diff mbox series

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

Message ID 20231027182217.3615211-6-seanjc@google.com (mailing list archive)
State Handled Elsewhere
Headers show
Series KVM: guest_memfd() and per-page attributes | expand

Commit Message

Sean Christopherson Oct. 27, 2023, 6:21 p.m. UTC
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@google.com>
---
 arch/powerpc/kvm/powerpc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Paolo Bonzini Oct. 30, 2023, 4:34 p.m. UTC | #1
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@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@redhat.com>
Fuad Tabba Nov. 1, 2023, 12:51 p.m. UTC | #2
On Fri, Oct 27, 2023 at 7:22 PM Sean Christopherson <seanjc@google.com> 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@google.com>
> ---

Reviewed-by: Fuad Tabba <tabba@google.com>

Cheers,
/fuad

>  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
> --
> 2.42.0.820.g83a721a137-goog
>
diff mbox series

Patch

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