commit 11c8aca938bff7f6b7fb9def732262f3ad9e91f9
Author: Jim Fehlig <jfehlig@suse.com>
Date:   Thu Jan 10 15:18:36 2019 -0700

    libxl: Set current memory value after successful balloon
    
    The libxl driver does not set the new memory value in the active domain def
    after a successful balloon. This results in the old memory value in
    <currentMemory>. E.g.
    
    virsh dumpxml test | grep currentMemory
      <currentMemory unit='KiB'>20971520</currentMemory>
    virsh setmem test 16777216 --live
    virsh dumpxml test | grep currentMemory
      <currentMemory unit='KiB'>20971520</currentMemory>
    
    Set the new memory value in active domain def after a successful call to
    libxl_set_memory_target().
    
    Signed-off-by: Jim Fehlig <jfehlig@suse.com>
    Reviewed-by: Ján Tomko <jtomko@redhat.com>

Index: libvirt-5.0.0/src/libxl/libxl_driver.c
===================================================================
--- libvirt-5.0.0.orig/src/libxl/libxl_driver.c
+++ libvirt-5.0.0/src/libxl/libxl_driver.c
@@ -1676,6 +1676,7 @@ libxlDomainSetMemoryFlags(virDomainPtr d
                                  " with libxenlight"), vm->def->id);
                 goto endjob;
             }
+            vm->def->mem.cur_balloon = newmem;
         }
 
         if (flags & VIR_DOMAIN_MEM_CONFIG) {