Re: [RFC PATCH v3 3/6] KVM: Rename invalidate_begin to invalidate_start for consistency

[Sean Christopherson <seanjc@google.com>]

On Tue, Mar 10, 2026, Takahiro Itazuri wrote:
> Most MMU-related helpers use "_start" suffix.  Align with the prevailing
> naming convention for consistency across MMU-related codebase.
> 
> ```
> $ git grep -E "invalidate(_range)?_start" | wc -l
> 123
> 
> $ git grep -E "invalidate(_range)?_begin" | wc -l
> 14
> ```

I'm a-ok with the change, but the changelog should make it clear to what KVM is
conforming.  Very specifically, IMO, all that really matters here is aligning with
mmu_notifier_ops.invalidate_range_start().

Because for me, "MMU-related" anything in the context of KVM means just that,
KVM's MMU code.  I don't care what other MMU-related code outside of KVM uses for
naming, if that code doesn't interact with KVM in any way.  And for KVM specifically,
it's a much closer race.

  $ git grep -E "invalidate(_range)?_begin"  **/kvm | wc -l
  11
  $ git grep -E "invalidate(_range)?_start"  **/kvm | wc -l
  16

But as above, I'm definitely in favor of matching mmu_notifier_ops.invalidate_range_start().

> No functional change intended.
> 
> Signed-off-by: Takahiro Itazuri <itazur@amazon.com>
> ---
>  arch/x86/kvm/mmu/mmu.c       |  2 +-
>  include/linux/kvm_host.h     |  2 +-
>  include/linux/mmu_notifier.h |  4 ++--
>  virt/kvm/guest_memfd.c       | 14 +++++++-------
>  virt/kvm/kvm_main.c          |  6 +++---
>  5 files changed, 14 insertions(+), 14 deletions(-)

...

> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 2ea5d2f172f7..618a71894ed1 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -1566,7 +1566,7 @@ void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc);
>  void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc);
>  #endif
>  
> -void kvm_mmu_invalidate_begin(struct kvm *kvm);
> +void kvm_mmu_invalidate_start(struct kvm *kvm);
>  void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end);
>  void kvm_mmu_invalidate_end(struct kvm *kvm);
>  bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range);
> diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
> index d1094c2d5fb6..8ecf36a84e3b 100644
> --- a/include/linux/mmu_notifier.h
> +++ b/include/linux/mmu_notifier.h
> @@ -134,8 +134,8 @@ struct mmu_notifier_ops {
>  	 * Invalidation of multiple concurrent ranges may be
>  	 * optionally permitted by the driver. Either way the
>  	 * establishment of sptes is forbidden in the range passed to
> -	 * invalidate_range_begin/end for the whole duration of the
> -	 * invalidate_range_begin/end critical section.
> +	 * invalidate_range_start/end for the whole duration of the
> +	 * invalidate_range_start/end critical section.
>  	 *
>  	 * invalidate_range_start() is called when all pages in the
>  	 * range are still mapped and have at least a refcount of one.

Please move the include/linux/mmu_notifier.h change to its own standalone patch,
as in, not even part of this series.  It's an obviously correct change (the comment
has been wrong since commit cddb8a5c14aa ("mmu-notifiers: core")) and has nothing
to do with KVM.