[PATCH] pci: add enforce_slot_reserved_mask_manual property

[Chuck Zmudzinski]

The current reserved slot check in do_pci_register_device(), added with
commit 8b8849844fd6, is done even if the pci device being added is
configured manually for a particular slot. The new property, when set
to false, disables the check when the device is configured to request a
particular slot. This allows an administrator or management tool to
override slot_reserved_mask for a pci device by requesting a particular
slot for the device. The new property is initialized to true which
preserves the existing behavior of slot_reserved_mask by default.

Signed-off-by: Chuck Zmudzinski <brchuckz@aol.com>
---
 hw/pci/pci.c             | 9 ++++++++-
 include/hw/pci/pci_bus.h | 1 +
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index c2fb88f9a3..5e15f08036 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -467,6 +467,7 @@ static void pci_root_bus_internal_init(PCIBus *bus, 
DeviceState *parent,
     assert(PCI_FUNC(devfn_min) == 0);
     bus->devfn_min = devfn_min;
     bus->slot_reserved_mask = 0x0;
+    bus->enforce_slot_reserved_mask_manual = true;
     bus->address_space_mem = address_space_mem;
     bus->address_space_io = address_space_io;
     bus->flags |= PCI_BUS_IS_ROOT;
@@ -1074,6 +1075,12 @@ static bool pci_bus_devfn_reserved(PCIBus *bus, int 
devfn)
     return bus->slot_reserved_mask & (1UL << PCI_SLOT(devfn));
 }
 
+static bool pci_bus_devfn_reserved_manual(PCIBus *bus, int devfn)
+{
+    return bus->enforce_slot_reserved_mask_manual &&
+            (bus->slot_reserved_mask & (1UL << PCI_SLOT(devfn)));
+}
+
 /* -1 for devfn means auto assign */
 static PCIDevice *do_pci_register_device(PCIDevice *pci_dev,
                                          const char *name, int devfn,
@@ -1107,7 +1114,7 @@ static PCIDevice *do_pci_register_device(PCIDevice 
*pci_dev,
                    "or reserved", name);
         return NULL;
     found: ;
-    } else if (pci_bus_devfn_reserved(bus, devfn)) {
+    } else if (pci_bus_devfn_reserved_manual(bus, devfn)) {
         error_setg(errp, "PCI: slot %d function %d not available for %s,"
                    " reserved",
                    PCI_SLOT(devfn), PCI_FUNC(devfn), name);
diff --git a/include/hw/pci/pci_bus.h b/include/hw/pci/pci_bus.h
index 5653175957..e0f15ee9be 100644
--- a/include/hw/pci/pci_bus.h
+++ b/include/hw/pci/pci_bus.h
@@ -37,6 +37,7 @@ struct PCIBus {
     void *iommu_opaque;
     uint8_t devfn_min;
     uint32_t slot_reserved_mask;
+    bool enforce_slot_reserved_mask_manual;
     pci_set_irq_fn set_irq;
     pci_map_irq_fn map_irq;
     pci_route_irq_fn route_intx_to_irq;
-- 
2.39.0