On Wed, Sep 13, 2023 at 06:55:12PM -0700, Sean Christopherson wrote:
> +static struct folio *kvm_gmem_get_folio(struct file *file, pgoff_t index)
> +{
> + struct folio *folio;
> +
> + /* TODO: Support huge pages. */
> + folio = filemap_grab_folio(file->f_mapping, index);
> + if (IS_ERR_OR_NULL(folio))
> + return NULL;
> +
> + /*
> + * Use the up-to-date flag to track whether or not the memory has been
> + * zeroed before being handed off to the guest. There is no backing
> + * storage for the memory, so the folio will remain up-to-date until
> + * it's removed.
> + *
> + * TODO: Skip clearing pages when trusted firmware will do it when
> + * assigning memory to the guest.
> + */
> + if (!folio_test_uptodate(folio)) {
> + unsigned long nr_pages = folio_nr_pages(folio);
> + unsigned long i;
> +
> + for (i = 0; i < nr_pages; i++)
> + clear_highpage(folio_page(folio, i));
> +
> + folio_mark_uptodate(folio);
> + }
> +
> + /*
> + * Ignore accessed, referenced, and dirty flags. The memory is
> + * unevictable and there is no storage to write back to.
> + */
> + return folio;
> +}
If VFIO wants to map a private page, is it required to call this function for PFN?
