Use the recently created mm/guest_memfd implementation. No functional
change intended.
Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
---
virt/kvm/Kconfig | 1 +
virt/kvm/guest_memfd.c | 299 ++++++++-----------------------------------------
virt/kvm/kvm_main.c | 2 -
virt/kvm/kvm_mm.h | 6 -
4 files changed, 49 insertions(+), 259 deletions(-)
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index b14e14cdbfb9..1147e004fcbd 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -106,6 +106,7 @@ config KVM_GENERIC_MEMORY_ATTRIBUTES
config KVM_PRIVATE_MEM
select XARRAY_MULTI
+ select GUEST_MEMFD
bool
config KVM_GENERIC_PRIVATE_MEM
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 1c509c351261..2fe3ff9e5793 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -1,9 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
-#include <linux/backing-dev.h>
-#include <linux/falloc.h>
+#include <linux/guest_memfd.h>
#include <linux/kvm_host.h>
#include <linux/pagemap.h>
-#include <linux/anon_inodes.h>
#include "kvm_mm.h"
@@ -13,9 +11,16 @@ struct kvm_gmem {
struct list_head entry;
};
-static int kvm_gmem_prepare_folio(struct inode *inode, pgoff_t index, struct folio *folio)
+static inline struct kvm_gmem *inode_to_kvm_gmem(struct inode *inode)
{
+ struct list_head *gmem_list = &inode->i_mapping->i_private_list;
+
+ return list_first_entry_or_null(gmem_list, struct kvm_gmem, entry);
+}
+
#ifdef CONFIG_HAVE_KVM_GMEM_PREPARE
+static int kvm_gmem_prepare_folio(struct inode *inode, pgoff_t index, struct folio *folio)
+{
struct list_head *gmem_list = &inode->i_mapping->i_private_list;
struct kvm_gmem *gmem;
@@ -45,57 +50,14 @@ static int kvm_gmem_prepare_folio(struct inode *inode, pgoff_t index, struct fol
}
}
-#endif
return 0;
}
+#endif
-static struct folio *kvm_gmem_get_folio(struct inode *inode, pgoff_t index, bool prepare)
-{
- struct folio *folio;
-
- /* TODO: Support huge pages. */
- folio = filemap_grab_folio(inode->i_mapping, index);
- if (IS_ERR(folio))
- return folio;
-
- /*
- * 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);
- }
-
- if (prepare) {
- int r = kvm_gmem_prepare_folio(inode, index, folio);
- if (r < 0) {
- folio_unlock(folio);
- folio_put(folio);
- return ERR_PTR(r);
- }
- }
-
- /*
- * Ignore accessed, referenced, and dirty flags. The memory is
- * unevictable and there is no storage to write back to.
- */
- return folio;
-}
-
-static void kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start,
+static int kvm_gmem_invalidate_begin(struct inode *inode, pgoff_t start,
pgoff_t end)
{
+ struct kvm_gmem *gmem = inode_to_kvm_gmem(inode);
bool flush = false, found_memslot = false;
struct kvm_memory_slot *slot;
struct kvm *kvm = gmem->kvm;
@@ -126,11 +88,14 @@ static void kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start,
if (found_memslot)
KVM_MMU_UNLOCK(kvm);
+
+ return 0;
}
-static void kvm_gmem_invalidate_end(struct kvm_gmem *gmem, pgoff_t start,
+static void kvm_gmem_invalidate_end(struct inode *inode, pgoff_t start,
pgoff_t end)
{
+ struct kvm_gmem *gmem = inode_to_kvm_gmem(inode);
struct kvm *kvm = gmem->kvm;
if (xa_find(&gmem->bindings, &start, end - 1, XA_PRESENT)) {
@@ -140,106 +105,9 @@ static void kvm_gmem_invalidate_end(struct kvm_gmem *gmem, pgoff_t start,
}
}
-static long kvm_gmem_punch_hole(struct inode *inode, loff_t offset, loff_t len)
-{
- struct list_head *gmem_list = &inode->i_mapping->i_private_list;
- pgoff_t start = offset >> PAGE_SHIFT;
- pgoff_t end = (offset + len) >> PAGE_SHIFT;
- struct kvm_gmem *gmem;
-
- /*
- * Bindings must be stable across invalidation to ensure the start+end
- * are balanced.
