pci: introduce a bus master container

96a8821d2141 ("virtio: unbreak virtio-pci with IOMMU after caching ring
translations") tries to make IOMMU works with virtio memory region
cache, but it requires IOMMU to be created before any virtio
devices. This is sub optimal, fixing this by introduce a bus master
container to make sure address space can be initialized during device
registering, and then we can safely set alias and make
bus_master_enable_region as its subregion during bus master
initialization.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 273f1e46025afdbec7430e6c015e62374f44f9ed..ad46390ec54d5e2d0a42a1cf24de70380d3043c1 100644 (file)
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -88,8 +88,8 @@ static void pci_init_bus_master(PCIDevice *pci_dev)
                              OBJECT(pci_dev), "bus master",
                              dma_as->root, 0, memory_region_size(dma_as->root));
     memory_region_set_enabled(&pci_dev->bus_master_enable_region, false);
-    address_space_init(&pci_dev->bus_master_as,
-                       &pci_dev->bus_master_enable_region, pci_dev->name);
+    memory_region_add_subregion(&pci_dev->bus_master_container_region, 0,
+                                &pci_dev->bus_master_enable_region);
 }
 
 static void pcibus_machine_done(Notifier *notifier, void *data)
@@ -995,6 +995,11 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
     pci_dev->devfn = devfn;
     pci_dev->requester_id_cache = pci_req_id_cache_get(pci_dev);
 
+    memory_region_init(&pci_dev->bus_master_container_region, OBJECT(pci_dev),
+                       "bus master container", UINT64_MAX);
+    address_space_init(&pci_dev->bus_master_as,
+                       &pci_dev->bus_master_container_region, pci_dev->name);
+
     if (qdev_hotplug) {
         pci_init_bus_master(pci_dev);
     }

diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 9349acbfb2786463b7ec676fc0fe6ab8cd471cb3..713ede00bf7f800022c97638d605c07c4690a2bd 100644 (file)
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -284,6 +284,7 @@ struct PCIDevice {
     char name[64];
     PCIIORegion io_regions[PCI_NUM_REGIONS];
     AddressSpace bus_master_as;
+    MemoryRegion bus_master_container_region;
     MemoryRegion bus_master_enable_region;
 
     /* do not access the following fields */