diff --git a/hw/pci/pci_host.c b/hw/pci/pci_host.c
index 0958d157de..ce7bcdb1d5 100644
--- a/hw/pci/pci_host.c
+++ b/hw/pci/pci_host.c
@@ -106,7 +106,7 @@ uint32_t pci_host_config_read_common(PCIDevice *pci_dev, uint32_t addr,
     return ret;
 }
 
-void pci_data_write(PCIBus *s, uint32_t addr, uint32_t val, int len)
+void pci_data_write(PCIBus *s, uint32_t addr, uint32_t val, unsigned len)
 {
     PCIDevice *pci_dev = pci_dev_find_by_addr(s, addr);
     uint32_t config_addr = addr & (PCI_CONFIG_SPACE_SIZE - 1);
@@ -119,7 +119,7 @@ void pci_data_write(PCIBus *s, uint32_t addr, uint32_t val, int len)
                                  val, len);
 }
 
-uint32_t pci_data_read(PCIBus *s, uint32_t addr, int len)
+uint32_t pci_data_read(PCIBus *s, uint32_t addr, unsigned len)
 {
     PCIDevice *pci_dev = pci_dev_find_by_addr(s, addr);
     uint32_t config_addr = addr & (PCI_CONFIG_SPACE_SIZE - 1);
diff --git a/include/hw/pci/pci_host.h b/include/hw/pci/pci_host.h
index ba31595fc7..9ce088bd13 100644
--- a/include/hw/pci/pci_host.h
+++ b/include/hw/pci/pci_host.h
@@ -62,8 +62,8 @@ void pci_host_config_write_common(PCIDevice *pci_dev, uint32_t addr,
 uint32_t pci_host_config_read_common(PCIDevice *pci_dev, uint32_t addr,
                                      uint32_t limit, uint32_t len);
 
-void pci_data_write(PCIBus *s, uint32_t addr, uint32_t val, int len);
-uint32_t pci_data_read(PCIBus *s, uint32_t addr, int len);
+void pci_data_write(PCIBus *s, uint32_t addr, uint32_t val, unsigned len);
+uint32_t pci_data_read(PCIBus *s, uint32_t addr, unsigned len);
 
 extern const MemoryRegionOps pci_host_conf_le_ops;
 extern const MemoryRegionOps pci_host_conf_be_ops;