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Date: Tue, 26 Sep 2023 11:03:46 -0700
From: isaku.yamahata@...el.com
To: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: isaku.yamahata@...el.com, isaku.yamahata@...il.com,
Michael Roth <michael.roth@....com>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
linux-coco@...ts.linux.dev, Chao Peng <chao.p.peng@...ux.intel.com>
Subject: [PATCH] KVM: guest_memfd: Refactor kvm_gmem into inode->i_private
From: Isaku Yamahata <isaku.yamahata@...el.com>
Refactor guest_memfd to use inode->i_private to store info about kvm_gmem.
Currently it is stored in the following way.
- flags in inode->i_private
- struct kvm_gmem in file->private_data
- struct kvm_gmem in linked linst in inode->i_mapping->private_list
And this list has single entry.
The relationship between struct file, struct inode and struct kvm_gmem is
1:1, not 1:many. Consolidate related info in one place.
- Move flags into struct kvm_gmem
- Store struct kvm_gmem in inode->i_private
- Don't use file->private_data
- Don't use inode->i_mapping_private_list
- Introduce a helper conversion function from inode to kvm_gmem
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
virt/kvm/guest_memfd.c | 53 ++++++++++++++++++------------------------
1 file changed, 23 insertions(+), 30 deletions(-)
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 4f3a313f5532..66dd9b55e85c 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -14,14 +14,19 @@ static struct vfsmount *kvm_gmem_mnt;
struct kvm_gmem {
struct kvm *kvm;
struct xarray bindings;
- struct list_head entry;
+ unsigned long flags;
};
+static struct kvm_gmem *to_gmem(struct inode *inode)
+{
+ return inode->i_private;
+}
+
static struct folio *kvm_gmem_get_huge_folio(struct inode *inode, pgoff_t index)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
unsigned long huge_index = round_down(index, HPAGE_PMD_NR);
- unsigned long flags = (unsigned long)inode->i_private;
+ unsigned long flags = to_gmem(inode)->flags;
struct address_space *mapping = inode->i_mapping;
gfp_t gfp = mapping_gfp_mask(mapping);
struct folio *folio;
@@ -134,26 +139,22 @@ 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->private_list;
+ struct address_space *mapping = inode->i_mapping;
+ struct kvm_gmem *gmem = to_gmem(inode);
pgoff_t start = offset >> PAGE_SHIFT;
pgoff_t end = (offset + len) >> PAGE_SHIFT;
- struct kvm_gmem *gmem;
/*
* Bindings must 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);
+ filemap_invalidate_lock(mapping);
+ 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);
+ kvm_gmem_invalidate_end(gmem, start, end);
+ filemap_invalidate_unlock(mapping);
return 0;
}
@@ -231,7 +232,7 @@ 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 kvm_gmem *gmem = to_gmem(inode);
struct kvm_memory_slot *slot;
struct kvm *kvm = gmem->kvm;
unsigned long index;
@@ -260,8 +261,6 @@ static int kvm_gmem_release(struct inode *inode, struct file *file)
kvm_gmem_invalidate_begin(gmem, 0, -1ul);
kvm_gmem_invalidate_end(gmem, 0, -1ul);
- list_del(&gmem->entry);
-
filemap_invalidate_unlock(inode->i_mapping);
mutex_unlock(&kvm->slots_lock);
@@ -305,8 +304,7 @@ static int kvm_gmem_migrate_folio(struct address_space *mapping,
static int kvm_gmem_error_page(struct address_space *mapping, struct page *page)
{
- struct list_head *gmem_list = &mapping->private_list;
- struct kvm_gmem *gmem;
+ struct kvm_gmem *gmem = to_gmem(mapping->host);
pgoff_t start, end;
filemap_invalidate_lock_shared(mapping);
@@ -314,8 +312,7 @@ static int kvm_gmem_error_page(struct address_space *mapping, struct page *page)
start = page->index;
end = start + thp_nr_pages(page);
- list_for_each_entry(gmem, gmem_list, entry)
- kvm_gmem_invalidate_begin(gmem, start, end);
+ kvm_gmem_invalidate_begin(gmem, start, end);
/*
* Do not truncate the range, what action is taken in response to the
@@ -326,8 +323,7 @@ static int kvm_gmem_error_page(struct address_space *mapping, struct page *page)
* error to userspace.
*/
- list_for_each_entry(gmem, gmem_list, entry)
- kvm_gmem_invalidate_end(gmem, start, end);
+ kvm_gmem_invalidate_end(gmem, start, end);
filemap_invalidate_unlock_shared(mapping);
@@ -382,7 +378,6 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags,
if (err)
goto err_inode;
- 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;
@@ -417,10 +412,9 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags,
kvm_get_kvm(kvm);
gmem->kvm = kvm;
xa_init(&gmem->bindings);
+ gmem->flags = flags;
- file->private_data = gmem;
-
- list_add(&gmem->entry, &inode->i_mapping->private_list);
+ inode->i_private = gmem;
fd_install(fd, file);
return fd;
@@ -476,12 +470,11 @@ 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;
+ inode = file_inode(file);
+ gmem = to_gmem(inode);
if (gmem->kvm != kvm)
goto err;
- inode = file_inode(file);
-
if (offset < 0 || !PAGE_ALIGNED(offset))
return -EINVAL;
@@ -538,7 +531,7 @@ void kvm_gmem_unbind(struct kvm_memory_slot *slot)
if (!file)
return;
- gmem = file->private_data;
+ gmem = to_gmem(file_inode(file));
filemap_invalidate_lock(file->f_mapping);
xa_store_range(&gmem->bindings, start, end - 1, NULL, GFP_KERNEL);
@@ -563,7 +556,7 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
if (!file)
return -EFAULT;
- gmem = file->private_data;
+ gmem = to_gmem(file_inode(file));
if (WARN_ON_ONCE(xa_load(&gmem->bindings, index) != slot)) {
r = -EIO;
--
2.25.1
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