diff options
Diffstat (limited to 'include/hw')
| -rw-r--r-- | include/hw/xen/interface/io/ring.h | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/include/hw/xen/interface/io/ring.h b/include/hw/xen/interface/io/ring.h index 1adacf09f9..5d048b335c 100644 --- a/include/hw/xen/interface/io/ring.h +++ b/include/hw/xen/interface/io/ring.h @@ -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. */ |