Qemu/Xen: Fix early freeing MSIX MMIO memory region

msix->mmio is added to XenPCIPassthroughState's object as property.
object_finalize_child_property is called for XenPCIPassthroughState's
object, which calls object_property_del_all, which is going to try to
delete msix->mmio. object_finalize_child_property() will access
msix->mmio's obj. But the whole msix struct has already been freed
by xen_pt_msix_delete. This will cause segment fault when msix->mmio
has been overwritten.

This patch is to fix the issue.

Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

1 files changed, 12 insertions, 1 deletions

diff --git a/hw/xen/xen_pt_msi.c b/hw/xen/xen_pt_msi.c
index e3d71945cd..82de2bced3 100644
--- a/hw/xen/xen_pt_msi.c
+++ b/hw/xen/xen_pt_msi.c
@@ -610,7 +610,7 @@ error_out:
     return rc;
 }
 
-void xen_pt_msix_delete(XenPCIPassthroughState *s)
+void xen_pt_msix_unmap(XenPCIPassthroughState *s)
 {
     XenPTMSIX *msix = s->msix;
 
@@ -627,6 +627,17 @@ void xen_pt_msix_delete(XenPCIPassthroughState *s)
     }
 
     memory_region_del_subregion(&s->bar[msix->bar_index], &msix->mmio);
+}
+
+void xen_pt_msix_delete(XenPCIPassthroughState *s)
+{
+    XenPTMSIX *msix = s->msix;
+
+    if (!msix) {
+        return;
+    }
+
+    object_unparent(OBJECT(&msix->mmio));
 
     g_free(s->msix);
     s->msix = NULL;