Re: [PATCH 36/44] KVM: x86: Do compatibility checks when onlining CPU

[Isaku Yamahata]

On Thu, Nov 03, 2022 at 10:34:10PM +0000,
Sean Christopherson <seanjc@xxxxxxxxxx> wrote:

> On Thu, Nov 03, 2022, Isaku Yamahata wrote:
> > On Wed, Nov 02, 2022 at 11:19:03PM +0000,
> > Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
> > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> > > index f223c845ed6e..c99222b71fcc 100644
> > > --- a/arch/x86/include/asm/kvm_host.h
> > > +++ b/arch/x86/include/asm/kvm_host.h
> > > @@ -1666,7 +1666,7 @@ struct kvm_x86_nested_ops {
> > >  };
> > >  
> > >  struct kvm_x86_init_ops {
> > > -	int (*check_processor_compatibility)(void);
> > > +	int (*check_processor_compatibility)(int cpu);
> > 
> > Is this cpu argument used only for error message to include cpu number
> > with avoiding repeating raw_smp_processor_id() in pr_err()?
> 
> Yep.
> 
> > The actual check is done on the current executing cpu.
> > 
> > If cpu != raw_smp_processor_id(), cpu is wrong. Although the function is called
> > in non-preemptive context, it's a bit confusing. So voting to remove it and
> > to use.
> 
> What if I rename the param is this_cpu?  I 100% agree the argument is confusing
> as-is, but forcing all the helpers to manually grab the cpu is quite annoying.

Makes sense. Let's settle it with this_cpu.
-- 
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>