[Qemu-devel] [PATCH v3 1/2] enable multi-function hot-add

[Cao jin]

Just ensure the function 0 added last, then driver will got the notification
to scan all the function in the slot.

Signed-off-by: Cao jin <address@hidden>
---
 hw/pci/pci.c  | 10 ++++++++++
 hw/pci/pcie.c | 18 +++++++++---------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index ccea628..15b53d9 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -847,6 +847,7 @@ static PCIDevice *do_pci_register_device(PCIDevice 
*pci_dev, PCIBus *bus,
     PCIConfigWriteFunc *config_write = pc->config_write;
     Error *local_err = NULL;
     AddressSpace *dma_as;
+    DeviceState *dev = DEVICE(pci_dev);
 
     if (devfn < 0) {
         for(devfn = bus->devfn_min ; devfn < ARRAY_SIZE(bus->devices);
@@ -864,6 +865,15 @@ static PCIDevice *do_pci_register_device(PCIDevice 
*pci_dev, PCIBus *bus,
                    PCI_SLOT(devfn), PCI_FUNC(devfn), name,
                    bus->devices[devfn]->name);
         return NULL;
+    } else if (dev->hotplugged &&
+               bus->devices[PCI_DEVFN(PCI_SLOT(devfn), 0)]) {
+        error_setg(errp, "PCI: slot %d function 0 already ocuppied by %s,"
+                   " new func %s cannot be exposed to guest.",
+                   PCI_SLOT(devfn),
+                   bus->devices[PCI_DEVFN(PCI_SLOT(devfn), 0)]->name,
+                   name);
+
+       return NULL;
     }
 
     pci_dev->bus = bus;
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 6e28985..89bf61b 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -249,16 +249,16 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler 
*hotplug_dev, DeviceState *dev,
         return;
     }
 
-    /* TODO: multifunction hot-plug.
-     * Right now, only a device of function = 0 is allowed to be
-     * hot plugged/unplugged.
+    /* To enable multifunction hot-plug, we just ensure the function
+     * 0 added last. Until function 0 added, we set the sltsta and
+     * inform OS via event notification.
      */
-    assert(PCI_FUNC(pci_dev->devfn) == 0);
-
-    pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
-                               PCI_EXP_SLTSTA_PDS);
-    pcie_cap_slot_event(PCI_DEVICE(hotplug_dev),
-                        PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP);
+    if (PCI_FUNC(pci_dev->devfn) == 0) {
+        pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
+                                   PCI_EXP_SLTSTA_PDS);
+        pcie_cap_slot_event(PCI_DEVICE(hotplug_dev),
+                            PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP);
+    }
 }
 
 void pcie_cap_slot_hot_unplug_request_cb(HotplugHandler *hotplug_dev,
-- 
2.1.0