On Tue, 2024-12-10 at 17:15 +0100, Nirmoy Das wrote:
Fix a potential GPU page fault during tt -> system moves by waiting for migration jobs to complete before unmapping SG. This ensures that IOMMU mappings are not prematurely torn down while a migration job is still in progress.
v2: Use intr=false(Matt A) v3: Update commit message(Matt A)
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/3466 Fixes: 75521e8b56e8 ("drm/xe: Perform dma_map when moving system buffer objects to TT") Cc: Thomas Hellström thomas.hellstrom@linux.intel.com Cc: Matthew Brost matthew.brost@intel.com Cc: Lucas De Marchi lucas.demarchi@intel.com Cc: stable@vger.kernel.org # v6.11+ Cc: Matthew Auld matthew.auld@intel.com Signed-off-by: Nirmoy Das nirmoy.das@intel.com Reviewed-by: Matthew Auld matthew.auld@intel.com
drivers/gpu/drm/xe/xe_bo.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c index 06931df876ab..0a41b6c0583a 100644 --- a/drivers/gpu/drm/xe/xe_bo.c +++ b/drivers/gpu/drm/xe/xe_bo.c @@ -857,8 +857,16 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, out: if ((!ttm_bo->resource || ttm_bo->resource->mem_type == XE_PL_SYSTEM) &&
- ttm_bo->ttm)
- ttm_bo->ttm) {
long timeout = dma_resv_wait_timeout(ttm_bo-base.resv,
DMA_RESV_USAGE_BOOKKEEP,
false,MAX_SCHEDULE_TIMEOUT);
if (timeout < 0)ret = timeout;xe_tt_unmap_sg(ttm_bo->ttm);
- }
return ret; }
I assume here we're waiting for the move fence, right? However if @evict is true, we should hit the ttm_bo_wait_free_node() path. In what cases do we hit this without evict being true?
Also, shouldn't it be sufficient to wait for DMA_RESV_USAGE_KERNEL here?
Thanks, Thomas