On 7/13/25 19:43, Shivank Garg wrote:
> Add dedicated inode structure (kvm_gmem_inode_info) and slab-allocated
> inode cache for guest memory backing, similar to how shmem handles inodes.
>
> This adds the necessary allocation/destruction functions and prepares
> for upcoming guest_memfd NUMA policy support changes.
>
> Signed-off-by: Shivank Garg <shivankg@xxxxxxx>
> ---
> virt/kvm/guest_memfd.c | 58 ++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 56 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index dabcc2317291..989e2b26b344 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -17,6 +17,15 @@ struct kvm_gmem {
> struct list_head entry;
> };
>
> +struct kvm_gmem_inode_info {
> + struct inode vfs_inode;
> +};
> +
> +static inline struct kvm_gmem_inode_info *KVM_GMEM_I(struct inode *inode)
> +{
> + return container_of(inode, struct kvm_gmem_inode_info, vfs_inode);
> +}
> +
> /**
> * folio_file_pfn - like folio_file_page, but return a pfn.
> * @folio: The folio which contains this index.
> @@ -392,8 +401,33 @@ static struct file_operations kvm_gmem_fops = {
> .fallocate = kvm_gmem_fallocate,
> };
>
> +static struct kmem_cache *kvm_gmem_inode_cachep;
> +
> +static struct inode *kvm_gmem_alloc_inode(struct super_block *sb)
> +{
> + struct kvm_gmem_inode_info *info;
> +
> + info = alloc_inode_sb(sb, kvm_gmem_inode_cachep, GFP_KERNEL);
> + if (!info)
> + return NULL;
> +
> + return &info->vfs_inode;
> +}
> +
> +static void kvm_gmem_destroy_inode(struct inode *inode)
> +{
> +}
> +
> +static void kvm_gmem_free_inode(struct inode *inode)
> +{
> + kmem_cache_free(kvm_gmem_inode_cachep, KVM_GMEM_I(inode));
> +}
> +
> static const struct super_operations kvm_gmem_super_operations = {
> .statfs = simple_statfs,
> + .alloc_inode = kvm_gmem_alloc_inode,
> + .destroy_inode = kvm_gmem_destroy_inode,
> + .free_inode = kvm_gmem_free_inode,
> };
>
> static int kvm_gmem_init_fs_context(struct fs_context *fc)
> @@ -426,17 +460,37 @@ static int kvm_gmem_init_mount(void)
> return 0;
> }
>
> +static void kvm_gmem_init_inode(void *foo)
> +{
> + struct kvm_gmem_inode_info *info = foo;
> +
> + inode_init_once(&info->vfs_inode);
> +}
> +
> int kvm_gmem_init(struct module *module)
> {
> - kvm_gmem_fops.owner = module;
> + int ret;
>
> - return kvm_gmem_init_mount();
> + kvm_gmem_fops.owner = module;
> + kvm_gmem_inode_cachep = kmem_cache_create("kvm_gmem_inode_cache",
> + sizeof(struct kvm_gmem_inode_info),
> + 0, SLAB_ACCOUNT,
> + kvm_gmem_init_inode);
Since this is new code, please use the new variant of kmem_cache_create()
that takes the args parameter.
> + if (!kvm_gmem_inode_cachep)
> + return -ENOMEM;
> + ret = kvm_gmem_init_mount();
> + if (ret) {
> + kmem_cache_destroy(kvm_gmem_inode_cachep);
> + return ret;
> + }
> + return 0;
> }
>
> void kvm_gmem_exit(void)
> {
> kern_unmount(kvm_gmem_mnt);
> kvm_gmem_mnt = NULL;
> + kmem_cache_destroy(kvm_gmem_inode_cachep);
> }
>
> static int kvm_gmem_migrate_folio(struct address_space *mapping,
