Re: [PATCH v19 09/20] KVM: arm64: Add VM specific callback for S2 MMU operations

[Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>]

On Sun, 20 Sep 2026 22:28:34 +0100
Suzuki K Poulose <suzuki.poulose@arm.com> wrote:

> Add VM type specific S2 MMU operation backends which can be initialized per
> VM flavor, to keep the handling cleaner.
> 
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

A small suggestion inline that makes it explicit when there isn't
range operation and a full flush of tlb is needed.

I don't mind either way, but thought I'd mention it anyway in case
you hadn't already dismissed it.

Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>


> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 03f2017a7404a..d97a4a1bca23f 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -37,6 +37,8 @@ static unsigned long __ro_after_init io_map_base;
>  
>  #define KVM_PGT_FN(fn)		(!is_protected_kvm_enabled() ? fn : p ## fn)
>  

>  /**
>   * kvm_arch_flush_remote_tlbs() - flush all VM TLB entries for v7/8
>   * @kvm:	pointer to kvm structure.
> @@ -174,26 +188,36 @@ static bool memslot_is_logging(struct kvm_memory_slot *memslot)
>   */
>  int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
>  {
> -	if (is_protected_kvm_enabled())
> -		kvm_call_hyp_nvhe(__pkvm_tlb_flush_vmid, kvm->arch.pkvm.handle);
> -	else
> -		kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
> -	return 0;
> +	if (!kvm->arch.vm_s2_ops->vm_flush_remote_tlbs)
> +		return 1;

For consistency with other cases and because it looks nicer
blank line here.

> +	return kvm->arch.vm_s2_ops->vm_flush_remote_tlbs(kvm);
>  }
>  
> -int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm,
> -				      gfn_t gfn, u64 nr_pages)
> +static int pkvm_flush_remote_tlbs_range(struct kvm *kvm,
> +					gfn_t gfn, u64 nr_pages)
> +{
> +	return pkvm_flush_remote_tlbs(kvm);

For the cases where there isn't a range call, perhaps you should just
not provide the op and have the wrapper fall back to
calling the 'flush all' variant if there is no range one available?

> +}