+#ifdef CONFIG_MIGRATION
+static int shmem_migrate_page(struct address_space *mapping,
+ struct page *newpage, struct page *page,
+ enum migrate_mode mode)
+{
+ struct inode *inode = mapping->host;
+ struct shmem_inode_info *info = SHMEM_I(inode);
+
+ if (info->memfile_node.flags & MEMFILE_F_UNMOVABLE)
+ return -EOPNOTSUPP;
+ return migrate_page(mapping, newpage, page, mode);
Wondering how well page migrate would work for private pages
on shmem memfd based backend?
From high level:
- KVM unset MEMFILE_F_UNMOVABLE bit to indicate it capable of
migrating a page.
- Introduce new 'migrate' callback(s) to memfile_notifier_ops for KVM
to register.
- The callback is hooked to migrate_page() here.
- Once page migration requested, shmem calls into the 'migrate'
callback(s) to perform additional steps for encrypted memory (For
TDX we will call TDH.MEM.PAGE.RELOCATE).