[PATCH] drm/virtio: fix undefined behavior in capset shift calculation

[Alexey Simakov <bigalex934@gmail.com>]

According to MAX_CAPSET_ID, possible values of vgdev->capsets[i].id
range from 0 to 63. Since the intermediate calculation uses type int,
shifting by values larger than the bit width of int is undefined
behavior as per the C language standard.

Explicitly cast the left-shift operand to ULL to prevent undefined
behavior during the calculation.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Fixes: 1925d6a7e0f4 ("drm/virtio: implement context init: track valid capabilities in a mask")
Signed-off-by: Alexey Simakov <bigalex934@gmail.com>
---
 drivers/gpu/drm/virtio/virtgpu_kms.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 1c15cbf326b7..2e0ec7590ac2 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -104,7 +104,7 @@ static void virtio_gpu_get_capsets(struct virtio_gpu_device *vgdev,
 			return;
 		}
 
-		vgdev->capset_id_mask |= 1 << vgdev->capsets[i].id;
+		vgdev->capset_id_mask |= 1ULL << vgdev->capsets[i].id;
 		DRM_INFO("cap set %d: id %d, max-version %d, max-size %d\n",
 			 i, vgdev->capsets[i].id,
 			 vgdev->capsets[i].max_version,
-- 
2.34.1