- */
- filemap_invalidate_lock(inode->i_mapping);
-
- list_for_each_entry(gmem, gmem_list, entry)
- kvm_gmem_invalidate_begin(gmem, start, end);
-
- truncate_inode_pages_range(inode->i_mapping, offset, offset + len - 1);
-
- list_for_each_entry(gmem, gmem_list, entry)
- kvm_gmem_invalidate_end(gmem, start, end);
-
- filemap_invalidate_unlock(inode->i_mapping);
-
- return 0;
-}
-
-static long kvm_gmem_allocate(struct inode *inode, loff_t offset, loff_t len)
+static int kvm_gmem_release(struct inode *inode)
{
- struct address_space *mapping = inode->i_mapping;
- pgoff_t start, index, end;
- int r;
-
- /* Dedicated guest is immutable by default. */
- if (offset + len > i_size_read(inode))
- return -EINVAL;
-
- filemap_invalidate_lock_shared(mapping);
-
- start = offset >> PAGE_SHIFT;
- end = (offset + len) >> PAGE_SHIFT;
-
- r = 0;
- for (index = start; index < end; ) {
- struct folio *folio;
-
- if (signal_pending(current)) {
- r = -EINTR;
- break;
- }
-
- folio = kvm_gmem_get_folio(inode, index, true);
- if (IS_ERR(folio)) {
- r = PTR_ERR(folio);
- break;
- }
-
- index = folio_next_index(folio);
-
- folio_unlock(folio);
- folio_put(folio);
-
- /* 64-bit only, wrapping the index should be impossible. */
- if (WARN_ON_ONCE(!index))
- break;
-
- cond_resched();
- }
-
- filemap_invalidate_unlock_shared(mapping);
-
- return r;
-}
-
-static long kvm_gmem_fallocate(struct file *file, int mode, loff_t offset,
- loff_t len)
-{
- int ret;
-
- if (!(mode & FALLOC_FL_KEEP_SIZE))
- return -EOPNOTSUPP;
-
- if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
- return -EOPNOTSUPP;
-
- if (!PAGE_ALIGNED(offset) || !PAGE_ALIGNED(len))
- return -EINVAL;
-
- if (mode & FALLOC_FL_PUNCH_HOLE)
- ret = kvm_gmem_punch_hole(file_inode(file), offset, len);
- else
- ret = kvm_gmem_allocate(file_inode(file), offset, len);
-
- if (!ret)
- file_modified(file);
- return ret;
-}
-
-static int kvm_gmem_release(struct inode *inode, struct file *file)
-{
- struct kvm_gmem *gmem = file->private_data;
+ struct kvm_gmem *gmem = inode_to_kvm_gmem(inode);
struct kvm_memory_slot *slot;
struct kvm *kvm = gmem->kvm;
unsigned long index;
@@ -265,8 +133,8 @@ static int kvm_gmem_release(struct inode *inode, struct file *file)
* Zap all SPTEs pointed at by this file. Do not free the backing
* memory, as its lifetime is associated with the inode, not the file.
