[PATCH 04/20] KVM: arm64: Use block-level annotations when setting up the host stage-2

[Wei-Lin Chang]

On Mon, Aug 03, 2026 at 11:08:48AM +0100, Vincent Donnefort wrote:

[...]

> +static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx,
> +				     enum kvm_pgtable_walk_flags visit)
> +{
> +	struct fix_host_ownership_data *data = ctx->arg;
> +	enum kvm_pgtable_prot prot = 0;
> +	phys_addr_t phys = 0;
> +	int ret;
> +
> +	if (kvm_pte_valid(ctx->old))
> +		prot = kvm_pgtable_hyp_pte_prot(ctx->old);
> +
> +	if (!prot) {
> +		/* Unchanged region */
> +		if (!data->prot)
> +			return 0;
> +
> +		goto apply_ownership;
> +	}
> +
> +	phys = kvm_pte_to_phys(ctx->old);
> +	if (!addr_is_memory(phys))
> +		return -EINVAL;
> +
> +	/* We already know phys is contiguous as we walk the linear map */
> +
> +	if (prot != data->prot)
> +		goto apply_ownership;
> +
> +	/* Accumulate in the current region */
> +	data->size += kvm_granule_size(ctx->level);
> +
> +	return 0;
> +
> +apply_ownership:
> +	ret = __fix_host_ownership(data);
> +	if (ret)
> +		return ret;
> +
> +	data->phys = phys;
> +	data->size = kvm_granule_size(ctx->level);
> +	data->prot = prot;
> +
> +	return 0;
> +}

I think this function can be simplified, if we check phys first:

static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx,
				     enum kvm_pgtable_walk_flags visit)
{
	struct fix_host_ownership_data *data = ctx->arg;
	enum kvm_pgtable_prot prot = 0;
	phys_addr_t phys = 0;
	int ret;

	if (kvm_pte_valid(ctx->old))
		prot = kvm_pgtable_hyp_pte_prot(ctx->old);

	if (prot) {
		phys = kvm_pte_to_phys(ctx->old);
		if (!addr_is_memory(phys))
			return -EINVAL;
	}

	if (prot != data->prot) {
		ret = __fix_host_ownership(data);
		if (ret)
			return ret;

		data->phys = phys;
		data->size = kvm_granule_size(ctx->level);
		data->prot = prot;
	} else {
		data->size += kvm_granule_size(ctx->level);
	}
	return 0;
}

Did I miss anything?

Thanks,
Wei-Lin Chang