On Sun, Aug 05, 2012 at 05:35:21PM +0300, Avi Kivity wrote:
> On 08/05/2012 03:58 PM, Gleb Natapov wrote:
> > Usually all APICs are HW enabled so the check can be optimized out.
> >
> > Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
> > ---
> > arch/x86/kvm/lapic.c | 29 ++++++++++++++++++++++++++++-
> > arch/x86/kvm/lapic.h | 1 +
> > arch/x86/kvm/x86.c | 1 +
> > 3 files changed, 30 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> > index c3f14fe..1aa5528 100644
> > --- a/arch/x86/kvm/lapic.c
> > +++ b/arch/x86/kvm/lapic.c
> > @@ -34,6 +34,7 @@
> > #include <asm/current.h>
> > #include <asm/apicdef.h>
> > #include <linux/atomic.h>
> > +#include <linux/jump_label.h>
> > #include "kvm_cache_regs.h"
> > #include "irq.h"
> > #include "trace.h"
> > @@ -117,9 +118,13 @@ static inline int __apic_test_and_clear_vector(int vec, void *bitmap)
> > return __test_and_clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
> > }
> >
> > +struct static_key_deferred apic_hw_disabled __read_mostly;
>
> On top of file please. Add all_ to the name to make it clear we're
> talking about all apics.
>
This is count of disabled apics really. So I think all_apic_hw_disabled
is misleading.
> > +
> > static inline int apic_hw_enabled(struct kvm_lapic *apic)
> > {
> > - return (apic)->vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE;
> > + if (static_key_false(&apic_hw_disabled.key))
> > + return apic->vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE;
>
> Hm, for the test to be readable, it needs to be
>
> if (static_key_false(&all_apics_hw_enabled))
>
Exactly. all_ makes it so because apic_hw_disabled is a counter that
counts disabled apics. So may be call it global_hw_disabled_apic_counter?
--
Gleb.
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