Re: [Qemu-devel] [RFC 2/7] pci: Change pci_bus_init() 'parent' parameter to PCIHostState

[Marcel Apfelbaum]

On 04/18/2017 02:48 PM, Eduardo Habkost wrote:

On Tue, Apr 18, 2017 at 01:51:02PM +1000, David Gibson wrote:

On Mon, Apr 17, 2017 at 06:59:11PM -0300, Eduardo Habkost wrote:

pci_bus_init() already requires 'parent' to be a PCI_HOST_BRIDGE object,
so change the parameter type to reflect that.

Cc: "Michael S. Tsirkin" <m...@redhat.com>
Cc: Marcel Apfelbaum <mar...@redhat.com>
Signed-off-by: Eduardo Habkost <ehabk...@redhat.com>

Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>

I had to do some looking to convince myself this wouldn't break P2P
bridges.

I wonder if we should rename pci_bus_init() / pci_bus_new() to make it
clearer that they're about creating a whole new PCI domain, and not
for a new bus within an existing domain.

Good point. The current naming is confusing. I only knew the
change was safe because pci_bus_new() would crash if 'parent'
wasn't a PCI_HOST_BRIDGE. But I took some time to find the other
places where PCI buses could be created, and I'm not sure yet if
I found all of them.

Is there any other code that creates TYPE_PCI_BUS objects, except
for the ones touched by this series and pci_bridge_initfn()?

pxb and pxb-pcie devices have a built-in PCI/PCIe bus,
but I saw them handled by another patch.

Reviewed-by: Marcel Apfelbaum <mar...@redhat.com>


Thanks,
Marcel

---
 hw/pci/pci.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 25118fb91d..d9535c0bdc 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -362,7 +362,7 @@ const char *pci_root_bus_path(PCIDevice *dev)
     return rootbus->qbus.name;
 }

-static void pci_bus_init(PCIBus *bus, DeviceState *parent,
+static void pci_bus_init(PCIBus *bus, PCIHostState *phb,
                          MemoryRegion *address_space_mem,
                          MemoryRegion *address_space_io,
                          uint8_t devfn_min)
@@ -375,7 +375,7 @@ static void pci_bus_init(PCIBus *bus, DeviceState *parent,
     /* host bridge */
     QLIST_INIT(&bus->child);

-    pci_host_bus_register(PCI_HOST_BRIDGE(host));
+    pci_host_bus_register(phb);
 }

 bool pci_bus_is_express(PCIBus *bus)
@@ -394,8 +394,9 @@ void pci_bus_new_inplace(PCIBus *bus, size_t bus_size, 
DeviceState *parent,
                          MemoryRegion *address_space_io,
                          uint8_t devfn_min, const char *typename)
 {
+    PCIHostState *phb = PCI_HOST_BRIDGE(parent);
     qbus_create_inplace(bus, bus_size, typename, parent, name);
-    pci_bus_init(bus, parent, address_space_mem, address_space_io, devfn_min);
+    pci_bus_init(bus, phb, address_space_mem, address_space_io, devfn_min);
 }

 PCIBus *pci_bus_new(DeviceState *parent, const char *name,
@@ -403,10 +404,11 @@ PCIBus *pci_bus_new(DeviceState *parent, const char *name,
                     MemoryRegion *address_space_io,
                     uint8_t devfn_min, const char *typename)
 {
+    PCIHostState *phb = PCI_HOST_BRIDGE(parent);
     PCIBus *bus;

     bus = PCI_BUS(qbus_create(typename, parent, name));
-    pci_bus_init(bus, parent, address_space_mem, address_space_io, devfn_min);
+    pci_bus_init(bus, phb, address_space_mem, address_space_io, devfn_min);
     return bus;
 }

--
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson