@@ -33,6 +33,13 @@
* - standard integers types (uint8_t, uint16_t, etc)
* They are provided by stdint.h of the standard headers.
*
+ * Before using the different macros, you need to provide the following
+ * macros:
+ * - xen_mb() a memory barrier
+ * - xen_rmb() a read memory barrier
+ * - xen_wmb() a write memory barrier
+ * Example of those can be found in xenctrl.h.
+ *
* In addition, if you intend to use the FLEX macros, you also need to
* provide the following, before invoking the FLEX macros:
* - size_t
@@ -42,12 +49,6 @@
* and grant_table.h from the Xen public headers.
*/
-#if __XEN_INTERFACE_VERSION__ < 0x00030208
-#define xen_mb() mb()
-#define xen_rmb() rmb()
-#define xen_wmb() wmb()
-#endif
-
typedef unsigned int RING_IDX;
/* Round a 32-bit unsigned constant down to the nearest power of two. */
The xen_[rw]?mb() macros defined in ring.h can't be used and the fact that there are gated behind __XEN_INTERFACE_VERSION__ means that it needs to be defined somewhere. QEMU doesn't implement interfaces with the Xen hypervisor so defining __XEN_INTERFACE_VERSION__ is pointless. This leads to: include/hw/xen/io/ring.h:47:5: error: "__XEN_INTERFACE_VERSION__" is not defined, evaluates to 0 [-Werror=undef] Cleanup ring.h. The xen_*mb() macros are already defined in xenctrl.h which is included in xen_common.h. Reported-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190704153605.4140-1-anthony.perard@citrix.com> [aperard: Adding the comment proposed upstream] Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> --- include/hw/xen/interface/io/ring.h | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)