On Wed, Jun 03, 2026 at 11:17:33PM +0800, Guanghui Feng wrote:
> +phys_addr_t iommu_iova_to_phys_length(struct iommu_domain *domain,
> + dma_addr_t iova,
> + size_t *mapped_length)
> {
This should take in an ending point so the accumulation knows when to
stop, otherwise it is too hard to use.
> - if (domain->type == IOMMU_DOMAIN_IDENTITY)
> + phys_addr_t phys;
> +
> + if (domain->type == IOMMU_DOMAIN_IDENTITY) {
> + if (mapped_length)
> + *mapped_length = PAGE_SIZE;
> return iova;
> + }
>
> - if (domain->type == IOMMU_DOMAIN_BLOCKED)
> - return 0;
> + if (mapped_length)
> + *mapped_length = 0;
> +
> + if (domain->ops->iova_to_phys_length)
> + return domain->ops->iova_to_phys_length(domain, iova,
> mapped_length);
> +
> + /* Fallback to legacy iova_to_phys without length info */
> + if (!domain->ops->iova_to_phys)
> + return PHYS_ADDR_MAX;
> +
> + phys = domain->ops->iova_to_phys(domain, iova);
> + if (!phys)
> + return PHYS_ADDR_MAX;
And to properly clean up the callers all the non-iommupt paths should
manually do accumulation here as well.
Basically if you call this function you get a maximal contiguous
physical range as efficiently as possible.
Jason
