diff --git a/include/hw/pci/pcie_host.h b/include/hw/pci/pcie_host.h
index 076457b270..b3c8ce973c 100644
--- a/include/hw/pci/pcie_host.h
+++ b/include/hw/pci/pcie_host.h
@@ -60,7 +60,7 @@ void pcie_host_mmcfg_update(PCIExpressHost *e,
 /*
  * PCI express ECAM (Enhanced Configuration Address Mapping) format.
  * AKA mmcfg address
- * bit 20 - 28: bus number
+ * bit 20 - 27: bus number
  * bit 15 - 19: device number
  * bit 12 - 14: function number
  * bit  0 - 11: offset in configuration space of a given device
@@ -68,7 +68,7 @@ void pcie_host_mmcfg_update(PCIExpressHost *e,
 #define PCIE_MMCFG_SIZE_MAX             (1ULL << 29)
 #define PCIE_MMCFG_SIZE_MIN             (1ULL << 20)
 #define PCIE_MMCFG_BUS_BIT              20
-#define PCIE_MMCFG_BUS_MASK             0x1ff
+#define PCIE_MMCFG_BUS_MASK             0xff
 #define PCIE_MMCFG_DEVFN_BIT            12
 #define PCIE_MMCFG_DEVFN_MASK           0xff
 #define PCIE_MMCFG_CONFOFFSET_MASK      0xfff