*/
- kvm_gmem_invalidate_begin(gmem, 0, -1ul);
- kvm_gmem_invalidate_end(gmem, 0, -1ul);
+ kvm_gmem_invalidate_begin(inode, 0, -1ul);
+ kvm_gmem_invalidate_end(inode, 0, -1ul);
list_del(&gmem->entry);
@@ -293,56 +161,6 @@ static inline struct file *kvm_gmem_get_file(struct kvm_memory_slot *slot)
return get_file_active(&slot->gmem.file);
}
-static struct file_operations kvm_gmem_fops = {
- .open = generic_file_open,
- .release = kvm_gmem_release,
- .fallocate = kvm_gmem_fallocate,
-};
-
-void kvm_gmem_init(struct module *module)
-{
- kvm_gmem_fops.owner = module;
-}
-
-static int kvm_gmem_migrate_folio(struct address_space *mapping,
- struct folio *dst, struct folio *src,
- enum migrate_mode mode)
-{
- WARN_ON_ONCE(1);
- return -EINVAL;
-}
-
-static int kvm_gmem_error_folio(struct address_space *mapping, struct folio *folio)
-{
- struct list_head *gmem_list = &mapping->i_private_list;
- struct kvm_gmem *gmem;
- pgoff_t start, end;
-
- filemap_invalidate_lock_shared(mapping);
-
- start = folio->index;
- end = start + folio_nr_pages(folio);
-
- list_for_each_entry(gmem, gmem_list, entry)
- kvm_gmem_invalidate_begin(gmem, start, end);
-
- /*
- * Do not truncate the range, what action is taken in response to the
- * error is userspace's decision (assuming the architecture supports
- * gracefully handling memory errors). If/when the guest attempts to
- * access a poisoned page, kvm_gmem_get_pfn() will return -EHWPOISON,
- * at which point KVM can either terminate the VM or propagate the
- * error to userspace.
- */
-
- list_for_each_entry(gmem, gmem_list, entry)
- kvm_gmem_invalidate_end(gmem, start, end);
-
- filemap_invalidate_unlock_shared(mapping);
-
- return MF_DELAYED;
-}
-
#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
static void kvm_gmem_free_folio(struct folio *folio)
{
@@ -354,34 +172,25 @@ static void kvm_gmem_free_folio(struct folio *folio)
}
#endif
-static const struct address_space_operations kvm_gmem_aops = {
- .dirty_folio = noop_dirty_folio,
- .migrate_folio = kvm_gmem_migrate_folio,
- .error_remove_folio = kvm_gmem_error_folio,
+static const struct guest_memfd_operations kvm_gmem_ops = {
+ .invalidate_begin = kvm_gmem_invalidate_begin,
+ .invalidate_end = kvm_gmem_invalidate_end,
+#ifdef CONFIG_HAVE_KVM_GMEM_PREAPRE
+ .prepare = kvm_gmem_prepare_folio,
+#endif
#ifdef CONFIG_HAVE_KVM_GMEM_INVALIDATE
.free_folio = kvm_gmem_free_folio,
#endif
+ .release = kvm_gmem_release,
};
-static int kvm_gmem_getattr(struct mnt_idmap *idmap, const struct path *path,
- struct kstat *stat, u32 request_mask,
- unsigned int query_flags)
+static inline struct kvm_gmem *file_to_kvm_gmem(struct file *file)
{
- struct inode *inode = path->dentry->d_inode;
-
- generic_fillattr(idmap, request_mask, inode, stat);
- return 0;
-}
+ if (!is_guest_memfd(file, &kvm_gmem_ops))
+ return NULL;
-static int kvm_gmem_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
- struct iattr *attr)
-{
- return -EINVAL;
+ return inode_to_kvm_gmem(file_inode(file));
}
-static const struct inode_operations kvm_gmem_iops = {
- .getattr = kvm_gmem_getattr,
- .setattr = kvm_gmem_setattr,
-};
static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags)
{
@@ -401,31 +210,16 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags)
goto err_fd;
}
- file = anon_inode_create_getfile(anon_name, &kvm_gmem_fops, gmem,
- O_RDWR, NULL);
