[Qemu-devel] [PULL 1/1] pci: Only unmap bus_master_enabled_region if was added previously

["Michael S. Tsirkin" <mst@redhat.com>]

From: Alexey Kardashevskiy <aik@ozlabs.ru>

Normally pci_init_bus_master() would be called either via
bus->machine_done.notify or directly from do_pci_register_device().

However if a device's realize() failed, pci_init_bus_master() is not
called, and do_pci_unregister_device() fails on
memory_region_del_subregion() as it was not mapped.

This adds a check that subregion was mapped before unmapping it.

Fixes: c53598ed18e4 ("pci: Add missing drop of bus master AS reference")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: John Snow <jsnow@redhat.com>
---
 hw/pci/pci.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index bd8043c..259483b 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -869,8 +869,10 @@ static void do_pci_unregister_device(PCIDevice *pci_dev)
     pci_dev->bus->devices[pci_dev->devfn] = NULL;
     pci_config_free(pci_dev);
 
-    memory_region_del_subregion(&pci_dev->bus_master_container_region,
-                                &pci_dev->bus_master_enable_region);
+    if (memory_region_is_mapped(&pci_dev->bus_master_enable_region)) {
+        memory_region_del_subregion(&pci_dev->bus_master_container_region,
+                                    &pci_dev->bus_master_enable_region);
+    }
     address_space_destroy(&pci_dev->bus_master_as);
 }
 
-- 
MST