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

[Suzuki K Poulose]

On 22/09/2026 23:29, Jonathan Cameron wrote:
> On Sun, 20 Sep 2026 22:28:34 +0100
> Suzuki K Poulose <suzuki.poulose@xxxxxxx> 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@xxxxxxx>
>
> 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@xxxxxxxxxxxxxxxx>
>
>
> > 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.

Ack

> > +	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?

The core KVM falls back to flushing all TLBs if the range one
returns true anyways. So, I would leave it as it is.

Cheers
Suzuki


> > +}