Linaro-mm-sig October 2025

linaro-mm-sig@lists.linaro.org

7 participants
8 discussions

Re: [PATCH v12 2/9] dma-buf: dma-heap: export declared functions

by John Stultz

On Thu, Oct 2, 2025 at 12:47 AM Maxime Ripard <mripard(a)redhat.com> wrote: > On Thu, Sep 11, 2025 at 03:49:43PM +0200, Jens Wiklander wrote: > > Export the dma-buf heap functions to allow them to be used by the OP-TEE > > driver. The OP-TEE driver wants to register and manage specific secure > > DMA heaps with it. > > > > Reviewed-by: Sumit Garg <sumit.garg(a)oss.qualcomm.com> > > Reviewed-by: T.J. Mercier <tjmercier(a)google.com> > > Acked-by: Sumit Semwal <sumit.semwal(a)linaro.org> > > Signed-off-by: Jens Wiklander <jens.wiklander(a)linaro.org> > > --- > > drivers/dma-buf/dma-heap.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c > > index 3cbe87d4a464..8ab49924f8b7 100644 > > --- a/drivers/dma-buf/dma-heap.c > > +++ b/drivers/dma-buf/dma-heap.c > > @@ -11,6 +11,7 @@ > > #include <linux/dma-buf.h> > > #include <linux/dma-heap.h> > > #include <linux/err.h> > > +#include <linux/export.h> > > #include <linux/list.h> > > #include <linux/nospec.h> > > #include <linux/syscalls.h> > > @@ -202,6 +203,7 @@ void *dma_heap_get_drvdata(struct dma_heap *heap) > > { > > return heap->priv; > > } > > +EXPORT_SYMBOL_NS_GPL(dma_heap_get_drvdata, "DMA_BUF_HEAP"); > > > > /** > > * dma_heap_get_name - get heap name > > @@ -214,6 +216,7 @@ const char *dma_heap_get_name(struct dma_heap *heap) > > { > > return heap->name; > > } > > +EXPORT_SYMBOL_NS_GPL(dma_heap_get_name, "DMA_BUF_HEAP"); > > > > /** > > * dma_heap_add - adds a heap to dmabuf heaps > > @@ -303,6 +306,7 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) > > kfree(heap); > > return err_ret; > > } > > +EXPORT_SYMBOL_NS_GPL(dma_heap_add, "DMA_BUF_HEAP"); > > It's not clear to me why we would need to export those symbols. > > As far as I know, heaps cannot be removed, and compiling them as module > means that we would be able to remove them. > > Now, if we don't expect the users to be compiled as modules, then we > don't need to export these symbols at all. > > Am I missing something? For things like distro kernels (or in Android's case, the GKI), there's a benefit for modules that can be loaded permanently (not having a module_exit hook). One doesn't have to bloat the base kernel image/memory usage for everyone, while still not having to necessarily deal with complications from module unloading issues. thanks -john

1 hour, 51 minutes

Re: [PATCH] rust: bindings: add `rust_helper_wait_for_completion` helper function

