To support guest_memfd memory preservation with LUO, guest_memfd luo code needs to access guest_memfd internals and reconstruct guest_memfd file instances from a preserved state.
Extract gmem_file, gmem_inode, and the GMEM_I() helper from guest_memfd.c into a new internal header virt/kvm/guest_memfd.h. Additionally, split __kvm_gmem_create() to expose a non-static __kvm_gmem_create_file() helper. This helper returns a struct file instead of a file descriptor, enabling file creation and initialization without installing it into a file descriptor table. Signed-off-by: Tarun Sahu <[email protected]> --- virt/kvm/guest_memfd.c | 68 +++++++++++++++++------------------------- virt/kvm/guest_memfd.h | 39 ++++++++++++++++++++++++ 2 files changed, 67 insertions(+), 40 deletions(-) create mode 100644 virt/kvm/guest_memfd.h diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 69c9d6d546b2..6740ae2bf948 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -7,38 +7,12 @@ #include <linux/mempolicy.h> #include <linux/pseudo_fs.h> #include <linux/pagemap.h> +#include "guest_memfd.h" #include "kvm_mm.h" static struct vfsmount *kvm_gmem_mnt; -/* - * A guest_memfd instance can be associated multiple VMs, each with its own - * "view" of the underlying physical memory. - * - * The gmem's inode is effectively the raw underlying physical storage, and is - * used to track properties of the physical memory, while each gmem file is - * effectively a single VM's view of that storage, and is used to track assets - * specific to its associated VM, e.g. memslots=>gmem bindings. - */ -struct gmem_file { - struct kvm *kvm; - struct xarray bindings; - struct list_head entry; -}; - -struct gmem_inode { - struct shared_policy policy; - struct inode vfs_inode; - struct list_head gmem_file_list; - - u64 flags; -}; - -static __always_inline struct gmem_inode *GMEM_I(struct inode *inode) -{ - return container_of(inode, struct gmem_inode, vfs_inode); -} #define kvm_gmem_for_each_file(f, inode) \ list_for_each_entry(f, &GMEM_I(inode)->gmem_file_list, entry) @@ -556,23 +530,17 @@ bool __weak kvm_arch_supports_gmem_init_shared(struct kvm *kvm) return true; } -static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) +struct file *__kvm_gmem_create_file(struct kvm *kvm, loff_t size, u64 flags) { static const char *name = "[kvm-gmem]"; struct gmem_file *f; struct inode *inode; struct file *file; - int fd, err; - - fd = get_unused_fd_flags(0); - if (fd < 0) - return fd; + int err; f = kzalloc_obj(*f); - if (!f) { - err = -ENOMEM; - goto err_fd; - } + if (!f) + return ERR_PTR(-ENOMEM); /* __fput() will take care of fops_put(). */ if (!fops_get(&kvm_gmem_fops)) { @@ -611,8 +579,7 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) xa_init(&f->bindings); list_add(&f->entry, &GMEM_I(inode)->gmem_file_list); - fd_install(fd, file); - return fd; + return file; err_inode: iput(inode); @@ -620,7 +587,28 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) fops_put(&kvm_gmem_fops); err_gmem: kfree(f); -err_fd: + return ERR_PTR(err); +} + +static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) +{ + struct file *file; + int fd, err; + + fd = get_unused_fd_flags(0); + if (fd < 0) + return fd; + + file = __kvm_gmem_create_file(kvm, size, flags); + if (IS_ERR(file)) { + err = PTR_ERR(file); + goto err_put_fd; + } + + fd_install(fd, file); + return fd; + +err_put_fd: put_unused_fd(fd); return err; } diff --git a/virt/kvm/guest_memfd.h b/virt/kvm/guest_memfd.h new file mode 100644 index 000000000000..c528b046dd69 --- /dev/null +++ b/virt/kvm/guest_memfd.h @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __KVM_GUEST_MEMFD_H__ +#define __KVM_GUEST_MEMFD_H__ 1 + +#include <linux/kvm_host.h> +#include <linux/fs.h> +#include <linux/mempolicy.h> + +/* + * A guest_memfd instance can be associated multiple VMs, each with its own + * "view" of the underlying physical memory. + * + * The gmem's inode is effectively the raw underlying physical storage, and is + * used to track properties of the physical memory, while each gmem file is + * effectively a single VM's view of that storage, and is used to track assets + * specific to its associated VM, e.g. memslots=>gmem bindings. + */ +struct gmem_file { + struct kvm *kvm; + struct xarray bindings; + struct list_head entry; +}; + +struct gmem_inode { + struct shared_policy policy; + struct inode vfs_inode; + struct list_head gmem_file_list; + + u64 flags; +}; + +static inline struct gmem_inode *GMEM_I(struct inode *inode) +{ + return container_of(inode, struct gmem_inode, vfs_inode); +} + +struct file *__kvm_gmem_create_file(struct kvm *kvm, loff_t size, u64 flags); + +#endif /* __KVM_GUEST_MEMFD_H__ */ -- 2.54.0.563.g4f69b47b94-goog
