Crucible + recent Mesa seems to sometimes hit:
GEM_BUG_ON(num_ccs_blks > NUM_CCS_BLKS_PER_XFER)
And it looks like we can also trigger this with gem_lmem_swapping, if we
modify the test to use slightly larger object sizes.
Looking closer it looks like we have the following issues in
migrate_copy():
- We are using plain integer in various places, which we can easily overflow
with a large object.
- We pass the entire object size (when the src is lmem) into
emit_pte() and then try to copy it, which doesn't work, since we
only have a few fixed sized windows in which to map the pages and
perform the copy. With an object > 8M we therefore aren't properly
copying the pages. And then with an object > 64M we trigger the
GEM_BUG_ON(num_ccs_blks > NUM_CCS_BLKS_PER_XFER).
So it looks like our copy handling for any object > 8M (which is our
CHUNK_SZ) is currently broken on DG2.
Fixes: da0595ae91da ("drm/i915/migrate: Evict and restore the flatccs capable lmem obj")
Testcase: igt@gem_lmem_swapping@basic-big
Testcase: igt@gem_lmem_swapping@verify-ccs-big
Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Cc: Ramalingam C <ramalingam.c@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_migrate.c | 44 ++++++++++++-------------
1 file changed, 21 insertions(+), 23 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c b/drivers/gpu/drm/i915/gt/intel_migrate.c
index 1bbed7aa436a..aaaf1906026c 100644
--- a/drivers/gpu/drm/i915/gt/intel_migrate.c
+++ b/drivers/gpu/drm/i915/gt/intel_migrate.c
@@ -609,9 +609,9 @@ static int emit_copy(struct i915_request *rq,
return 0;
}
-static int scatter_list_length(struct scatterlist *sg)
+static u64 scatter_list_length(struct scatterlist *sg)
{
- int len = 0;
+ u64 len = 0;
while (sg && sg_dma_len(sg)) {
len += sg_dma_len(sg);
@@ -621,28 +621,26 @@ static int scatter_list_length(struct scatterlist *sg)
return len;
}
-static void
+static int
calculate_chunk_sz(struct drm_i915_private *i915, bool src_is_lmem,
- int *src_sz, u32 bytes_to_cpy, u32 ccs_bytes_to_cpy)
+ u64 bytes_to_cpy, u64 ccs_bytes_to_cpy)
{
- if (ccs_bytes_to_cpy) {
- if (!src_is_lmem)
- /*
- * When CHUNK_SZ is passed all the pages upto CHUNK_SZ
- * will be taken for the blt. in Flat-ccs supported
- * platform Smem obj will have more pages than required
- * for main meory hence limit it to the required size
- * for main memory
- */
- *src_sz = min_t(int, bytes_to_cpy, CHUNK_SZ);
- } else { /* ccs handling is not required */
- *src_sz = CHUNK_SZ;
- }
+ if (ccs_bytes_to_cpy && !src_is_lmem)
+ /*
+ * When CHUNK_SZ is passed all the pages upto CHUNK_SZ
+ * will be taken for the blt. in Flat-ccs supported
+ * platform Smem obj will have more pages than required
+ * for main meory hence limit it to the required size
+ * for main memory
+ */
+ return min_t(u64, bytes_to_cpy, CHUNK_SZ);
+ else
+ return CHUNK_SZ;
}
-static void get_ccs_sg_sgt(struct sgt_dma *it, u32 bytes_to_cpy)
+static void get_ccs_sg_sgt(struct sgt_dma *it, u64 bytes_to_cpy)
{
- u32 len;
+ u64 len;
do {
GEM_BUG_ON(!it->sg || !sg_dma_len(it->sg));
@@ -673,12 +671,12 @@ intel_context_migrate_copy(struct intel_context *ce,
{
struct sgt_dma it_src = sg_sgt(src), it_dst = sg_sgt(dst), it_ccs;
struct drm_i915_private *i915 = ce->engine->i915;
- u32 ccs_bytes_to_cpy = 0, bytes_to_cpy;
+ u64 ccs_bytes_to_cpy = 0, bytes_to_cpy;
enum i915_cache_level ccs_cache_level;
u32 src_offset, dst_offset;
u8 src_access, dst_access;
struct i915_request *rq;
- int src_sz, dst_sz;
+ u64 src_sz, dst_sz;
bool ccs_is_src, overwrite_ccs;
int err;
@@ -761,8 +759,8 @@ intel_context_migrate_copy(struct intel_context *ce,
if (err)
goto out_rq;
- calculate_chunk_sz(i915, src_is_lmem, &src_sz,
- bytes_to_cpy, ccs_bytes_to_cpy);
+ src_sz = calculate_chunk_sz(i915, src_is_lmem,
+ bytes_to_cpy, ccs_bytes_to_cpy);
len = emit_pte(rq, &it_src, src_cache_level, src_is_lmem,
src_offset, src_sz);
--
2.37.1
