diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/fb/ramgf100.c b/drivers/gpu/drm/nouveau/nvkm/subdev/fb/ramgf100.c
index 53c32fc694e949b1e1d3bb461704f2beb3366827..c63975907c907da7afc433398d49c99137fca04d 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/fb/ramgf100.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/fb/ramgf100.c
@@ -589,7 +589,7 @@ gf100_ram_ctor(const struct nvkm_ram_func *func, struct nvkm_fb *fb,
 			nvkm_debug(subdev, "FBP %d: %4d MiB, %d LTC(s)\n",
 				   fbp, size, ltcs);
 			lcomm  = min(lcomm, (u64)(size / ltcs) << 20);
-			total += size << 20;
+			total += (u64) size << 20;
 			ltcn  += ltcs;
 		} else {
 			nvkm_debug(subdev, "FBP %d: disabled\n", fbp);