[DNM][Do Not Review][WiP][PoC] userspace LL scheduling: LLEXT & multicore - #10945
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lyakh wants to merge 16 commits into
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[DNM][Do Not Review][WiP][PoC] userspace LL scheduling: LLEXT & multicore#10945lyakh wants to merge 16 commits into
lyakh wants to merge 16 commits into
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This was referenced Jul 14, 2026
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After multiple PRs got merged we're down from 108 commits to 32 |
This was referenced Aug 20, 2026
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let me mark it "ready" to have some on-device testing |
lyakh
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Pull request overview
This PR is a WiP/PoC that extends the SOF Zephyr userspace low-latency (LL) work to support LLEXT and multi-core operation, including new syscalls and userspace IPC/LL thread infrastructure per core.
Changes:
- Adds a userspace-accessible vregion syscall interface and vregion-to-mem-domain mapping support.
- Introduces per-core userspace IPC threads and secondary-core initialization plumbing for userspace LL.
- Refactors DP/LL scheduler interactions for multicore and userspace execution contexts, plus library manager changes to support userspace/module-loading flow.
Reviewed changes
Copilot reviewed 29 out of 29 changed files in this pull request and generated 7 comments.
Show a summary per file
| File | Description |
|---|---|
| zephyr/syscall/vregion.c | Adds Zephyr syscall verifiers/marshalling for vregion operations. |
| zephyr/lib/vregion.c | Implements z_impl_* syscall backends, vregion mapping into a mem domain, and userspace verification. |
| zephyr/lib/userspace_helper.c | Adjusts mailbox partition mapping logic for IPC4 userspace access. |
| zephyr/Kconfig | Adds/selects userspace vregion interface Kconfig option. |
| zephyr/CMakeLists.txt | Registers new syscall headers/sources for vregion and other headers needed by syscalls. |
| uuid-registry.txt | Adds UUID entry used for secondary-core init task. |
| src/schedule/zephyr_ll.c | Updates LL tick path and scheduler data source for userspace LL. |
| src/schedule/zephyr_dp_schedule.h | Removes internal prototypes no longer intended for this header. |
| src/schedule/zephyr_dp_schedule.c | Converts scheduler_dp_ll_tick to a syscall-capable z_impl/z_vrfy API; uses userspace scheduler data. |
| src/schedule/zephyr_dp_schedule_application.c | Updates DP IPC paths and adds syscall verifier for DP internal free. |
| src/schedule/zephyr_domain.c | Adds helper to retrieve the LL domain thread for current core. |
| src/library_manager/llext_manager.c | Changes userspace LL domain add/remove behavior for LLEXT mappings. |
| src/library_manager/lib_manager.c | Refactors module creation to a reusable helper and adds syscall for module free; adjusts userspace/module interactions. |
| src/ipc/ipc4/helper.c | Adds helper to pre-load modules in kernel context for userspace LL flows. |
| src/ipc/ipc4/handler-user.c | Routes more IPC4 messages to per-core userspace handling and adjusts init path for LL vs DP. |
| src/ipc/ipc-common.c | Implements per-core userspace IPC threads, per-core stacks/events/threads, and secondary-core userspace init. |
| src/init/init.c | Hooks secondary-core init to start userspace IPC/LL infrastructure when enabled. |
| src/include/sof/schedule/schedule.h | Adds scheduler_list_get_data() and scheduler_get_user_data() helper for userspace schedulers. |
| src/include/sof/schedule/ll_schedule_domain.h | Exposes zephyr_ll_domain_thread(). |
| src/include/sof/schedule/dp_schedule.h | Exposes scheduler_dp_ll_tick and scheduler_dp_internal_free as syscalls for Zephyr full-app builds. |
| src/include/sof/lib/vregion.h | Exposes vregion syscalls (create_map/get/put/alloc/free/set_interim) and verification helper. |
| src/include/sof/lib_manager.h | Exposes lib_manager_mod_create_priv() and lib_manager_free_module syscall/z_impl mapping. |
| src/include/sof/ipc/common.h | Extends ipc_user struct for per-core threads/events/audio threads; updates ipc_user_forward_cmd signature; declares secondary init helpers. |
| src/include/ipc4/handler.h | Declares ipc4_user_module_load(). |
| src/audio/pipeline/pipeline-graph.c | Adds LL domain include needed by userspace LL changes. |
| src/audio/mux/mux_ipc4.c | Tightens IPC4 mux blob size validation. |
| src/audio/module_adapter/module_adapter.c | Switches DP module heap to vregion_create_map() under userspace constraints. |
| src/audio/buffers/comp_buffer.c | Fixes alloc context free path when vregion-backed allocations are used. |
| app/overlays/ptl/ll_userspace_overlay.conf | Updates overlay config for the evolving userspace LL setup. |
Suppressed comments (2)
zephyr/lib/vregion.c:279
- vregion_unmap(vr) runs after vpage_free(vr->base). This leaves a window where userspace can still access the partition while the backing memory is already freed/reusable, and unmapping may also rely on the region still being valid. Unmap partitions before freeing the backing pages.
