On Tue, May 12, 2026 at 12:24:08AM +0800, Yu Zhang wrote:
> +static inline u16 hv_iommu_fill_iova_list(union hv_iommu_flush_va *iova_list,
> + unsigned long start,
> + unsigned long end)
> +{
> + unsigned long start_pfn = start >> PAGE_SHIFT;
> + unsigned long end_pfn = PAGE_ALIGN(end) >> PAGE_SHIFT;
> + unsigned long nr_pages = end_pfn - start_pfn;
> + u16 count = 0;
> +
> + while (nr_pages > 0) {
> + unsigned long flush_pages;
> + int order;
> + unsigned long pfn_align;
> + unsigned long size_align;
> +
> + if (count >= HV_IOMMU_MAX_FLUSH_VA_COUNT) {
> + count = HV_IOMMU_FLUSH_VA_OVERFLOW;
> + break;
> + }
> +
> + if (start_pfn)
> + pfn_align = __ffs(start_pfn);
> + else
> + pfn_align = BITS_PER_LONG - 1;
> +
> + size_align = __fls(nr_pages);
> + order = min(pfn_align, size_align);
> + iova_list[count].page_mask_shift = order;
> + iova_list[count].page_number = start_pfn;
> +
> + flush_pages = 1UL << order;
> + start_pfn += flush_pages;
> + nr_pages -= flush_pages;
> + count++;
> + }
This seems like a really silly hypervisor interface. Why doesn't it
just accept a normal range? Splitting it into power of two aligned
ranges is very inefficient.
Jason
