[RFC PATCH 1/5] KVM: guest_memfd: add kvm_gmem_vma_is_gmem

[Nikita Kalyazin]

It will be used to distinguish the vma type in userfaultfd code.
This likely needs to be done in the guestmem library.

Signed-off-by: Nikita Kalyazin <kalyazin@xxxxxxxxxx>
---
 virt/kvm/guest_memfd.c | 5 +++++
 virt/kvm/kvm_mm.h      | 1 +
 2 files changed, 6 insertions(+)

diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index f93fe5835173..af825f7494ea 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -500,6 +500,11 @@ static ssize_t kvm_kmem_gmem_write(struct file *file, const char __user *buf,
 	return ret && start == (*offset >> PAGE_SHIFT) ?
 		ret : *offset - (start << PAGE_SHIFT);
 }
+
+bool kvm_gmem_vma_is_gmem(struct vm_area_struct *vma)
+{
+	return vma->vm_ops == &kvm_gmem_vm_ops;
+}
 #endif /* CONFIG_KVM_GMEM_SHARED_MEM */
 
 static struct file_operations kvm_gmem_fops = {
diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h
index acef3f5c582a..09fcdf18a072 100644
--- a/virt/kvm/kvm_mm.h
+++ b/virt/kvm/kvm_mm.h
@@ -73,6 +73,7 @@ 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);
+bool kvm_gmem_vma_is_gmem(struct vm_area_struct *vma);
 #else
 static inline void kvm_gmem_init(struct module *module)
 {
-- 
2.47.1