Commit d297e533 authored Jul 04, 2019 by Anthony PERARD

xen: Fix ring.h header



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>

parent dac03af5

include/hw/xen/interface/io/ring.h

+7 −6

Original line number	Diff line number	Diff line
		@@ -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. */