LOG_DBG(" lifetime used %zu free count %d", vr->lifetime.used, vr->lifetime.free_count);
vpage_free(vr->base);
vregion_unmap(vr);
rfree(vr);
src/ipc/ipc-common.c:342
- ipc_user_forward_cmd() uses 'core' to index init_needed[] and event[] with no bounds checking. core ultimately comes from IPC fields and can be out of range, leading to out-of-bounds access and memory corruption.
int ipc_user_forward_cmd(uint32_t primary, uint32_t extension, unsigned int core)
{
struct ipc *ipc = ipc_get();
struct ipc_user *pdata = ipc->ipc_user_pdata;
k_spinlock_key_t key;
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| struct k_mem_domain *domain = zephyr_ll_mem_domain(); | ||
| struct k_mem_partition part = { | ||
| .start = *vreg_start, | ||
| .size = *vreg_size, | ||
| .attr = K_MEM_PARTITION_P_RW_U_RW | XTENSA_MMU_CACHED_WB, | ||
| }; | ||
| int ret = k_mem_domain_add_partition(domain, &part); | ||
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| if (ret < 0) { | ||
| vregion_put(vr); | ||
| return NULL; | ||
| } | ||
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| part.start = (uintptr_t)sys_cache_uncached_ptr_get((void *)part.start); | ||
| part.attr = K_MEM_PARTITION_P_RW_U_RW; | ||
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| ret = k_mem_domain_add_partition(domain, &part); | ||
| if (ret < 0) { | ||
| vregion_put(vr); | ||
| return NULL; | ||
| } | ||
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| vr->domain = domain; |
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| size_t vr_size = 0; | ||
| uintptr_t vr_start; | ||
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| vregion_mem_info(vr, &vr_size, &vr_start); |
Comment on lines
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| struct vregion *z_vrfy_vregion_create_map(uintptr_t *vreg_start, size_t *vreg_size) | ||
| { | ||
| K_OOPS(K_SYSCALL_MEMORY_WRITE(vreg_start, sizeof(*vreg_start))); | ||
| K_OOPS(K_SYSCALL_MEMORY_WRITE(vreg_size, sizeof(*vreg_size))); | ||
| return z_impl_vregion_create_map(vreg_start, vreg_size); | ||
| } |
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| void z_vrfy_scheduler_dp_ll_tick(unsigned int core) | ||
| { | ||
| z_impl_scheduler_dp_ll_tick(core); | ||
| } |
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| case MOD_TYPE_IADK: | ||
| agent = &system_agent_start; | ||
| ops = &processing_module_adapter_interface; | ||
| agent_iface = (const void **)&adapter_priv; | ||
| *ops = &processing_module_adapter_interface; | ||
| agent_iface = (const void **)adapter_priv; | ||
| break; |
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| struct userspace_context *userspace = NULL; | ||
| const struct module_interface *ops = NULL; | ||
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| return lib_manager_mod_create_priv(drv, &ipc_config, &spec, NULL, &userspace, &ops); | ||
| } |
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| assert_can_be_cold(); | ||
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.cold and .coldrodata partitions can be empty, avoid a failure in such cases. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Extract a privileged LLEXT-related part from lib_manager_module_create() into a separate function to be called from kernel context. At the same time lib_manager_mod_free_priv() already executes privileged operations; to make it callable in userspace, convert lib_manager_free_module() to a system call. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
ipc4_init_module_instance() should be called when CONFIG_SOF_USERSPACE_LL isn't selected but also when initializing a DP module. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
If LL runs in userspace, it needs access to loaded LLEXT modules, running in DP more too. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
The DP scheduler runs tasks in userspace mode, it's registered with the user scheduler list, therefore it should use scheduler_get_user_data(), not scheduler_get_data(). Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
scheduler_dp_ll_tick(() has to recalculate DP deadlines and reschedule DP threads. Make it a syscall to be able to call it from the userspace LL scheduler. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Make scheduler_dp_internal_free() a syscall in the "application" DP implementation. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Make scheduling LL thread and synchronisation objects per-core and forward IPCs and scheduling events accordingly. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
In case of userspace LL scheduling the (also userspace) IPC thread needs access rights to DP assets like the thread itself and its stack and synchronisation primitives. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
The LL userspace thread has to interact with the DP one. Grant required rights. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Switching to the userspace mode in DP and LL cases differs. Add a comment to explain that. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Extract common initialisation code from comp_new_ipc4_user() and comp_new_ipc4() into a new function. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
When running in syscall context on behalf of a userspace thread dynamically mapped memory doesn't automatically become accessible. To make it accessible it has to be added to the thread memory domain. This is a problem for loadable modules with executable cold sections. To be able to execute them they have to be mapped to threads with the executable bit set. While for linking that memory has to be mapped writable. To solve the problem we perform linking from the kernel IPC context before forwarding to the userspace IPC thread. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
LLEXT is now working with userspace LL and can be enabled. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
CONFIG_COLD_STORE_EXECUTE_DRAM can now be re-enabled for userspace LL. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
The DP scheduler can now be user with userspace LL. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
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This includes #10558 and my patches on top to enable LLEXT and multicore. Current status: passes simple tests with nocodec with both core 0 and core 1 streaming. 2 streams simultaneously run into a problem when the first of them terminates. WiP.