---
  include/linux/kvm_host.h |  2 ++
  virt/kvm/guest_memfd.c   | 31 +++++++++++++++++++++++++++++++
  2 files changed, 33 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 3915da2a61778..27687fb9d5201 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h

@@ -2575,6 +2575,8 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
  #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
  
  #ifdef CONFIG_KVM_GUEST_MEMFD
+bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn);
+
  int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
  		     gfn_t gfn, kvm_pfn_t *pfn, struct page **page,
  		     int *max_order);

diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 8101f64e0366f..bca912db5be6e 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c

@@ -510,6 +510,37 @@ static int kvm_gmem_mmap(struct file *file, struct vm_area_struct *vma)
  	return 0;
  }
  
+bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn)
+{
+	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+	struct inode *inode;
+
+	/*
+	 * If this gfn has no associated memslot, there's no chance of the gfn
+	 * being backed by private memory, since guest_memfd must be used for
+	 * private memory, and guest_memfd must be associated with some memslot.
+	 */
+	if (!slot)
+		return 0;
+
+	CLASS(gmem_get_file, file)(slot);
+	if (!file)
+		return 0;
+
+	inode = file_inode(file);
+
+	/*
+	 * Rely on the maple tree's internal RCU lock to ensure a
+	 * stable result. This result can become stale as soon as the
+	 * lock is dropped, so the caller _must_ still protect
+	 * consumption of private vs. shared by checking
+	 * mmu_invalidate_retry_gfn() under mmu_lock to serialize
+	 * against ongoing attribute updates.
+	 */
+	return kvm_gmem_is_private_mem(inode, kvm_gmem_get_index(slot, gfn));
+}
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_is_private);
+
  static struct file_operations kvm_gmem_fops = {
  	.mmap		= kvm_gmem_mmap,
  	.open		= generic_file_open,