Re: [PATCH] x86/jailhouse: fix building without X86_X2APIC

[Dou Liyang]

Hi Arnd,

[...]
> > The reason I don't want to expose the x2apic_mode and x2apic_phys is
> > that they may be misused in X2APIC=n case. So I create an interface to
> > wrap it. do you think so? ;-)
>
> I'm not sure I follow what the intention of that is. If you want to hide

My purpose of that is hiding the variables in X2APIC=n case.

> those two variables, maybe make them 'static' and remove the extern
> declarations?

Yes, that's what I really want, But due to the simple "x2apic_phys= 1"
operation, doing that may be too fat, I guess.

> > diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
> > index 98722773391d..ac25ac2e49af 100644
> > --- a/arch/x86/include/asm/apic.h
> > +++ b/arch/x86/include/asm/apic.h
> > @@ -251,6 +251,11 @@ static inline u64 native_x2apic_icr_read(void)
> >
> >   extern int x2apic_mode;
> >   extern int x2apic_phys;
> > +static inline void apic_set_x2apic_phys(void)
> > +{
> > +       x2apic_phys = 1;
> > +}
> > +
> >   extern void __init check_x2apic(void);
> >   extern void x2apic_setup(void);
> >   static inline int x2apic_enabled(void)
> > @@ -265,7 +270,10 @@ static inline void x2apic_setup(void) { }
> >   static inline int x2apic_enabled(void) { return 0; }
> >
> >   #define x2apic_mode            (0)
> > -#define        x2apic_supported()      (0)
> > +#define x2apic_phys            (0)
> > +#define x2apic_supported()     (0)
> > +
> > +static inline void apic_set_x2apic_phys(void){}
> >   #endif /* !CONFIG_X86_X2APIC */
> >
> >   struct irq_data;
>
> I see nothing wrong it with this, but also don't see anything it does
> that improves the interface.

Another way we can choice is wrap the code with "CONFIG_X86_X2APIC".

Thanks,
	dou
--------------------------------8<------------------------------------
diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c
index d6d5976a9b51..d4aee43c8912 100644
--- a/arch/x86/kernel/jailhouse.c
+++ b/arch/x86/kernel/jailhouse.c
@@ -65,6 +65,7 @@ static void __init jailhouse_get_smp_config(unsigned 
int early)
        };
        unsigned int cpu;

+#ifdef CONFIG_X86_X2APIC
        if (x2apic_enabled()) {
                /*
                 * We do not have access to IR inside Jailhouse 
non-root cells.
@@ -79,6 +80,7 @@ static void __init jailhouse_get_smp_config(unsigned 
int early)
                 */
                default_acpi_madt_oem_check("", "");
        }
+#endif

        register_lapic_address(0xfee00000);

>        Arnd