diff options
| author | Adrián Larumbe <adrian.larumbe@collabora.com> | 2026-04-08 22:12:23 +0300 |
|---|---|---|
| committer | Adrián Larumbe <adrian.larumbe@collabora.com> | 2026-04-13 18:16:07 +0300 |
| commit | 8867262d993d249309a8d3ec28ce095378cf1720 (patch) | |
| tree | da8a5ad3dc2d2d8e325edd83d9b39dfffca8cc69 | |
| parent | 2d76319c4cbb19eccfca71fa05d40a6b4ce7fc3d (diff) | |
| download | linux-8867262d993d249309a8d3ec28ce095378cf1720.tar.xz | |
drm/panthor: Extend VM locked region for remap case to be a superset
In the event of an sm_step_remap() that leads to a partial unmap of a
transparent huge page, the new locked region required by an extended unmap
might not be a superset of the original one. Then, if it leaves a portion
of the initially requested one out, the ensuing map will trigger a warning.
Fixes: 8e7460eac786 ("drm/panthor: Support partial unmaps of huge pages")
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patch.msgid.link/20260408191228.537625-1-adrian.larumbe@collabora.com
Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
| -rw-r--r-- | drivers/gpu/drm/panthor/panthor_mmu.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c index 41604a7aaf85..888fafc938a7 100644 --- a/drivers/gpu/drm/panthor/panthor_mmu.c +++ b/drivers/gpu/drm/panthor/panthor_mmu.c @@ -1638,6 +1638,25 @@ static int panthor_vm_lock_region(struct panthor_vm *vm, u64 start, u64 size) start + size <= vm->locked_region.start + vm->locked_region.size) return 0; + /* sm_step_remap() may need a locked region that isn't a strict superset + * of the original one because of having to extend unmap boundaries beyond + * it to deal with partial unmaps of transparent huge pages. What we want + * in those cases is to lock the union of both regions. The new region must + * always overlap with the original one, because the upper and lower unmap + * boundaries in a remap operation can only shift up or down respectively, + * but never otherwise. + */ + if (vm->locked_region.size) { + u64 end = max(vm->locked_region.start + vm->locked_region.size, + start + size); + + drm_WARN_ON_ONCE(&vm->ptdev->base, (start + size <= vm->locked_region.start) || + (start >= vm->locked_region.start + vm->locked_region.size)); + + start = min(start, vm->locked_region.start); + size = end - start; + } + mutex_lock(&ptdev->mmu->as.slots_lock); if (vm->as.id >= 0 && size) { /* Lock the region that needs to be updated */ |