mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-07-22 03:27:30 -04:00
Code Issues Packages Projects Releases Wiki Activity

drm/xe: Wait on external BO kernel fences in exec IOCTL

Browse Source 
Before arming a user job, xe_exec_ioctl() only added the VM's
dma-resv KERNEL slot as a dependency. That slot covers rebinds and
the kernel operations of the VM's private BOs, but not external BOs
(bo->vm == NULL), which carry their kernel operations (evictions,
moves, ...) in their own dma-resv KERNEL slot.

The DMA_RESV_USAGE_KERNEL slot is the cross-driver contract for
memory management operations that must complete before the BO or its
backing store may be used: any accessor is required to wait on the
KERNEL fences before touching the resv. By skipping the external BOs'
KERNEL slots, the exec path violated that contract and could schedule
a user job while a kernel operation on an external BO mapped by the VM
was still in flight, racing against it and potentially reading or
writing memory that was being moved.

Replace the VM-only dependency with an iteration over every object
locked by the exec, adding each object's KERNEL slot as a job
dependency. This covers the VM resv (rebinds and private BOs) as well
as every external BO, mirroring the drm_gpuvm_resv_add_fence() call
that later publishes the job fence to the same set of objects.
Long-running mode continues to skip this, as before.

Fixes: dd08ebf6c3 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: stable@vger.kernel.org
Assisted-by: GitHub_Copilot:claude-opus-4.8
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patch.msgid.link/20260702215805.4011228-1-matthew.brost@intel.com
(cherry picked from commit a6b842acf3ddd1efc53a56de9260cfa718fb35e7)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
This commit is contained in:
Matthew Brost
2026-07-02 14:58:05 -07:00
committed by Thomas Hellström
parent 34a4dd45cf
commit af80e2bfde
1 changed files with 16 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/gpu/drm/xe/xe_exec.c
View File

@@ -292,13 +292,23 @@ int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
goto err_exec;
}
/* Wait behind rebinds */
/*
* Wait behind rebinds and any kernel operations (evictions, defrag
* moves, ...) on the VM and all external BOs. The VM's private BOs
* carry their kernel ops in the VM dma-resv KERNEL slot, while each
* external BO carries them in its own dma-resv KERNEL slot; both are
* covered by iterating every object locked by the exec, mirroring the
* drm_gpuvm_resv_add_fence() below.
*/
if (!xe_vm_in_lr_mode(vm)) {
err = xe_sched_job_add_deps(job,
xe_vm_resv(vm),
DMA_RESV_USAGE_KERNEL);
if (err)
goto err_put_job;
struct drm_gem_object *obj;
drm_exec_for_each_locked_object(exec, obj) {
err = xe_sched_job_add_deps(job, obj->resv,
DMA_RESV_USAGE_KERNEL);
if (err)
goto err_put_job;
}
}
for (i = 0; i < num_syncs && !err; i++)