On 12/5/2024 1:40 PM, 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@xxxxxxxxxxxxxxx> >> Cc: Matthew Brost <matthew.brost@xxxxxxxxx> >> Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx> >> Cc: <stable@xxxxxxxxxxxxxxx> # v6.11+ >> Cc: Matthew Auld <matthew.auld@xxxxxxxxx> >> Signed-off-by: Nirmoy Das <nirmoy.das@xxxxxxxxx> > > 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? Yes, this exactly what is happening for this issue. > > Maybe add some more info to the commit message? I will add more details. > 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, > Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx> Thanks, Nirmoy > >> --- >> 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; >> } >
