Re: [PATCH v1 2/4] KVM: x86: Introduce MSR read/write emulation helpers

[Xin Li]

> > > > +
> > > > 		handled = !handle_fastpath_set_x2apic_icr_irqoff(vcpu, data);
> > > > 		break;
> > > > 	case MSR_IA32_TSC_DEADLINE:
> > > > -		data = kvm_read_edx_eax(vcpu);
> > > > +		if (reg == VCPU_EXREG_EDX_EAX)
> > > > +			data = kvm_read_edx_eax(vcpu);
> > > > +		else
> > > > +			data = kvm_register_read(vcpu, reg);
> > > > +
> > >
> > > Hoist this chunk out of the switch clause to avoid duplication.
> >
> > I thought about it, but didn't do so because the original code doesn't read
> > the MSR data from registers when a MSR is not being handled in the
> > fast path, which saves some cycles in most cases.
>
> Can you hold off on doing anything with this series?  Mostly to save your time.

Sure.

> Long story short, I unexpectedly dove into the fastpath code this week while sorting
> out an issue with the mediated PMU series, and I ended up with a series of patches
> to clean things up for both the mediated PMU series and for this series.
>
> With luck, I'll get the cleanups, the mediated PMU series, and a v2 of this series
> posted tomorrow (I also have some feedback on VCPU_EXREG_EDX_EAX; we can avoid it
> entirely without much fuss).

Will wait and take a look when you post them.