While locating the start of ccs scatterlist in smem scatterlist, that has
to be the size of lmem obj size + corresponding ccs data size, report bug
if scatterlist terminate before that length.
v2:
s/GEM_BUG_ON/BUG_ON with more commenting [Matt]
v3:
Converted GEM_BUG_ON into BUG_ON with more documentation [Matt]
Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx>
Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx> (v1)
---
drivers/gpu/drm/i915/gt/intel_migrate.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c b/drivers/gpu/drm/i915/gt/intel_migrate.c
index 9d552f30b627..168d17b6f48a 100644
--- a/drivers/gpu/drm/i915/gt/intel_migrate.c
+++ b/drivers/gpu/drm/i915/gt/intel_migrate.c
@@ -687,6 +687,16 @@ static void get_ccs_sg_sgt(struct sgt_dma *it, u32 bytes_to_cpy)
bytes_to_cpy -= len;
it->sg = __sg_next(it->sg);
+
+ /*
+ * On Flat-CCS capable platform when we back the lmem pages with
+ * smem pages we add extra pages at the end of the smem
+ * scatterlist, to store the ccs data corresponding to the lmem
+ * pages. get_ccs_sg_sgt() is called to get the pointer for the
+ * start of the extra pages added at the end of smem scatterlist.
+ * So scatterlist can't end at or before bytes_to_cpy.
+ */
+ BUG_ON(!it->sg);
it->dma = sg_dma_address(it->sg);
it->max = it->dma + sg_dma_len(it->sg);
} while (bytes_to_cpy);
@@ -748,8 +758,10 @@ intel_context_migrate_copy(struct intel_context *ce,
* Need to fix it.
*/
ccs_bytes_to_cpy = src_sz != dst_sz ? GET_CCS_BYTES(i915, bytes_to_cpy) : 0;
- if (ccs_bytes_to_cpy)
+ if (ccs_bytes_to_cpy) {
+ WARN_ON(abs(src_sz - dst_sz) < ccs_bytes_to_cpy);
get_ccs_sg_sgt(&it_ccs, bytes_to_cpy);
+ }
}
src_offset = 0;
--
2.20.1
