On Wednesday, July 19, 2023 7:45 AM, Sean Christopherson wrote:
> +int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
> + gfn_t gfn, kvm_pfn_t *pfn, int *max_order) {
> + pgoff_t index = gfn - slot->base_gfn + slot->gmem.pgoff;
> + struct kvm_gmem *gmem;
> + struct folio *folio;
> + struct page *page;
> + struct file *file;
> +
> + file = kvm_gmem_get_file(slot);
> + if (!file)
> + return -EFAULT;
> +
> + gmem = file->private_data;
> +
> + if (WARN_ON_ONCE(xa_load(&gmem->bindings, index) != slot)) {
> + fput(file);
> + return -EIO;
> + }
> +
> + folio = kvm_gmem_get_folio(file_inode(file), index);
> + if (!folio) {
> + fput(file);
> + return -ENOMEM;
> + }
> +
> + page = folio_file_page(folio, index);
> +
> + *pfn = page_to_pfn(page);
> + *max_order = compound_order(compound_head(page));
Maybe better to check if caller provided a buffer to get the max_order:
if (max_order)
*max_order = compound_order(compound_head(page));
This is what the previous version did (restrictedmem_get_page),
so that callers who only want to get a pfn don't need to define
an unused "order" param.
