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KVM: guest_memfd: Rename "struct kvm_gmem" to "struct gmem_file"

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Rename the "kvm_gmem" structure to "gmem_file" in anticipation of using
dedicated guest_memfd inodes instead of anonyomous inodes, at which point
the "kvm_gmem" nomenclature becomes quite misleading.  In guest_memfd,
inodes are effectively the raw underlying physical storage, and will be
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.

Using "kvm_gmem" suggests that the per-VM/per-file structures are _the_
guest_memfd instance, which almost the exact opposite of reality.

Opportunistically rename local variables from "gmem" to "f", again to
avoid confusion once guest_memfd specific inodes come along.

No functional change intended.

Reviewed-by: Ackerley Tng <ackerleytng@google.com>
Tested-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Shivank Garg <shivankg@amd.com>
Tested-by: Shivank Garg <shivankg@amd.com>
Link: https://lore.kernel.org/r/20251016172853.52451-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson
2025-10-16 10:28:42 -07:00
parent 5f3e10797a
commit 497b1dfbca
1 changed files with 53 additions and 45 deletions
Download Patch File Download Diff File Expand all files Collapse all files

98
virt/kvm/guest_memfd.c
View File

@@ -7,7 +7,16 @@
#include "kvm_mm.h"
struct kvm_gmem {
/*
* 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;
@@ -115,16 +124,16 @@ static enum kvm_gfn_range_filter kvm_gmem_get_invalidate_filter(struct inode *in
return KVM_FILTER_PRIVATE;
}
static void __kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start,
static void __kvm_gmem_invalidate_begin(struct gmem_file *f, pgoff_t start,
pgoff_t end,
enum kvm_gfn_range_filter attr_filter)
{
bool flush = false, found_memslot = false;
struct kvm_memory_slot *slot;
struct kvm *kvm = gmem->kvm;
struct kvm *kvm = f->kvm;
unsigned long index;
xa_for_each_range(&gmem->bindings, index, slot, start, end - 1) {
xa_for_each_range(&f->bindings, index, slot, start, end - 1) {
pgoff_t pgoff = slot->gmem.pgoff;
struct kvm_gfn_range gfn_range = {
@@ -157,20 +166,20 @@ static void kvm_gmem_invalidate_begin(struct inode *inode, pgoff_t start,
{
struct list_head *gmem_list = &inode->i_mapping->i_private_list;
enum kvm_gfn_range_filter attr_filter;
struct kvm_gmem *gmem;
struct gmem_file *f;
attr_filter = kvm_gmem_get_invalidate_filter(inode);
list_for_each_entry(gmem, gmem_list, entry)
__kvm_gmem_invalidate_begin(gmem, start, end, attr_filter);
list_for_each_entry(f, gmem_list, entry)
__kvm_gmem_invalidate_begin(f, start, end, attr_filter);
}
static void __kvm_gmem_invalidate_end(struct kvm_gmem *gmem, pgoff_t start,
static void __kvm_gmem_invalidate_end(struct gmem_file *f, pgoff_t start,
pgoff_t end)
{
struct kvm *kvm = gmem->kvm;
struct kvm *kvm = f->kvm;
if (xa_find(&gmem->bindings, &start, end - 1, XA_PRESENT)) {
if (xa_find(&f->bindings, &start, end - 1, XA_PRESENT)) {
KVM_MMU_LOCK(kvm);
kvm_mmu_invalidate_end(kvm);
KVM_MMU_UNLOCK(kvm);
@@ -181,10 +190,10 @@ static void kvm_gmem_invalidate_end(struct inode *inode, pgoff_t start,
pgoff_t end)
{
struct list_head *gmem_list = &inode->i_mapping->i_private_list;
struct kvm_gmem *gmem;
struct gmem_file *f;
list_for_each_entry(gmem, gmem_list, entry)
__kvm_gmem_invalidate_end(gmem, start, end);
list_for_each_entry(f, gmem_list, entry)
__kvm_gmem_invalidate_end(f, start, end);
}
static long kvm_gmem_punch_hole(struct inode *inode, loff_t offset, loff_t len)
@@ -282,9 +291,9 @@ static long kvm_gmem_fallocate(struct file *file, int mode, loff_t offset,
static int kvm_gmem_release(struct inode *inode, struct file *file)
{
struct kvm_gmem *gmem = file->private_data;
struct gmem_file *f = file->private_data;
struct kvm_memory_slot *slot;
struct kvm *kvm = gmem->kvm;
struct kvm *kvm = f->kvm;
unsigned long index;
/*
@@ -304,7 +313,7 @@ static int kvm_gmem_release(struct inode *inode, struct file *file)
filemap_invalidate_lock(inode->i_mapping);
xa_for_each(&gmem->bindings, index, slot)
xa_for_each(&f->bindings, index, slot)
WRITE_ONCE(slot->gmem.file, NULL);
