Patch summary:
Marek Szyprowski (3):
media: videobuf2: use sgtable-based scatterlist wrappers
udmabuf: use sgtable-based scatterlist wrappers
media: omap3isp: use sgtable-based scatterlist wrappers
drivers/dma-buf/udmabuf.c | 5 ++---
drivers/media/common/videobuf2/videobuf2-dma-sg.c | 4 ++--
drivers/media/platform/ti/omap3isp/ispccdc.c | 8 ++++----
drivers/media/platform/ti/omap3isp/ispstat.c | 6 ++----
4 files changed, 10 insertions(+), 13 deletions(-)
--
2.34.1
On Thu, May 29, 2025 at 10:41:15PM +0800, Xu Yilun wrote:
> > On AMD, the host can "revoke" at any time, at worst it'll see RMP
> > events from IOMMU. Thanks,
>
> Is the RMP event firstly detected by host or guest? If by host,
> host could fool guest by just suppress the event. Guest thought the
> DMA writting is successful but it is not and may cause security issue.
Is that in scope of the threat model though? Host must not be able to
change DMAs or target them to different memory, but the host can stop
DMA and loose it, surely?
Host controls the PCI memory enable bit, doesn't it?
Jason
On Tue, May 20, 2025 at 5:27 AM Tomeu Vizoso <tomeu(a)tomeuvizoso.net> wrote:
>
> Add the bindings for the Neural Processing Unit IP from Rockchip.
>
> v2:
> - Adapt to new node structure (one node per core, each with its own
> IOMMU)
> - Several misc. fixes from Sebastian Reichel
>
> v3:
> - Split register block in its constituent subblocks, and only require
> the ones that the kernel would ever use (Nicolas Frattaroli)
> - Group supplies (Rob Herring)
> - Explain the way in which the top core is special (Rob Herring)
>
> v4:
> - Change required node name to npu@ (Rob Herring and Krzysztof Kozlowski)
> - Remove unneeded items: (Krzysztof Kozlowski)
> - Fix use of minItems/maxItems (Krzysztof Kozlowski)
> - Add reg-names to list of required properties (Krzysztof Kozlowski)
> - Fix example (Krzysztof Kozlowski)
>
> v5:
> - Rename file to rockchip,rk3588-rknn-core.yaml (Krzysztof Kozlowski)
> - Streamline compatible property (Krzysztof Kozlowski)
>
> Signed-off-by: Sebastian Reichel <sebastian.reichel(a)collabora.com>
> Signed-off-by: Tomeu Vizoso <tomeu(a)tomeuvizoso.net>
> ---
> .../bindings/npu/rockchip,rk3588-rknn-core.yaml | 147 +++++++++++++++++++++
> 1 file changed, 147 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/npu/rockchip,rk3588-rknn-core.yaml b/Documentation/devicetree/bindings/npu/rockchip,rk3588-rknn-core.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..9eb426367afcbc03c387d43c4b8250cdd1b9ee86
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/npu/rockchip,rk3588-rknn-core.yaml
> @@ -0,0 +1,147 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/npu/rockchip,rk3588-rknn-core.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Neural Processing Unit IP from Rockchip
> +
> +maintainers:
> + - Tomeu Vizoso <tomeu(a)tomeuvizoso.net>
> +
> +description:
> + Rockchip IP for accelerating inference of neural networks, based on NVIDIA's
> + open source NVDLA IP.
> +
> + There is to be a node per each core in the NPU. In Rockchip's design there
> + will be one core that is special and needs to be powered on before any of the
> + other cores can be used. This special core is called the top core and should
> + have the compatible string that corresponds to top cores.
Is this really a distinction in the h/w? If you change which core is
the top one in the DT, does it still work?
> +
> +properties:
> + $nodename:
> + pattern: '^npu@[a-f0-9]+$'
> +
> + compatible:
> + enum:
> + - rockchip,rk3588-rknn-core-top
> + - rockchip,rk3588-rknn-core
> +
> + reg:
> + maxItems: 3
> +
> + reg-names:
> + items:
> + - const: pc
> + - const: cna
> + - const: core
> +
> + clocks:
> + minItems: 2
> + maxItems: 4
> +
> + clock-names:
> + items:
> + - const: aclk
> + - const: hclk
> + - const: npu
> + - const: pclk
> + minItems: 2
It is odd that the non-top cores only have bus clocks and no module
clock. But based on the clock names, I'm guessing the aclk/hclk are
not shared, but the npu and pclk are shared. Since you make the top
core probe first, then it will enable the shared clocks and the
non-top cores don't have to worry about them. If so, that is wrong as
it is letting the software design define the bindings.
