Re: [PATCH v3] enable x2APIC without interrupt remapping under KVM

Gleb Natapov
2009-06-29T15:10:15Z

On Mon, Jun 29, 2009 at 07:58:39AM -0700, Suresh Siddha wrote:
> On Mon, 2009-06-29 at 06:29 -0700, Gleb Natapov wrote:
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index d1430ef..3e5b6ea 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -260,12 +260,15 @@ config SMP
> >
> > config X86_X2APIC
> > bool "Support x2apic"
> > - depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
> > + depends on X86_LOCAL_APIC && X86_64
>
> Thinking more, probably we shouldn't remove this dependency. This might
> encourage people (knowingly or unknowingly) to enable x2apic without
> interrupt-remapping. Can we remove this? KVM mode will still work even
> if we fail to enable interrupt-remapping. So this shouldn't be an issue,
> correct?
>
Yes, KVM will still work. I don't have strong fillings one way or the
other, but why mandate an option that is no longer mandatory. What
others think?

> Sorry I should have commented about this before.
>
> >
> > ioapic_entries = alloc_ioapic_entries();
> > if (!ioapic_entries) {
> > - pr_info("Allocate ioapic_entries failed: %d\n", ret);
> > - goto end;
> > + pr_info("Allocate ioapic_entries failed\n");
> > + return;
>
>
> We should go to ir_failed ..
Why? There is not more ir_failed.

>
> > }
> >
> > ret = save_IO_APIC_setup(ioapic_entries);
> > if (ret) {
> > pr_info("Saving IO-APIC state failed: %d\n", ret);
> > - goto end;
> > + free_ioapic_entries(ioapic_entries);
> > + return;
>
> same here.
>
Why? What ir_failed should do? Call free_ioapic_entries(ioapic_entries)
and exit?

--
Gleb.