x86, xen: short-circuit tests for dom0

When testing for a dom0/initial/privileged domain, make sure the
predicate evaluates to a compile-time 0 if CONFIG_XEN_DOM0 isn't
enabled.  This will make most of the dom0 code evaporate without
much more effort.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 18 insertions, 10 deletions

diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h
index 81fbd735aec4..d5b7e90c0edf 100644
--- a/arch/x86/include/asm/xen/hypervisor.h
+++ b/arch/x86/include/asm/xen/hypervisor.h
@@ -38,22 +38,30 @@ extern struct shared_info *HYPERVISOR_shared_info;
 extern struct start_info *xen_start_info;
 
 enum xen_domain_type {
-        XEN_NATIVE,
-        XEN_PV_DOMAIN,
-        XEN_HVM_DOMAIN,
+        XEN_NATIVE,             /* running on bare hardware    */
+        XEN_PV_DOMAIN,          /* running in a PV domain      */
+        XEN_HVM_DOMAIN,         /* running in a Xen hvm domain */
 };
 
-extern enum xen_domain_type xen_domain_type;
-
 #ifdef CONFIG_XEN
-#define xen_domain()            (xen_domain_type != XEN_NATIVE)
+extern enum xen_domain_type xen_domain_type;
 #else
-#define xen_domain()            (0)
+#define xen_domain_type         XEN_NATIVE
 #endif
 
-#define xen_pv_domain()         (xen_domain() && xen_domain_type == XEN_PV_DOMAIN)
-#define xen_hvm_domain()        (xen_domain() && xen_domain_type == XEN_HVM_DOMAIN)
+#define xen_domain()            (xen_domain_type != XEN_NATIVE)
+#define xen_pv_domain()         (xen_domain() &&                        \
+                                 xen_domain_type == XEN_PV_DOMAIN)
+#define xen_hvm_domain()        (xen_domain() &&                        \
+                                 xen_domain_type == XEN_HVM_DOMAIN)
+
+#ifdef CONFIG_XEN_DOM0
+#include <xen/interface/xen.h>
 
-#define xen_initial_domain()    (xen_pv_domain() && xen_start_info->flags & SIF_INITDOMAIN)
+#define xen_initial_domain()    (xen_pv_domain() && \
+                                 xen_start_info->flags & SIF_INITDOMAIN)
+#else  /* !CONFIG_XEN_DOM0 */
+#define xen_initial_domain()    (0)
+#endif  /* CONFIG_XEN_DOM0 */
 
 #endif /* _ASM_X86_XEN_HYPERVISOR_H */