diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index def5000e7b..8a87ccc8b0 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -1116,6 +1116,21 @@ static bool pci_bus_devfn_reserved(PCIBus *bus, int devfn)
     return bus->slot_reserved_mask & (1UL << PCI_SLOT(devfn));
 }
 
+uint32_t pci_bus_get_slot_reserved_mask(PCIBus *bus)
+{
+    return bus->slot_reserved_mask;
+}
+
+void pci_bus_set_slot_reserved_mask(PCIBus *bus, uint32_t mask)
+{
+    bus->slot_reserved_mask |= mask;
+}
+
+void pci_bus_clear_slot_reserved_mask(PCIBus *bus, uint32_t mask)
+{
+    bus->slot_reserved_mask &= ~mask;
+}
+
 /* -1 for devfn means auto assign */
 static PCIDevice *do_pci_register_device(PCIDevice *pci_dev,
                                          const char *name, int devfn,
diff --git a/hw/sparc64/sun4u.c b/hw/sparc64/sun4u.c
index a25e951f9d..eae7589462 100644
--- a/hw/sparc64/sun4u.c
+++ b/hw/sparc64/sun4u.c
@@ -31,7 +31,6 @@
 #include "hw/irq.h"
 #include "hw/pci/pci.h"
 #include "hw/pci/pci_bridge.h"
-#include "hw/pci/pci_bus.h"
 #include "hw/pci/pci_host.h"
 #include "hw/qdev-properties.h"
 #include "hw/pci-host/sabre.h"
@@ -608,9 +607,9 @@ static void sun4uv_init(MemoryRegion *address_space_mem,
     /* Only in-built Simba APBs can exist on the root bus, slot 0 on busA is
        reserved (leaving no slots free after on-board devices) however slots
        0-3 are free on busB */
-    pci_bus->slot_reserved_mask = 0xfffffffc;
-    pci_busA->slot_reserved_mask = 0xfffffff1;
-    pci_busB->slot_reserved_mask = 0xfffffff0;
+    pci_bus_set_slot_reserved_mask(pci_bus, 0xfffffffc);
+    pci_bus_set_slot_reserved_mask(pci_busA, 0xfffffff1);
+    pci_bus_set_slot_reserved_mask(pci_busB, 0xfffffff0);
 
     ebus = pci_new_multifunction(PCI_DEVFN(1, 0), true, TYPE_EBUS);
     qdev_prop_set_uint64(DEVICE(ebus), "console-serial-base",
diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index 2d33d178ad..a540149639 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -57,7 +57,6 @@
 #include <sys/ioctl.h>
 
 #include "hw/pci/pci.h"
-#include "hw/pci/pci_bus.h"
 #include "hw/qdev-properties.h"
 #include "hw/qdev-properties-system.h"
 #include "xen_pt.h"
@@ -951,7 +950,7 @@ void xen_igd_reserve_slot(PCIBus *pci_bus)
     }
 
     XEN_PT_LOG(0, "Reserving PCI slot 2 for IGD\n");
-    pci_bus->slot_reserved_mask |= XEN_PCI_IGD_SLOT_MASK;
+    pci_bus_set_slot_reserved_mask(pci_bus, XEN_PCI_IGD_SLOT_MASK);
 }
 
 static void xen_igd_clear_slot(DeviceState *qdev, Error **errp)
@@ -971,7 +970,7 @@ static void xen_igd_clear_slot(DeviceState *qdev, Error **errp)
         return;
     }
 
-    if (!(pci_bus->slot_reserved_mask & XEN_PCI_IGD_SLOT_MASK)) {
+    if (!(pci_bus_get_slot_reserved_mask(pci_bus) & XEN_PCI_IGD_SLOT_MASK)) {
         xpdc->pci_qdev_realize(qdev, errp);
         return;
     }
@@ -982,7 +981,7 @@ static void xen_igd_clear_slot(DeviceState *qdev, Error **errp)
         s->real_device.dev == XEN_PCI_IGD_DEV &&
         s->real_device.func == XEN_PCI_IGD_FN &&
         s->real_device.vendor_id == PCI_VENDOR_ID_INTEL) {
-        pci_bus->slot_reserved_mask &= ~XEN_PCI_IGD_SLOT_MASK;
+        pci_bus_clear_slot_reserved_mask(pci_bus, XEN_PCI_IGD_SLOT_MASK);
         XEN_PT_LOG(pci_dev, "Intel IGD found, using slot 2\n");
     }
     xpdc->pci_qdev_realize(qdev, errp);
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index d5a40cd058..935b4b91b4 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -287,6 +287,9 @@ void pci_bus_irqs(PCIBus *bus, pci_set_irq_fn set_irq,
 void pci_bus_map_irqs(PCIBus *bus, pci_map_irq_fn map_irq);
 void pci_bus_irqs_cleanup(PCIBus *bus);
 int pci_bus_get_irq_level(PCIBus *bus, int irq_num);
+uint32_t pci_bus_get_slot_reserved_mask(PCIBus *bus);
+void pci_bus_set_slot_reserved_mask(PCIBus *bus, uint32_t mask);
+void pci_bus_clear_slot_reserved_mask(PCIBus *bus, uint32_t mask);
 /* 0 <= pin <= 3 0 = INTA, 1 = INTB, 2 = INTC, 3 = INTD */
 static inline int pci_swizzle(int slot, int pin)
 {