by Boqun Feng

On Thu, Oct 02, 2025 at 10:06:17AM +0000, Guangbo Cui wrote: > > -extern void wait_for_completion(struct completion *); > > -extern void wait_for_completion_io(struct completion *); > > -extern int wait_for_completion_interruptible(struct completion *x); > > -extern int wait_for_completion_killable(struct completion *x); > > -extern int wait_for_completion_state(struct completion *x, unsigned int state); > > -extern unsigned long wait_for_completion_timeout(struct completion *x, > > +extern void __wait_for_completion(struct completion *); > > +extern void __wait_for_completion_io(struct completion *); > > +extern int __wait_for_completion_interruptible(struct completion *x); > > +extern int __wait_for_completion_killable(struct completion *x); > > +extern int __wait_for_completion_state(struct completion *x, unsigned int state); > > +extern unsigned long __wait_for_completion_timeout(struct completion *x, > > unsigned long timeout); > > -extern unsigned long wait_for_completion_io_timeout(struct completion *x, > > +extern unsigned long __wait_for_completion_io_timeout(struct completion *x, > > unsigned long timeout); > > -extern long wait_for_completion_interruptible_timeout( > > +extern long __wait_for_completion_interruptible_timeout( > > struct completion *x, unsigned long timeout); > > -extern long wait_for_completion_killable_timeout( > > +extern long __wait_for_completion_killable_timeout( > > struct completion *x, unsigned long timeout); > > extern bool try_wait_for_completion(struct completion *x); > > extern bool completion_done(struct completion *x); > > @@ -139,4 +134,79 @@ extern void complete(struct completion *); > > extern void complete_on_current_cpu(struct completion *x); > > extern void complete_all(struct completion *); > > > > +#define wait_for_completion(x) \ > > +({ \ > > + sdt_might_sleep_start_timeout(NULL, -1L); \ > > + __wait_for_completion(x); \ > > + sdt_might_sleep_end(); \ > > +}) > > The DEPT patch series changed `wait_for_completion` into a macro. > Because bindgen cannot handle function-like macros, this caused > Rust build errors. Add a helper function to fix it. > > ``` > error[E0425]: cannot find function `wait_for_completion` in crate `bindings` > --> rust/kernel/sync/completion.rs:110:28 > | > 110 | unsafe { bindings::wait_for_completion(self.as_raw()) }; > | ^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: `__wait_for_completion` > | > ::: /root/linux/rust/bindings/bindings_generated.rs:33440:5 > | > 33440 | pub fn __wait_for_completion(arg1: *mut completion); > | ---------------------------------------------------- similarly named function `__wait_for_completion` defined here > > error: aborting due to 1 previous error > > For more information about this error, try `rustc --explain E0425`. > ``` > I think Danilo already made it clear, please fold this the existing patch. Moreover, since this patchset doesn't adjust init_completion() from the Rust side, the result is Rust code will also use the same dept key for completion, which has to be fixed if dept wants to be in-tree. Regards, Boqun > Signed-off-by: Guangbo Cui <2407018371(a)qq.com> > --- > rust/helpers/completion.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/rust/helpers/completion.c b/rust/helpers/completion.c > index b2443262a2ae..5bae5e749def 100644 > --- a/rust/helpers/completion.c > +++ b/rust/helpers/completion.c > @@ -6,3 +6,8 @@ void rust_helper_init_completion(struct completion *x) > { > init_completion(x); > } > + > +void rust_helper_wait_for_completion(struct completion *x) > +{ > + wait_for_completion(x); > +} > -- > 2.43.0 >

4 hours, 9 minutes

Re: [PATCH v12 3/9] tee: implement protected DMA-heap

by Jens Wiklander

Hi, On Thu, Oct 2, 2025 at 9:54 AM Maxime Ripard <mripard(a)redhat.com> wrote: > > On Thu, Sep 11, 2025 at 03:49:44PM +0200, Jens Wiklander wrote: > > +static const char *heap_id_2_name(enum tee_dma_heap_id id) > > +{ > > + switch (id) { > > + case TEE_DMA_HEAP_SECURE_VIDEO_PLAY: > > + return "protected,secure-video"; > > + case TEE_DMA_HEAP_TRUSTED_UI: > > + return "protected,trusted-ui"; > > + case TEE_DMA_HEAP_SECURE_VIDEO_RECORD: > > + return "protected,secure-video-record"; > > + default: > > + return NULL; > > + } > > +} > > We've recently agreed on a naming guideline (even though it's not merged yet) > > https://lore.kernel.org/r/20250728-dma-buf-heap-names-doc-v4-1-f73f71cf0dfd… I wasn't aware of that (or had forgotten it), but during the revisions of this patch set, we changed to use "protected". > > Secure and trusted should be defined I guess, because secure and > protected at least seem redundant to me. Depending on the use case, the protected buffer is only accessible to a specific set of devices. This is typically configured by the TEE firmware based on which heap we're using. To distinguish between the different heaps, I've simply added the name of the use case after the comma. So the name of the heap for the Trusted-UI use case is "protected,trusted-ui". What would a heap called "protected,ui" represent? Protected buffers for a UI use case? What kind of UI use case? If the name of the heap is too generic, it might cover more than one use case with conflicting requirements for which devices should be able to access the protected memory. Thanks, Jens

