1 files changed, 6 insertions, 1 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7ef44107a14a..68be38e233f5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5491,6 +5491,11 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
                                 int user_alloc)
 {
         int npages = memslot->npages;
+        int map_flags = MAP_PRIVATE | MAP_ANONYMOUS;
+
+        /* Prevent internal slot pages from being moved by fork()/COW. */
+        if (memslot->id >= KVM_MEMORY_SLOTS)
+                map_flags = MAP_SHARED | MAP_ANONYMOUS;
 
         /*To keep backward compatibility with older userspace,
          *x86 needs to hanlde !user_alloc case.
@@ -5503,7 +5508,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
                         userspace_addr = do_mmap(NULL, 0,
                                                  npages * PAGE_SIZE,
                                                  PROT_READ | PROT_WRITE,
-                                                 MAP_PRIVATE | MAP_ANONYMOUS,
+                                                 map_flags,
                                                  0);
                         up_write(&current->mm->mmap_sem);