v3d: Add V3D_TFU_READAHEAD padding for allocated resources
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36159>
diff --git a/src/gallium/drivers/v3d/v3d_resource.c b/src/gallium/drivers/v3d/v3d_resource.c
index 0ac9256..eecca1f 100644
--- a/src/gallium/drivers/v3d/v3d_resource.c
+++ b/src/gallium/drivers/v3d/v3d_resource.c
@@ -102,17 +102,18 @@
struct pipe_screen *pscreen = prsc->screen;
struct v3d_bo *bo;
- /* Buffers may be read using ldunifa, which prefetches the next
- * 4 bytes after a read. If the buffer's size is exactly a multiple
- * of a page size and the shader reads the last 4 bytes with ldunifa
- * the prefetching would read out of bounds and cause an MMU error,
- * so we allocate extra space to avoid kernel error spamming.
+ /* Buffers may be read using ldunifa, which prefetches the next 4
+ * bytes after a read. If the buffer's size is exactly a multiple of a
+ * page size and the shader reads the last 4 bytes with ldunifa the
+ * prefetching would read out of bounds and cause an MMU error, so we
+ * allocate extra space to avoid kernel error spamming. We also need
+ * to add a V3D_TFU_READAHEAD padding to avoid invalid reads done by
+ * the TFU unit after the end of the last page allocated.
*/
- uint32_t size = rsc->size;
- if (rsc->base.target == PIPE_BUFFER && (size % 4096 == 0))
- size += 4;
-
- bo = v3d_bo_alloc(v3d_screen(pscreen), size, "resource");
+ uint32_t padding =
+ rsc->base.target == PIPE_BUFFER ? 4 : V3D_TFU_READAHEAD_SIZE;
+ bo = v3d_bo_alloc(v3d_screen(pscreen), rsc->size + padding,
+ "resource");
if (bo) {
v3d_bo_unreference(&rsc->bo);
rsc->bo = bo;
