This will be used to remove the MMIO regions of the POWER9 XIVE
interrupt controller when the sPAPR machine is reseted.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 include/hw/sysbus.h |  1 +
 hw/core/sysbus.c    | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/include/hw/sysbus.h b/include/hw/sysbus.h
index 1aedcf05c92b..4c668fbbdc60 100644
--- a/include/hw/sysbus.h
+++ b/include/hw/sysbus.h
@@ -89,6 +89,7 @@ qemu_irq sysbus_get_connected_irq(SysBusDevice *dev, int n);
 void sysbus_mmio_map(SysBusDevice *dev, int n, hwaddr addr);
 void sysbus_mmio_map_overlap(SysBusDevice *dev, int n, hwaddr addr,
                              int priority);
+void sysbus_mmio_unmap(SysBusDevice *dev, int n);
 void sysbus_add_io(SysBusDevice *dev, hwaddr addr,
                    MemoryRegion *mem);
 MemoryRegion *sysbus_address_space(SysBusDevice *dev);
diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
index 9f9edbcab96f..f90d87b058c3 100644
--- a/hw/core/sysbus.c
+++ b/hw/core/sysbus.c
@@ -153,6 +153,16 @@ static void sysbus_mmio_map_common(SysBusDevice *dev, int n, hwaddr addr,
     }
 }
 
+void sysbus_mmio_unmap(SysBusDevice *dev, int n)
+{
+    assert(n >= 0 && n < dev->num_mmio);
+
+    if (dev->mmio[n].addr != (hwaddr)-1) {
+        memory_region_del_subregion(get_system_memory(), dev->mmio[n].memory);
+        dev->mmio[n].addr = (hwaddr)-1;
+    }
+}
+
 void sysbus_mmio_map(SysBusDevice *dev, int n, hwaddr addr)
 {
     sysbus_mmio_map_common(dev, n, addr, false, 0);
-- 
2.20.1