I'm puzzled about two inconsistencies with other alternative_vcall<N>() here: There's a check missing that the supplied function pointer is actually pointing to a function taking no args. And there's a pointless pair of parentheses. Correct both.
Fixes: 67d01cdb5518 ("x86: infrastructure to allow converting certain indirect calls to direct ones") Signed-off-by: Jan Beulich <jbeul...@suse.com> --- a/xen/include/asm-x86/alternative.h +++ b/xen/include/asm-x86/alternative.h @@ -218,7 +218,8 @@ extern void alternative_branches(void); #define alternative_vcall0(func) ({ \ ALT_CALL_NO_ARG1; \ - ((void)alternative_callN(0, int, func)); \ + (void)sizeof(func()); \ + (void)alternative_callN(0, int, func); \ }) #define alternative_call0(func) ({ \