Rob
Until CONFIG_DMABUF_SYSFS_STATS was added [1] it was only possible to
perform per-buffer accounting with debugfs which is not suitable for
production environments. Eventually we discovered the overhead with
per-buffer sysfs file creation/removal was significantly impacting
allocation and free times, and exacerbated kernfs lock contention. [2]
dma_buf_stats_setup() is responsible for 39% of single-page buffer
creation duration, or 74% of single-page dma_buf_export() duration when
stressing dmabuf allocations and frees.
I prototyped a change from per-buffer to per-exporter statistics with a
RCU protected list of exporter allocations that accommodates most (but
not all) of our use-cases and avoids almost all of the sysfs overhead.
While that adds less overhead than per-buffer sysfs, and less even than
the maintenance of the dmabuf debugfs_list, it's still *additional*
overhead on top of the debugfs_list and doesn't give us per-buffer info.
This series uses the existing dmabuf debugfs_list to implement a BPF
dmabuf iterator, which adds no overhead to buffer allocation/free and
provides per-buffer info. The list has been moved outside of
CONFIG_DEBUG_FS scope so that it is always populated. The BPF program
loaded by userspace that extracts per-buffer information gets to define
its own interface which avoids the lack of ABI stability with debugfs.
This will allow us to replace our use of CONFIG_DMABUF_SYSFS_STATS, and
the plan is to remove it from the kernel after the next longterm stable
release.
[1] https://lore.kernel.org/linux-media/20201210044400.1080308-1-hridya@google.…
[2] https://lore.kernel.org/all/20220516171315.2400578-1-tjmercier@google.com
v1: https://lore.kernel.org/all/20250414225227.3642618-1-tjmercier@google.com
v1 -> v2:
Make the DMA buffer list independent of CONFIG_DEBUG_FS per Christian
König
Add CONFIG_DMA_SHARED_BUFFER check to kernel/bpf/Makefile per kernel
test robot
Use BTF_ID_LIST_SINGLE instead of BTF_ID_LIST_GLOBAL_SINGLE per Song Liu
Fixup comment style, mixing code/declarations, and use ASSERT_OK_FD in
selftest per Song Liu
Add BPF_ITER_RESCHED feature to bpf_dmabuf_reg_info per Alexei
Starovoitov
Add open-coded iterator and selftest per Alexei Starovoitov
Add a second test buffer from the system dmabuf heap to selftests
Use the BPF program we'll use in production for selftest per Alexei
Starovoitov
https://r.android.com/c/platform/system/bpfprogs/+/3616123/2/dmabufIter.chttps://r.android.com/c/platform/system/memory/libmeminfo/+/3614259/1/libdm…
v2: https://lore.kernel.org/all/20250504224149.1033867-1-tjmercier@google.com
v2 -> v3:
Rebase onto bpf-next/master
Move get_next_dmabuf() into drivers/dma-buf/dma-buf.c, along with the
new get_first_dmabuf(). This avoids having to expose the dmabuf list
and mutex to the rest of the kernel, and keeps the dmabuf mutex
operations near each other in the same file. (Christian König)
Add Christian's RB to dma-buf: Rename debugfs symbols
Drop RFC: dma-buf: Remove DMA-BUF statistics
v3: https://lore.kernel.org/all/20250507001036.2278781-1-tjmercier@google.com
v3 -> v4:
Fix selftest BPF program comment style (not kdoc) per Alexei Starovoitov
Fix dma-buf.c kdoc comment style per Alexei Starovoitov
Rename get_first_dmabuf / get_next_dmabuf to dma_buf_iter_begin /
dma_buf_iter_next per Christian König
Add Christian's RB to bpf: Add dmabuf iterator
v4: https://lore.kernel.org/all/20250508182025.2961555-1-tjmercier@google.com
v4 -> v5:
Add Christian's Acks to all patches
Add Song Liu's Acks
Move BTF_ID_LIST_SINGLE and DEFINE_BPF_ITER_FUNC closer to usage per
Song Liu
Fix open-coded iterator comment style per Song Liu
Move iterator termination check to its own subtest per Song Liu
Rework selftest buffer creation per Song Liu
