Re: [RFC PATCH 27/39] KVM: guest_memfd: Allow mmapping guest_memfd files

On Tue, Sep 10, 2024 at 11:43:58PM +0000, Ackerley Tng wrote:

@@ -790,6 +791,9 @@ static long kvm_gmem_punch_hole(struct inode *inode, loff_t offset, loff_t len) */ filemap_invalidate_lock(inode->i_mapping);

• /* TODO: Check if even_cows should be 0 or 1 */
• unmap_mapping_range(inode->i_mapping, start, len, 0);
• list_for_each_entry(gmem, gmem_list, entry) kvm_gmem_invalidate_begin(gmem, start, end);

@@ -946,6 +950,9 @@ static void kvm_gmem_hugetlb_teardown(struct inode *inode) { struct kvm_gmem_hugetlb *hgmem;

• /* TODO: Check if even_cows should be 0 or 1 */
• unmap_mapping_range(inode->i_mapping, 0, LLONG_MAX, 0);

Setting to 0 is ok in both places: even_cows only applies to MAP_PRIVATE, which gmemfd doesn't support. So feel free to drop the two comment lines.

Thanks,