/*
@@ -312,18 +321,18 @@ 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_begin(f, 0, -1ul,
kvm_gmem_get_invalidate_filter(inode));
__kvm_gmem_invalidate_end(gmem, 0, -1ul);
__kvm_gmem_invalidate_end(f, 0, -1ul);
list_del(&gmem->entry);
list_del(&f->entry);
filemap_invalidate_unlock(inode->i_mapping);
mutex_unlock(&kvm->slots_lock);
xa_destroy(&gmem->bindings);
kfree(gmem);
xa_destroy(&f->bindings);
kfree(f);
kvm_put_kvm(kvm);
@@ -491,7 +500,7 @@ bool __weak kvm_arch_supports_gmem_init_shared(struct kvm *kvm)
static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags)
{
const char *anon_name = "[kvm-gmem]";
struct kvm_gmem *gmem;
struct gmem_file *f;
struct inode *inode;
struct file *file;
int fd, err;
@@ -500,14 +509,13 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags)
if (fd < 0)
return fd;
gmem = kzalloc(sizeof(*gmem), GFP_KERNEL);
if (!gmem) {
f = kzalloc(sizeof(*f), GFP_KERNEL);
if (!f) {
err = -ENOMEM;
goto err_fd;
}
file = anon_inode_create_getfile(anon_name, &kvm_gmem_fops, gmem,
O_RDWR, NULL);
file = anon_inode_create_getfile(anon_name, &kvm_gmem_fops, f, O_RDWR, NULL);
if (IS_ERR(file)) {
err = PTR_ERR(file);
goto err_gmem;
@@ -529,15 +537,15 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags)
WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping));
kvm_get_kvm(kvm);
gmem->kvm = kvm;
xa_init(&gmem->bindings);
list_add(&gmem->entry, &inode->i_mapping->i_private_list);
f->kvm = kvm;
xa_init(&f->bindings);
list_add(&f->entry, &inode->i_mapping->i_private_list);
fd_install(fd, file);
return fd;
err_gmem:
kfree(gmem);
kfree(f);
err_fd:
put_unused_fd(fd);
return err;
@@ -562,7 +570,7 @@ int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot,
{
loff_t size = slot->npages << PAGE_SHIFT;
unsigned long start, end;
struct kvm_gmem *gmem;
struct gmem_file *f;
struct inode *inode;
struct file *file;
int r = -EINVAL;
@@ -576,8 +584,8 @@ int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot,
if (file->f_op != &kvm_gmem_fops)
goto err;
gmem = file->private_data;
if (gmem->kvm != kvm)
f = file->private_data;
if (f->kvm != kvm)
goto err;
inode = file_inode(file);
@@ -591,8 +599,8 @@ int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot,
start = offset >> PAGE_SHIFT;
end = start + slot->npages;
if (!xa_empty(&gmem->bindings) &&
xa_find(&gmem->bindings, &start, end - 1, XA_PRESENT)) {
if (!xa_empty(&f->bindings) &&
xa_find(&f->bindings, &start, end - 1, XA_PRESENT)) {
filemap_invalidate_unlock(inode->i_mapping);
goto err;
}
@@ -607,7 +615,7 @@ int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot,
if (kvm_gmem_supports_mmap(inode))
slot->flags |= KVM_MEMSLOT_GMEM_ONLY;
xa_store_range(&gmem->bindings, start, end - 1, slot, GFP_KERNEL);
xa_store_range(&f->bindings, start, end - 1, slot, GFP_KERNEL);
filemap_invalidate_unlock(inode->i_mapping);
/*
@@ -625,7 +633,7 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot)
{
unsigned long start = slot->gmem.pgoff;
unsigned long end = start + slot->npages;
struct kvm_gmem *gmem;
struct gmem_file *f;
struct file *file;
/*
@@ -636,10 +644,10 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot)
if (!file)
return;
gmem = file->private_data;
f = file->private_data;
filemap_invalidate_lock(file->f_mapping);
xa_store_range(&gmem->bindings, start, end - 1, NULL, GFP_KERNEL);
xa_store_range(&f->bindings, start, end - 1, NULL, GFP_KERNEL);
/*
* synchronize_srcu(&kvm->srcu) ensured that kvm_gmem_get_pfn()
@@ -657,17 +665,17 @@ static struct folio *__kvm_gmem_get_pfn(struct file *file,
pgoff_t index, kvm_pfn_t *pfn,
bool *is_prepared, int *max_order)
{
struct file *gmem_file = READ_ONCE(slot->gmem.file);
struct kvm_gmem *gmem = file->private_data;
struct file *slot_file = READ_ONCE(slot->gmem.file);
struct gmem_file *f = file->private_data;
struct folio *folio;
if (file != gmem_file) {
WARN_ON_ONCE(gmem_file);
if (file != slot_file) {
WARN_ON_ONCE(slot_file);
return ERR_PTR(-EFAULT);
}
if (xa_load(&gmem->bindings, index) != slot) {
WARN_ON_ONCE(xa_load(&gmem->bindings, index));
if (xa_load(&f->bindings, index) != slot) {
WARN_ON_ONCE(xa_load(&f->bindings, index));
return ERR_PTR(-EIO);
}