2023-10-27 18:24:48

by Sean Christopherson

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

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 <[email protected]>
---
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

2023-10-30 16:36:38

by Paolo Bonzini

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

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 <[email protected]>
> ---
> 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 <[email protected]>

2023-11-01 12:52:18

by Fuad Tabba

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

On Fri, Oct 27, 2023 at 7:22 PM Sean Christopherson <[email protected]> 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 <[email protected]>
> ---

Reviewed-by: Fuad Tabba <[email protected]>

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
>