mainline inclusion
commit 4802bf910eee98312c4a9777ac2567e6a0445c46
category: bugfix

The KVM_DIRTY_GFN_F_DIRTY flag ensures that the entry is valid. If
the read of the fields are not ordered after the read of the flag,
QEMU might see stale values.

Cc: Gavin Shan gshan@redhat.com
Reviewed-by: Philippe Mathieu-Daudé f4bug@amsat.org
Reviewed-by: Peter Xu peterx@redhat.com
Signed-off-by: Paolo Bonzini pbonzini@redhat.com