Re: [PATCH] KVM: X86: Call kvm_x86_ops.cpuid_update() after CPUIDs fully updated

[Xiaoyao Li]

On 5/29/2020 12:15 AM, Paolo Bonzini wrote:
> On 28/05/20 17:40, Xiaoyao Li wrote:
> > > > kvm_x86_ops.cpuid_update() is used to update vmx/svm settings based on
> > > > updated CPUID settings. So it's supposed to be called after CPUIDs are
> > > > fully updated, not in the middle stage.
> > > >
> > > > Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> > >
> > > Are you seeing anything bad happening from this?
> >
> > Not yet.
> >
> > IMO changing the order is more reasonable and less confusing.
>
> Indeed, I just could not decide whether to include it in 5.7 or not.

Maybe for 5.8

I have a new idea to refactor a bit more that I find it does three 
things in kvm_update_cpuid():
- update cpuid;
- update vcpu states, e.g., apic->lapic_timer.timer_mode_mask, 
guest_supported_xcr0, maxphyaddr, ... etc,
- cpuid check, for vaddr_bits

I'm going to split it, and make the order as:
1. kvm_check_cpuid(), if invalid value return error;
2. kvm_update_cpuid();
3. kvm_update_state_based_on_cpuid();
   and kvm_x86_ops.kvm_x86_ops.cpuid_update() can be called inside it.

If you feel OK, I'll do it tomorrow.

-Xiaoyao