Fix spacing in sanitize_string per BPF CI
v5: https://lore.kernel.org/all/20250512174036.266796-1-tjmercier@google.com
v5 -> v6:
Song Liu:
Init test buffer FDs to -1
Zero-init udmabuf_create for future proofing
Bail early for iterator fd/FILE creation failure
Dereference char ptr to check for NUL in sanitize_string()
Move map insertion from create_test_buffers() to test_dmabuf_iter()
Add ACK to selftests/bpf: Add test for open coded dmabuf_iter
v6: https://lore.kernel.org/all/20250513163601.812317-1-tjmercier@google.com
v6 -> v7:
Zero uninitialized name bytes following the end of name strings per
s390x BPF CI
Reorder sanitize_string bounds checks per Song Liu
Add Song's Ack to: selftests/bpf: Add test for dmabuf_iter
Rebase onto bpf-next/master per BPF CI
T.J. Mercier (5):
dma-buf: Rename debugfs symbols
bpf: Add dmabuf iterator
bpf: Add open coded dmabuf iterator
selftests/bpf: Add test for dmabuf_iter
selftests/bpf: Add test for open coded dmabuf_iter
drivers/dma-buf/dma-buf.c | 98 ++++--
include/linux/dma-buf.h | 4 +-
kernel/bpf/Makefile | 3 +
kernel/bpf/dmabuf_iter.c | 150 +++++++++
kernel/bpf/helpers.c | 5 +
.../testing/selftests/bpf/bpf_experimental.h | 5 +
tools/testing/selftests/bpf/config | 3 +
.../selftests/bpf/prog_tests/dmabuf_iter.c | 285 ++++++++++++++++++
.../testing/selftests/bpf/progs/dmabuf_iter.c | 101 +++++++
9 files changed, 632 insertions(+), 22 deletions(-)
create mode 100644 kernel/bpf/dmabuf_iter.c
create mode 100644 tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c
create mode 100644 tools/testing/selftests/bpf/progs/dmabuf_iter.c
base-commit: 6888a036cfc3d617d0843ecc9bd8504e91fb9de6
--
2.49.0.1151.ga128411c76-goog
6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Zimmermann <tzimmermann(a)suse.de>
commit 8260731ccad0451207b45844bb66eb161a209218 upstream.
Test struct drm_gem_object.import_attach to detect imported objects.
During object clenanup, the dma_buf field might be NULL. Testing it in
an object's free callback then incorrectly does a cleanup as for native
objects. Happens for calls to drm_mode_destroy_dumb_ioctl() that
clears the dma_buf field in drm_gem_object_exported_dma_buf_free().
v3:
- only test for import_attach (Boris)
v2:
- use import_attach.dmabuf instead of dma_buf (Christian)
Signed-off-by: Thomas Zimmermann <tzimmermann(a)suse.de>
Fixes: b57aa47d39e9 ("drm/gem: Test for imported GEM buffers with helper")
Reported-by: Andy Yan <andyshrk(a)163.com>
Closes: https://lore.kernel.org/dri-devel/38d09d34.4354.196379aa560.Coremail.andysh…
Tested-by: Andy Yan <andyshrk(a)163.com>
Cc: Thomas Zimmermann <tzimmermann(a)suse.de>
Cc: Anusha Srivatsa <asrivats(a)redhat.com>
Cc: Christian König <christian.koenig(a)amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst(a)linux.intel.com>
Cc: Maxime Ripard <mripard(a)kernel.org>
Cc: David Airlie <airlied(a)gmail.com>
Cc: Simona Vetter <simona(a)ffwll.ch>
Cc: Sumit Semwal <sumit.semwal(a)linaro.org>
Cc: "Christian König" <christian.koenig(a)amd.com>
Cc: dri-devel(a)lists.freedesktop.org
Cc: linux-media(a)vger.kernel.org
Cc: linaro-mm-sig(a)lists.linaro.org
Reviewed-by: Boris Brezillon <boris.brezillon(a)collabora.com>
Reviewed-by: Simona Vetter <simona.vetter(a)ffwll.ch>
Link: https://lore.kernel.org/r/20250416065820.26076-1-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
include/drm/drm_gem.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -580,8 +580,7 @@ static inline bool drm_gem_object_is_sha
*/
static inline bool drm_gem_is_imported(const struct drm_gem_object *obj)
{
- /* The dma-buf's priv field points to the original GEM object. */
- return obj->dma_buf && (obj->dma_buf->priv != obj);
+ return !!obj->import_attach;
}
#ifdef CONFIG_LOCKDEP