+ file = guest_memfd_alloc(anon_name, &kvm_gmem_ops, size, 0);
if (IS_ERR(file)) {
err = PTR_ERR(file);
goto err_gmem;
}
- file->f_flags |= O_LARGEFILE;
-
- inode = file->f_inode;
- WARN_ON(file->f_mapping != inode->i_mapping);
-
- inode->i_private = (void *)(unsigned long)flags;
- inode->i_op = &kvm_gmem_iops;
- inode->i_mapping->a_ops = &kvm_gmem_aops;
- inode->i_mode |= S_IFREG;
- inode->i_size = size;
- mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
- mapping_set_inaccessible(inode->i_mapping);
- /* Unmovable mappings are supposed to be marked unevictable as well. */
- WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping));
-
kvm_get_kvm(kvm);
gmem->kvm = kvm;
xa_init(&gmem->bindings);
+ inode = file_inode(file);
list_add(&gmem->entry, &inode->i_mapping->i_private_list);
fd_install(fd, file);
@@ -469,11 +263,8 @@ int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot,
if (!file)
return -EBADF;
- if (file->f_op != &kvm_gmem_fops)
- goto err;
-
- gmem = file->private_data;
- if (gmem->kvm != kvm)
+ gmem = file_to_kvm_gmem(file);
+ if (!gmem || gmem->kvm != kvm)
goto err;
inode = file_inode(file);
@@ -530,7 +321,9 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot)
if (!file)
return;
- gmem = file->private_data;
+ gmem = file_to_kvm_gmem(file);
+ if (!gmem)
+ return;
filemap_invalidate_lock(file->f_mapping);
xa_store_range(&gmem->bindings, start, end - 1, NULL, GFP_KERNEL);
@@ -548,20 +341,24 @@ static int __kvm_gmem_get_pfn(struct file *file, struct kvm_memory_slot *slot,
struct kvm_gmem *gmem = file->private_data;
struct folio *folio;
struct page *page;
- int r;
+ int r, flags = GUEST_MEMFD_GRAB_UPTODATE;
if (file != slot->gmem.file) {
WARN_ON_ONCE(slot->gmem.file);
return -EFAULT;
}
- gmem = file->private_data;
- if (xa_load(&gmem->bindings, index) != slot) {
- WARN_ON_ONCE(xa_load(&gmem->bindings, index));
+ gmem = file_to_kvm_gmem(file);
+ if (WARN_ON_ONCE(!gmem))
+ return -EINVAL;
+
+ if (WARN_ON_ONCE(xa_load(&gmem->bindings, index) != slot))
return -EIO;
- }
- folio = kvm_gmem_get_folio(file_inode(file), index, prepare);
+ if (prepare)
+ flags |= GUEST_MEMFD_PREPARE;
+
+ folio = guest_memfd_grab_folio(file, index, flags);
if (IS_ERR(folio))
return PTR_ERR(folio);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d0788d0a72cc..cad798f4e135 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -6516,8 +6516,6 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
if (WARN_ON_ONCE(r))
goto err_vfio;
- kvm_gmem_init(module);
-
/*
* Registration _must_ be the very last thing done, as this exposes
* /dev/kvm to userspace, i.e. all infrastructure must be setup!
diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h
index 715f19669d01..6336a4fdcf50 100644
--- a/virt/kvm/kvm_mm.h
+++ b/virt/kvm/kvm_mm.h
@@ -36,17 +36,11 @@ static inline void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm,
#endif /* HAVE_KVM_PFNCACHE */
#ifdef CONFIG_KVM_PRIVATE_MEM
-void kvm_gmem_init(struct module *module);
int kvm_gmem_create(struct kvm *kvm, struct kvm_create_guest_memfd *args);
int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot,
unsigned int fd, loff_t offset);
void kvm_gmem_unbind(struct kvm_memory_slot *slot);
#else
-static inline void kvm_gmem_init(struct module *module)
-{
-
-}
-
static inline int kvm_gmem_bind(struct kvm *kvm,
struct kvm_memory_slot *slot,
unsigned int fd, loff_t offset)
--
2.34.1