8 hours, 40 minutes

Re: [PATCH v12 2/9] dma-buf: dma-heap: export declared functions

by Nicolas Dufresne

Le jeudi 02 octobre 2025 à 09:47 +0200, Maxime Ripard a écrit : > Hi, > > On Thu, Sep 11, 2025 at 03:49:43PM +0200, Jens Wiklander wrote: > > Export the dma-buf heap functions to allow them to be used by the OP-TEE > > driver. The OP-TEE driver wants to register and manage specific secure > > DMA heaps with it. > > > > Reviewed-by: Sumit Garg <sumit.garg(a)oss.qualcomm.com> > > Reviewed-by: T.J. Mercier <tjmercier(a)google.com> > > Acked-by: Sumit Semwal <sumit.semwal(a)linaro.org> > > Signed-off-by: Jens Wiklander <jens.wiklander(a)linaro.org> > > --- > > drivers/dma-buf/dma-heap.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c > > index 3cbe87d4a464..8ab49924f8b7 100644 > > --- a/drivers/dma-buf/dma-heap.c > > +++ b/drivers/dma-buf/dma-heap.c > > @@ -11,6 +11,7 @@ > > #include <linux/dma-buf.h> > > #include <linux/dma-heap.h> > > #include <linux/err.h> > > +#include <linux/export.h> > > #include <linux/list.h> > > #include <linux/nospec.h> > > #include <linux/syscalls.h> > > @@ -202,6 +203,7 @@ void *dma_heap_get_drvdata(struct dma_heap *heap) > > { > > return heap->priv; > > } > > +EXPORT_SYMBOL_NS_GPL(dma_heap_get_drvdata, "DMA_BUF_HEAP"); > > > > /** > > * dma_heap_get_name - get heap name > > @@ -214,6 +216,7 @@ const char *dma_heap_get_name(struct dma_heap *heap) > > { > > return heap->name; > > } > > +EXPORT_SYMBOL_NS_GPL(dma_heap_get_name, "DMA_BUF_HEAP"); > > > > /** > > * dma_heap_add - adds a heap to dmabuf heaps > > @@ -303,6 +306,7 @@ struct dma_heap *dma_heap_add(const struct > > dma_heap_export_info *exp_info) > > kfree(heap); > > return err_ret; > > } > > +EXPORT_SYMBOL_NS_GPL(dma_heap_add, "DMA_BUF_HEAP"); > > It's not clear to me why we would need to export those symbols. > > As far as I know, heaps cannot be removed, and compiling them as module > means that we would be able to remove them. > > Now, if we don't expect the users to be compiled as modules, then we > don't need to export these symbols at all. Maybe I'm getting out of topic, sorry if its the case, but making that a hard rule seems very limiting. Didn't we said that a heap driver could be made to represent memory region on a remote device such as an eGPU ? Nicolas > > Am I missing something? > > Maxime

