[PATCH] xen: update PV-device interface headers

[Juergen Gross]

Update the Xen PV-device interface headers in order to avoid undefined
behavior with flexible arrays being defined with one array element.

Reported-by: Pry Mar <pryorm09@xxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 include/xen/interface/io/displif.h | 2 +-
 include/xen/interface/io/ring.h    | 2 +-
 include/xen/interface/io/sndif.h   | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/xen/interface/io/displif.h b/include/xen/interface/io/displif.h
index 18417b017869..60e42d3b760e 100644
--- a/include/xen/interface/io/displif.h
+++ b/include/xen/interface/io/displif.h
@@ -537,7 +537,7 @@ struct xendispl_dbuf_create_req {
 
 struct xendispl_page_directory {
 	grant_ref_t gref_dir_next_page;
-	grant_ref_t gref[1]; /* Variable length */
+	grant_ref_t gref[];
 };
 
 /*
diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h
index ba4c4274b714..4fef1efcdcab 100644
--- a/include/xen/interface/io/ring.h
+++ b/include/xen/interface/io/ring.h
@@ -95,7 +95,7 @@ struct __name##_sring {                                                 \
     RING_IDX req_prod, req_event;                                       \
     RING_IDX rsp_prod, rsp_event;                                       \
     uint8_t __pad[48];                                                  \
-    union __name##_sring_entry ring[1]; /* variable-length */           \
+    union __name##_sring_entry ring[];                                  \
 };                                                                      \
                                                                         \
 /* "Front" end's private variables */                                   \
diff --git a/include/xen/interface/io/sndif.h b/include/xen/interface/io/sndif.h
index 445657cdb1de..b818517588b5 100644
--- a/include/xen/interface/io/sndif.h
+++ b/include/xen/interface/io/sndif.h
@@ -659,7 +659,7 @@ struct xensnd_open_req {
 
 struct xensnd_page_directory {
 	grant_ref_t gref_dir_next_page;
-	grant_ref_t gref[1]; /* Variable length */
+	grant_ref_t gref[];
 };
 
 /*
-- 
2.35.3