Re: [Xen-devel] [PATCH v3 05/16] x86/VPMU: Handle APIC_LVTPC accesses

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 01/13/2014 08:28 AM, Jan Beulich wrote:
> > > > On 06.01.14 at 20:24, Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> wrote:
> > Update APIC_LVTPC vector when HVM guest writes to it.
> >
> > Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
...

> > +void vpmu_lvtpc_update(uint32_t val)
> > +{
> > +    struct vpmu_struct *vpmu = vcpu_vpmu(current);
> > +
> > +    vpmu->hw_lapic_lvtpc = PMU_APIC_VECTOR | (val & APIC_LVT_MASKED);
> > +    apic_write(APIC_LVTPC, vpmu->hw_lapic_lvtpc);
> > +}
> > +
> >   int vpmu_do_wrmsr(unsigned int msr, uint64_t msr_content)
> >   {
> >       struct vpmu_struct *vpmu = vcpu_vpmu(current);
> > @@ -227,19 +235,21 @@ void vpmu_initialise(struct vcpu *v)
> >       case X86_VENDOR_AMD:
> >           if ( svm_vpmu_initialise(v, opt_vpmu_enabled) != 0 )
> >               opt_vpmu_enabled = 0;
> > -        break;
> > +        return;
> >   
> >       case X86_VENDOR_INTEL:
> >           if ( vmx_vpmu_initialise(v, opt_vpmu_enabled) != 0 )
> >               opt_vpmu_enabled = 0;
> > -        break;
> > +        return;
> >   
> >       default:
> >           printk("VPMU: Initialization failed. "
> >                  "Unknown CPU vendor %d\n", vendor);
> >           opt_vpmu_enabled = 0;
> > -        break;
> > +        return;
> >       }
> > +
> > +    vpmu->hw_lapic_lvtpc = PMU_APIC_VECTOR | APIC_LVT_MASKED;
> >   }
> So what is this good for? All code paths above use "return" now,
> hence how would execution get here?
Yes, it shouldn't be here. I could move it up but since we are now 
updating LVTPC explicitly when a guest is writing APIC I think I can 
just drop it altogether.
-boris

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel