[PATCH] x86/emul: Work around MISRA R13.2 complaint

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Rule 13.2 states: "The value of an expression and its persistent side effects
shall be the same under all permitted evaluation orders".

Eclair complains about a Rule 13.2 violations because validate_far_branch()
assigns to rc, and the entirety of commit_far_branch() is also assigned to rc.

I'm unsure that the complaint is accurate, but rewriting commit_far_branch()
to use the comma operator seems to make Eclair happy.

Reported-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
---
 xen/arch/x86/x86_emulate/x86_emulate.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index 8e14ebb35b0e..6ee64cb85987 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -333,12 +333,14 @@ do {                                                      
              \
                               : (ip) > (cs)->limit, X86_EXC_GP, 0);     \
 })
 
-#define commit_far_branch(cs, newip) ({                                 \
-    validate_far_branch(cs, newip);                                     \
-    _regs.r(ip) = (newip);                                              \
-    singlestep = _regs.eflags & X86_EFLAGS_TF;                          \
-    ops->write_segment(x86_seg_cs, cs, ctxt);                           \
-})
+#define commit_far_branch(cs, newip) (                                  \
+        ({                                                              \
+            validate_far_branch(cs, newip);                             \
+            _regs.r(ip) = (newip);                                      \
+            singlestep = _regs.eflags & X86_EFLAGS_TF;                  \
+        }),                                                             \
+        ops->write_segment(x86_seg_cs, cs, ctxt)                        \
+    )
 
 int x86emul_get_fpu(
     enum x86_emulate_fpu_type type,

base-commit: 9b3a02e66f058ebd77db6628e3144352857bdf2b
-- 
2.39.5