[Qemu-devel] [PATCH 03/39] pci: split exit and finalize

[Paolo Bonzini]

To properly support devices that do DMA out of the BQL, destruction
needs to be done in two phases.  First, the device is unrealized;
at this point, pending memory accesses can still be completed, but
no new accesses will be started.  The second part is freeing the
device, which happens only after the reference count drops to zero;
this means that all memory accesses are complete.

This patch changes the PCI core to delay destruction of the
bus-master address space and root region.

Signed-off-by: Paolo Bonzini <address@hidden>
---
 hw/pci/pci.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 776ad96..b60d9d0d 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -779,6 +779,16 @@ static void pci_config_free(PCIDevice *pci_dev)
     g_free(pci_dev->used);
 }
 
+static void pci_device_instance_finalize(Object *obj)
+{
+    PCIDevice *pci_dev = PCI_DEVICE(obj);
+
+    qemu_free_irqs(pci_dev->irq);
+
+    address_space_destroy(&pci_dev->bus_master_as);
+    memory_region_destroy(&pci_dev->bus_master_enable_region);
+}
+
 /* -1 for devfn means auto assign */
 static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
                                          const char *name, int devfn)
@@ -866,12 +876,8 @@ static PCIDevice *do_pci_register_device(PCIDevice 
*pci_dev, PCIBus *bus,
 
 static void do_pci_unregister_device(PCIDevice *pci_dev)
 {
-    qemu_free_irqs(pci_dev->irq);
     pci_dev->bus->devices[pci_dev->devfn] = NULL;
     pci_config_free(pci_dev);
-
-    address_space_destroy(&pci_dev->bus_master_as);
-    memory_region_destroy(&pci_dev->bus_master_enable_region);
 }
 
 static void pci_unregister_io_regions(PCIDevice *pci_dev)
@@ -2243,6 +2249,7 @@ static const TypeInfo pci_device_type_info = {
     .abstract = true,
     .class_size = sizeof(PCIDeviceClass),
     .class_init = pci_device_class_init,
+    .instance_finalize = pci_device_instance_finalize,
 };
 
 static void pci_register_types(void)
-- 
1.8.1.4