From 2894a0e214cd340187c1692eb3f8aba1f964f7d0 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@redhat.com>
Date: Mon, 21 Jun 2010 10:57:45 +0300
Subject: [PATCH] --- yaml --- r: 202365 b: refs/heads/master c:
 7ac77099ce88a0c31b75acd0ec5ef3da4415a6d8 h: refs/heads/master i:   202363:
 3a6641475933344291ea071a9adbcda358e7ddee v: v3

---
 [refs]                   | 2 +-
 trunk/arch/x86/kvm/x86.c | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 7ba0c490efc5..6efc0fc9a148 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e36d96f7cfaa71870c407131eb4fbd38ea285c01
+refs/heads/master: 7ac77099ce88a0c31b75acd0ec5ef3da4415a6d8
diff --git a/trunk/arch/x86/kvm/x86.c b/trunk/arch/x86/kvm/x86.c
index 7ef44107a14a..68be38e233f5 100644
--- a/trunk/arch/x86/kvm/x86.c
+++ b/trunk/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);