[PATCH v13 05/35] KVM: PPC: Drop dead code related to KVM_ARCH_WANT_MMU_NOTIFIER

[Paolo Bonzini]

On 10/27/23 20:21, Sean Christopherson wrote:
> Assert that both KVM_ARCH_WANT_MMU_NOTIFIER and CONFIG_MMU_NOTIFIER are
> defined when KVM is enabled, and return '1' unconditionally for the
> CONFIG_KVM_BOOK3S_HV_POSSIBLE=n path.  All flavors of PPC support for KVM
> select MMU_NOTIFIER, and KVM_ARCH_WANT_MMU_NOTIFIER is unconditionally
> defined by arch/powerpc/include/asm/kvm_host.h.
> 
> Effectively dropping use of KVM_ARCH_WANT_MMU_NOTIFIER will simplify a
> future cleanup to turn KVM_ARCH_WANT_MMU_NOTIFIER into a Kconfig, i.e.
> will allow combining all of the
> 
>    #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
> 
> checks into a single
> 
>    #ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
> 
> without having to worry about PPC's "bare" usage of
> KVM_ARCH_WANT_MMU_NOTIFIER.
> 
> Signed-off-by: Sean Christopherson <seanjc at google.com>
> ---
>   arch/powerpc/kvm/powerpc.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 7197c8256668..b0a512ede764 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -632,12 +632,13 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>   		break;
>   #endif
>   	case KVM_CAP_SYNC_MMU:
> +#if !defined(CONFIG_MMU_NOTIFIER) || !defined(KVM_ARCH_WANT_MMU_NOTIFIER)
> +		BUILD_BUG();
> +#endif
>   #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
>   		r = hv_enabled;
> -#elif defined(KVM_ARCH_WANT_MMU_NOTIFIER)
> -		r = 1;
>   #else
> -		r = 0;
> +		r = 1;
>   #endif
>   		break;
>   #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE

Reviewed-by: Paolo Bonzini <pbonzini at redhat.com>