8 hours, 56 minutes

Re: [PATCH v12 2/9] dma-buf: dma-heap: export declared functions

by Jens Wiklander

Hi, On Thu, Oct 2, 2025 at 9:47 AM Maxime Ripard <mripard(a)redhat.com> wrote: > > Hi, > > On Thu, Sep 11, 2025 at 03:49:43PM +0200, Jens Wiklander wrote: > > Export the dma-buf heap functions to allow them to be used by the OP-TEE > > driver. The OP-TEE driver wants to register and manage specific secure > > DMA heaps with it. > > > > Reviewed-by: Sumit Garg <sumit.garg(a)oss.qualcomm.com> > > Reviewed-by: T.J. Mercier <tjmercier(a)google.com> > > Acked-by: Sumit Semwal <sumit.semwal(a)linaro.org> > > Signed-off-by: Jens Wiklander <jens.wiklander(a)linaro.org> > > --- > > drivers/dma-buf/dma-heap.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c > > index 3cbe87d4a464..8ab49924f8b7 100644 > > --- a/drivers/dma-buf/dma-heap.c > > +++ b/drivers/dma-buf/dma-heap.c > > @@ -11,6 +11,7 @@ > > #include <linux/dma-buf.h> > > #include <linux/dma-heap.h> > > #include <linux/err.h> > > +#include <linux/export.h> > > #include <linux/list.h> > > #include <linux/nospec.h> > > #include <linux/syscalls.h> > > @@ -202,6 +203,7 @@ void *dma_heap_get_drvdata(struct dma_heap *heap) > > { > > return heap->priv; > > } > > +EXPORT_SYMBOL_NS_GPL(dma_heap_get_drvdata, "DMA_BUF_HEAP"); > > > > /** > > * dma_heap_get_name - get heap name > > @@ -214,6 +216,7 @@ const char *dma_heap_get_name(struct dma_heap *heap) > > { > > return heap->name; > > } > > +EXPORT_SYMBOL_NS_GPL(dma_heap_get_name, "DMA_BUF_HEAP"); > > > > /** > > * dma_heap_add - adds a heap to dmabuf heaps > > @@ -303,6 +306,7 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) > > kfree(heap); > > return err_ret; > > } > > +EXPORT_SYMBOL_NS_GPL(dma_heap_add, "DMA_BUF_HEAP"); > > It's not clear to me why we would need to export those symbols. > > As far as I know, heaps cannot be removed, and compiling them as module > means that we would be able to remove them. > > Now, if we don't expect the users to be compiled as modules, then we > don't need to export these symbols at all. > > Am I missing something? In this case, it's the TEE module that _might_ need to instantiate a DMA heap. Whether it will be instantiated depends on the TEE backend driver and the TEE firmware. If a heap is instantiated, then it will not be possible to unload the TEE module. That might not be perfect, but in my opinion, it's better than other options, such as always making the TEE subsystem built-in or disabling DMA-heap support when compiled as a module. Thanks, Jens

9 hours, 20 minutes

Re: [PATCH v17 09/47] arm64, dept: add support CONFIG_ARCH_HAS_DEPT_SUPPORT to arm64

by Mark Brown

On Thu, Oct 02, 2025 at 05:12:09PM +0900, Byungchul Park wrote: > dept needs to notice every entrance from user to kernel mode to treat > every kernel context independently when tracking wait-event dependencies. > Roughly, system call and user oriented fault are the cases. > > Make dept aware of the entrances of arm64 and add support > CONFIG_ARCH_HAS_DEPT_SUPPORT to arm64. The description of what needs to be tracked probably needs some tightening up here, it's not clear to me for example why exceptions for mops or the vector extensions aren't included here, or what the distinction is with error faults like BTI or GCS not being tracked?

9 hours, 58 minutes

Re: [PATCH] rust: bindings: add `rust_helper_wait_for_completion` helper function

by Miguel Ojeda

On Thu, Oct 2, 2025 at 12:12 PM Guangbo Cui <2407018371(a)qq.com> wrote: > > The DEPT patch series changed `wait_for_completion` into a macro. Thanks! In general, it is useful to provide a Link: to Lore to the right patch (i.e. context is good), and please clarify in which tree you found the issue if any -- I don't see it in linux-next, so I imagine it is not applied, but "changed" sounds like it was? If it was actually applied, please also provide a Fixes: tag. Cheers, Miguel

