On Fri, Jul 22, 2022 at 5:01 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
>
> On Fri, Jul 22, 2022, David Matlack wrote:
> > Change KVM_EXCEPTION_MAGIC to use the all-caps "ULL", rather than lower
> > case. This fixes a build failure with Clang:
> >
> > In file included from x86_64/hyperv_features.c:13:
> > include/x86_64/processor.h:825:9: error: unexpected token in argument list
> > return kvm_asm_safe("wrmsr", "a"(val & -1u), "d"(val >> 32), "c"(msr));
> > ^
> > include/x86_64/processor.h:802:15: note: expanded from macro 'kvm_asm_safe'
> > asm volatile(KVM_ASM_SAFE(insn) \
> > ^
> > include/x86_64/processor.h:785:2: note: expanded from macro 'KVM_ASM_SAFE'
> > "mov $" __stringify(KVM_EXCEPTION_MAGIC) ", %%r9\n\t" \
> > ^
> > <inline asm>:1:18: note: instantiated into assembly here
> > mov $0xabacadabaull, %r9
> > ^
> >
> > Fixes: 3b23054cd3f5 ("KVM: selftests: Add x86-64 support for exception fixup")
> > Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
> > ---
>
> Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
>
> > tools/testing/selftests/kvm/include/x86_64/processor.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
> > index 45edf45821d0..51c6661aca77 100644
> > --- a/tools/testing/selftests/kvm/include/x86_64/processor.h
> > +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
> > @@ -754,7 +754,7 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
> > void (*handler)(struct ex_regs *));
> >
> > /* If a toddler were to say "abracadabra". */
> > -#define KVM_EXCEPTION_MAGIC 0xabacadabaull
> > +#define KVM_EXCEPTION_MAGIC 0xabacadabaULL
>
> Really?!?!?! That's what makes clang happy?!?!?
Heh, yup. I was surprised when it worked.
Hopefully some of the Clang folks CC'd can shed some light on why.
