On Thu, 2024-12-05 at 12:40 +0000, Matthew Auld wrote:
On 05/12/2024 12:02, Nirmoy Das wrote:
There could be still migration job going on while doing xe_tt_unmap_sg() which could trigger GPU page faults. Fix this by waiting for the migration job to finish.
v2: Use intr=false(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
Ok, so this is something like ttm_bo_move_to_ghost() doing a pipeline move for tt -> system, but we then do xe_tt_unmap_sg() too early which tears down the IOMMU (if enabled) mappings whilst the job is in progress?
Maybe add some more info to the commit message? I think this for sure fixes it. Just wondering if it's somehow possible to keep the mapping until the job is done, since all tt -> sys moves are now synced here?
Unless Thomas has a better idea here,
Not at the moment. Ideally we should somehow attach the dma-map to the ghost object. Perhaps moving forward we could look at attaching it to the XE_PL_TT resource. Then I believe it will get freed with the ghost object.
/Thomas
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 b2aa368a23f8..c906a5529db0 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; }