Re: [PATCH v2 1/2] KVM: arm64: Resume stage-2 teardown where the walk stopped

[Oliver Upton <oupton@kernel.org>]

Hi Fuad,

On Wed, Nov 04, 2026 at 12:44:50PM +0000, Fuad Tabba wrote:
> +u64 kvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt,
> +				     u64 addr, u64 size)

Returning a signed value here would be a good idea so you can percolate
walk failures back up to the caller. Since that WARN_ON() below may as
well be a BUG_ON() in hyp code.

Otherwise, rest looks good.

Thanks,
Oliver

>  {
>  	struct kvm_pgtable_walker walker = {
>  		.cb	= stage2_free_walker,
>  		.flags	= KVM_PGTABLE_WALK_LEAF |
>  			  KVM_PGTABLE_WALK_TABLE_POST,
>  	};
> +	struct kvm_pgtable_walk_data data = {
> +		.walker	= &walker,
> +		.start	= addr,
> +		.addr	= addr,
> +		.end	= addr + size,
> +	};
>  
> -	WARN_ON(kvm_pgtable_walk(pgt, addr, size, &walker));
> +	if (WARN_ON(_kvm_pgtable_walk(pgt, &data)))
> +		return addr + size;
> +
> +	return data.addr;
>  }
>  
>  void kvm_pgtable_stage2_destroy_pgd(struct kvm_pgtable *pgt)
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 1db10d8d6db73..4f1adadeffb8b 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -1011,8 +1011,8 @@ static void stage2_destroy_range(struct kvm_pgtable *pgt, phys_addr_t addr,
>  
>  	do {
>  		next = stage2_range_addr_end(addr, end);
> -		KVM_PGT_FN(kvm_pgtable_stage2_destroy_range)(pgt, addr,
> -							     next - addr);
> +		next = KVM_PGT_FN(kvm_pgtable_stage2_destroy_range)(pgt, addr, next - addr);
> +		next = min(next, end);
>  		if (next != end)
>  			cond_resched();
>  	} while (addr = next, addr != end);
> diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
> index 016997288fd23..f21c3326dda68 100644
> --- a/arch/arm64/kvm/pkvm.c
> +++ b/arch/arm64/kvm/pkvm.c
> @@ -499,14 +499,14 @@ static int __pkvm_pgtable_stage2_unshare(struct kvm_pgtable *pgt, u64 start, u64
>  	return 0;
>  }
>  
> -void pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt,
> -					u64 addr, u64 size)
> +u64 pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt,
> +				      u64 addr, u64 size)
>  {
>  	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
>  	pkvm_handle_t handle = kvm->arch.pkvm.handle;
>  
>  	if (!handle)
> -		return;
> +		return addr + size;
>  
>  	if (pkvm_hyp_vm_is_created(kvm) && !kvm->arch.pkvm.is_dying) {
>  		WARN_ON(kvm_call_hyp_nvhe(__pkvm_start_teardown_vm, handle));
> @@ -517,6 +517,8 @@ void pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt,
>  		__pkvm_pgtable_stage2_reclaim(pgt, addr, addr + size);
>  	else
>  		__pkvm_pgtable_stage2_unshare(pgt, addr, addr + size);
> +
> +	return addr + size;
>  }
>  
>  void pkvm_pgtable_stage2_destroy_pgd(struct kvm_pgtable *pgt)
> -- 
> 2.47.3
>