From 86f5029a284c38480bc7b2627aa4beb262c20074 Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Tue, 13 Jan 2009 18:36:17 -0200
Subject: [PATCH 66/70] kvm: qemu: make --mem-path memory allocation depend on mmu notifiers

Without mmu notifiers usage of hugepages to back guest memory can cause
memory corruption.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
RH-Upstream-status: applied(kvm/master)
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
---
 qemu/vl.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/qemu/vl.c b/qemu/vl.c
index 187d39e..3276698 100644
--- a/qemu/vl.c
+++ b/qemu/vl.c
@@ -4801,6 +4801,11 @@ void *alloc_mem_area(size_t memory, unsigned long *len, const char *path)
     int flags;
 #endif
 
+    if (!kvm_has_sync_mmu()) {
+        fprintf(stderr, "host lacks mmu notifiers, disabling --mem-path\n");
+        return NULL;
+    }
+
     if (asprintf(&filename, "%s/kvm.XXXXXX", path) == -1)
 	return NULL;
 
-- 
1.6.1