x86/vmx: fix build with clang 3.8.0

The usage of the __transparent__ attribute in 991033fa introduces some issues
when compiled with clang 3.8.0:

xen/include/asm/hvm/vmx/vmx.h:605:15: error: transparent_union attribute can only be
      applied to a union definition; attribute ignored [-Werror,-Wignored-attributes]
typedef union __transparent__ ept_qual {
              ^
xen/include/xen/compiler.h:50:44: note: expanded from macro '__transparent__'

This can be easily fixed by moving the attribute to the end of the definition,
but then the following error triggers:

xen/include/asm/hvm/vmx/vmx.h:607:5: error: size of field '' (16 bits) does not
      match the size of the first field in transparent union; transparent_union attribute ignored
      [-Werror,-Wignored-attributes]
    struct {
    ^
xen/include/asm/hvm/vmx/vmx.h:606:19: note: size of first field is 64 bits
    unsigned long raw;
                  ^

Which can be fixed by introducing a new field in the nested structure that
contains the padding in order to match the size of an unsigned long.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/include/asm-x86/hvm/vmx/vmx.h b/xen/include/asm-x86/hvm/vmx/vmx.h
index 5f7512bd66d867fc5d26a027ba3ea8c1b87a4332..f4183d96150ed8023f4c2496e273755217128144 100644 (file)
--- a/xen/include/asm-x86/hvm/vmx/vmx.h
+++ b/xen/include/asm-x86/hvm/vmx/vmx.h
@@ -602,15 +602,16 @@ void vmx_pi_hooks_assign(struct domain *d);
 void vmx_pi_hooks_deassign(struct domain *d);
 
 /* EPT violation qualifications definitions */
-typedef union __transparent__ ept_qual {
+typedef union ept_qual {
     unsigned long raw;
     struct {
         bool read:1, write:1, fetch:1,
             eff_read:1, eff_write:1, eff_exec:1, /* eff_user_exec */:1,
             gla_valid:1,
             gla_fault:1; /* Valid iff gla_valid. */
+        unsigned long /* pad */:55;
     };
-} ept_qual_t;
+} __transparent__ ept_qual_t;
 
 #define EPT_L4_PAGETABLE_SHIFT      39
 #define EPT_PAGETABLE_ENTRIES       512