Re: [PATCH 2/6] KVM: x86: decouple irqchip_in_kernel() and pic_irqchip()

[Paolo Bonzini <pbonzini@redhat.com>]

----- Original Message -----
> From: "Radim Krčmář" <rkrcmar@redhat.com>
> To: "Paolo Bonzini" <pbonzini@redhat.com>
> Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
> Sent: Thursday, November 24, 2016 6:21:04 PM
> Subject: Re: [PATCH 2/6] KVM: x86: decouple irqchip_in_kernel() and pic_irqchip()
> 
> 2016-11-24 11:55-0500, Paolo Bonzini:
> >> irqchip_in_kernel() tried to save a bit by reusing pic_irqchip(), but it
> >> just complicated the code.
> >> Add kvm->arch.irqchip_kvm that matches kvm->arch.irqchip_split.
> >> (Turning them into an exclusive type would be nicer.)
> > 
> > Then do it. ;)
> 
> It is hard to name! :)
> 
> I would squash something like this if the names were ok:
> 
> diff --git a/arch/x86/include/asm/kvm_host.h
> b/arch/x86/include/asm/kvm_host.h
> index 929228ec2839..726235f0e3f3 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -706,6 +706,12 @@ struct kvm_hv {
>  	HV_REFERENCE_TSC_PAGE tsc_ref;
>  };
>  
> +enum kvm_kernel_irqchip {

kvm_kernel_irqchip_mode?

> +	KVM_IRQCHIP_NONE,
> +	KVM_IRQCHIP_KVM,          /* created in KVM_CREATE_IRQCHIP */
> +	KVM_IRQCHIP_SPLIT,        /* created in KVM_CAP_SPLIT_IRQCHIP */

Since you pretty much asked to nitpick, KVM_IRQCHIP_KERNEL would
match irqchip_in_kernel better.  Also, s/in/with/? :)

> +};
> +
>  struct kvm_arch {
>  	unsigned int n_used_mmu_pages;
>  	unsigned int n_requested_mmu_pages;
> @@ -778,8 +784,7 @@ struct kvm_arch {
>  
>  	u64 disabled_quirks;
>  
> -	bool irqchip_kvm;
> -	bool irqchip_split;
> +	enum kvm_kernel_irqchip irqchip;

irqchip_mode?

>  	u8 nr_reserved_ioapic_pins;
>  
>  	bool disabled_lapic_found;
> diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h
> index a80515e38645..f90ca9e0affc 100644
> --- a/arch/x86/kvm/irq.h
> +++ b/arch/x86/kvm/irq.h
> @@ -93,12 +93,12 @@ static inline int pic_in_kernel(struct kvm *kvm)
>  
>  static inline int irqchip_split(struct kvm *kvm)
>  {
> -	return kvm->arch.irqchip_split;
> +	return kvm->arch.irqchip == KVM_IRQCHIP_SPLIT;
>  }
>  
>  static inline int irqchip_kvm(struct kvm *kvm)
>  {
> -	return kvm->arch.irqchip_kvm;
> +	return kvm->arch.irqchip == KVM_IRQCHIP_KVM;
>  }
>  
>  static inline int irqchip_in_kernel(struct kvm *kvm)
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 4c364a13b17c..99c63b73dd35 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3834,7 +3834,7 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
>  			goto split_irqchip_unlock;
>  		/* Pairs with irqchip_in_kernel. */
>  		smp_wmb();
> -		kvm->arch.irqchip_split = true;
> +		kvm->arch.irqchip = KVM_IRQCHIP_SPLIT;
>  		kvm->arch.nr_reserved_ioapic_pins = cap->args[0];
>  		r = 0;
>  split_irqchip_unlock:
> @@ -3931,7 +3931,7 @@ long kvm_arch_vm_ioctl(struct file *filp,
>  		}
>  		/* Write kvm->irq_routing before enabling irqchip_in_kernel. */
>  		smp_wmb();
> -		kvm->arch.irqchip_kvm = true;
> +		kvm->arch.irqchip = KVM_IRQCHIP_KVM;
>  	create_irqchip_unlock:
>  		mutex_unlock(&kvm->lock);
>  		break;
>