10 hours, 57 minutes

[PATCH v4 00/10] vfio/pci: Allow MMIO regions to be exported through dma-buf

by Leon Romanovsky

Changelog: v4: * Split pcim_p2pdma_provider() to two functions, one that initializes array of providers and another to return right provider pointer. v3: https://lore.kernel.org/all/cover.1758804980.git.leon@kernel.org * Changed pcim_p2pdma_enable() to be pcim_p2pdma_provider(). * Cache provider in vfio_pci_dma_buf struct instead of BAR index. * Removed misleading comment from pcim_p2pdma_provider(). * Moved MMIO check to be in pcim_p2pdma_provider(). v2: https://lore.kernel.org/all/cover.1757589589.git.leon@kernel.org/ * Added extra patch which adds new CONFIG, so next patches can reuse it. * Squashed "PCI/P2PDMA: Remove redundant bus_offset from map state" into the other patch. * Fixed revoke calls to be aligned with true->false semantics. * Extended p2pdma_providers to be per-BAR and not global to whole device. * Fixed possible race between dmabuf states and revoke. * Moved revoke to PCI BAR zap block. v1: https://lore.kernel.org/all/cover.1754311439.git.leon@kernel.org * Changed commit messages. * Reused DMA_ATTR_MMIO attribute. * Returned support for multiple DMA ranges per-dMABUF. v0: https://lore.kernel.org/all/cover.1753274085.git.leonro@nvidia.com --------------------------------------------------------------------------- Based on "[PATCH v6 00/16] dma-mapping: migrate to physical address-based API" https://lore.kernel.org/all/cover.1757423202.git.leonro@nvidia.com/ series. --------------------------------------------------------------------------- This series extends the VFIO PCI subsystem to support exporting MMIO regions from PCI device BARs as dma-buf objects, enabling safe sharing of non-struct page memory with controlled lifetime management. This allows RDMA and other subsystems to import dma-buf FDs and build them into memory regions for PCI P2P operations. The series supports a use case for SPDK where a NVMe device will be owned by SPDK through VFIO but interacting with a RDMA device. The RDMA device may directly access the NVMe CMB or directly manipulate the NVMe device's doorbell using PCI P2P. However, as a general mechanism, it can support many other scenarios with VFIO. This dmabuf approach can be usable by iommufd as well for generic and safe P2P mappings. In addition to the SPDK use-case mentioned above, the capability added in this patch series can also be useful when a buffer (located in device memory such as VRAM) needs to be shared between any two dGPU devices or instances (assuming one of them is bound to VFIO PCI) as long as they are P2P DMA compatible. The implementation provides a revocable attachment mechanism using dma-buf move operations. MMIO regions are normally pinned as BARs don't change physical addresses, but access is revoked when the VFIO device is closed or a PCI reset is issued. This ensures kernel self-defense against potentially hostile userspace. The series includes significant refactoring of the PCI P2PDMA subsystem to separate core P2P functionality from memory allocation features, making it more modular and suitable for VFIO use cases that don't need struct page support. ----------------------------------------------------------------------- The series is based originally on https://lore.kernel.org/all/20250307052248.405803-1-vivek.kasireddy@intel.c… but heavily rewritten to be based on DMA physical API. ----------------------------------------------------------------------- The WIP branch can be found here: https://git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git/log/?h=… Thanks Leon Romanovsky (8): PCI/P2PDMA: Separate the mmap() support from the core logic PCI/P2PDMA: Simplify bus address mapping API PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation PCI/P2PDMA: Export pci_p2pdma_map_type() function types: move phys_vec definition to common header vfio/pci: Add dma-buf export config for MMIO regions vfio/pci: Enable peer-to-peer DMA transactions by default vfio/pci: Add dma-buf export support for MMIO regions Vivek Kasireddy (2): vfio: Export vfio device get and put registration helpers vfio/pci: Share the core device pointer while invoking feature functions block/blk-mq-dma.c | 7 +- drivers/iommu/dma-iommu.c | 4 +- drivers/pci/p2pdma.c | 177 +++++++++---- drivers/vfio/pci/Kconfig | 20 ++ drivers/vfio/pci/Makefile | 2 + drivers/vfio/pci/vfio_pci_config.c | 22 +- drivers/vfio/pci/vfio_pci_core.c | 56 ++-- drivers/vfio/pci/vfio_pci_dmabuf.c | 398 +++++++++++++++++++++++++++++ drivers/vfio/pci/vfio_pci_priv.h | 23 ++ drivers/vfio/vfio_main.c | 2 + include/linux/pci-p2pdma.h | 120 +++++---- include/linux/types.h | 5 + include/linux/vfio.h | 2 + include/linux/vfio_pci_core.h | 3 + include/uapi/linux/vfio.h | 25 ++ kernel/dma/direct.c | 4 +- mm/hmm.c | 2 +- 17 files changed, 750 insertions(+), 122 deletions(-) create mode 100644 drivers/vfio/pci/vfio_pci_dmabuf.c -- 2.51.0

1 day, 9 hours

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