illumos gate

Depending on whether 32 or 64-bit illumos Xen PV kernel is being built, cpp conditionals in usr/src/uts/common/xen/public/arch-x86/xen.h select the right xen-x86_XXX.h file to include (32 or 64-bit one) as can be seen here.

The first check is to see if __i386__ macro has been defined. If it is - 32-bit file is used. SmartOS and OmniOS both use open source cpp in /usr/lib. Its source can be found here. 64-bit header file is never used on the systems above as __i386__ is one of /usr/lib/cpp built-ins and is defined by default.

I propose making the change below to make 64-bit PV kernels usable when compiled with open source cpp in /usr/lib:

diff --git a/usr/src/uts/common/xen/public/arch-x86/xen.h b/usr/src/uts/common/xen/public/arch-x86/xen.h
index d416387..a7ffd4f 100644
--- a/usr/src/uts/common/xen/public/arch-x86/xen.h
+++ b/usr/src/uts/common/xen/public/arch-x86/xen.h
@@ -49,7 +49,7 @@
 #define get_xen_guest_handle(val, hnd)  do { val = (hnd).p; } while (0)
 #endif

-#if defined(__i386__)
+#if defined(__i386)
 #include "xen-x86_32.h" 
 #elif defined(__x86_64__)
 #include "xen-x86_64.h" 

__i386 is undefined for 64-bit C compiler and assembler wrapper invocations and can be used instead of __i386__ to select the right include file.