3 files changed, 23 insertions, 0 deletions
diff --git a/exec.c b/exec.c
index 2effd04f62..c64938124b 100644
--- a/exec.c
+++ b/exec.c
@@ -2484,6 +2484,9 @@ ram_addr_t qemu_ram_alloc(ram_addr_t size)
 
     last_ram_offset += size;
 
+    if (kvm_enabled())
+        kvm_setup_guest_memory(new_block->host, size);
+
     return new_block->offset;
 }
 
diff --git a/kvm-all.c b/kvm-all.c
index 0da5c7aa8d..36659a95e8 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -773,6 +773,24 @@ int kvm_has_sync_mmu(void)
     return 0;
 }
 
+void kvm_setup_guest_memory(void *start, size_t size)
+{
+    if (!kvm_has_sync_mmu()) {
+#ifdef MADV_DONTFORK
+        int ret = madvise(start, size, MADV_DONTFORK);
+
+        if (ret) {
+            perror("madvice");
+            exit(1);
+        }
+#else
+        fprintf(stderr,
+                "Need MADV_DONTFORK in absence of synchronous KVM MMU\n");
+        exit(1);
+#endif
+    }
+}
+
 #ifdef KVM_CAP_SET_GUEST_DEBUG
 struct kvm_sw_breakpoint *kvm_find_sw_breakpoint(CPUState *env,
                                                  target_ulong pc)
diff --git a/kvm.h b/kvm.h
index 803a874113..0ea24266be 100644
--- a/kvm.h
+++ b/kvm.h
@@ -48,6 +48,8 @@ int kvm_log_stop(target_phys_addr_t phys_addr, ram_addr_t size);
 
 int kvm_has_sync_mmu(void);
 
+void kvm_setup_guest_memory(void *start, size_t size);
+
 int kvm_coalesce_mmio_region(target_phys_addr_t start, ram_addr_t size);
 int kvm_uncoalesce_mmio_region(target_phys_addr_t start, ram_addr_t size);