Re: [XEN PATCH 03/10] x86: address some violations of MISRA C Rule 20.7

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

On 2024-02-29 17:37, Jan Beulich wrote:
> On 29.02.2024 16:27, Nicola Vetrini wrote:
> > --- a/xen/arch/x86/include/asm/irq.h
> > +++ b/xen/arch/x86/include/asm/irq.h
> > @@ -179,9 +179,9 @@ void cleanup_domain_irq_mapping(struct domain *d);
> >      void *__ret = radix_tree_lookup(&(d)->arch.hvm.emuirq_pirq, 
> > emuirq);\
> >      __ret ? radix_tree_ptr_to_int(__ret) : IRQ_UNBOUND;               
> >   \
> >  })
> > -#define IRQ_UNBOUND -1
> > -#define IRQ_PT -2
> > -#define IRQ_MSI_EMU -3
> > +#define IRQ_UNBOUND (-1)
> > +#define IRQ_PT      (-2)
> > +#define IRQ_MSI_EMU (-3)
> >
> >  bool cpu_has_pending_apic_eoi(void);
> I'd be happy to ack this change right away.
>
> > --- a/xen/arch/x86/usercopy.c
> > +++ b/xen/arch/x86/usercopy.c
> > @@ -106,7 +106,7 @@ unsigned int copy_from_guest_ll(void *to, const 
> > void __user *from, unsigned int
> >      return n;
> >  }
> >
> > -#if GUARD(1) + 0
> > +#if GUARD((1)) + 0
> I don't even understand the need for this one, and nothing is said in
> the description in that regard. Generally I'm afraid I'm averse to
> such (seemingly) redundant parentheses in macro invocations.
It's because
#define UA_KEEP(args...) args
#define GUARD UA_KEEP

which would expand to #if 1 + 0, while the rule demands #if (1) + 0
I did note in the message after --- that I didn't wanna touch UA_KEEP so 
I did this instead, which I'm not particularly happy about either. I can 
remove this and deviate, there is no other issue with GUARD.
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)