diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index e46f286e2422f16777ed58d6482f77a719efb82a..a051b58ba799821c8dd7d919c9cd1216b76f8b38 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -109,6 +109,16 @@ static void q35_host_get_pci_hole64_end(Object *obj, Visitor *v,
     visit_type_uint64(v, &w64.end, name, errp);
 }
 
+static void q35_host_get_mmcfg_size(Object *obj, Visitor *v,
+                                    void *opaque, const char *name,
+                                    Error **errp)
+{
+    PCIExpressHost *e = PCIE_HOST_BRIDGE(obj);
+    uint32_t value = e->size;
+
+    visit_type_uint32(v, &value, name, errp);
+}
+
 static Property mch_props[] = {
     DEFINE_PROP_UINT64(PCIE_HOST_MCFG_BASE, Q35PCIHost, parent_obj.base_addr,
                         MCH_HOST_BRIDGE_PCIEXBAR_DEFAULT),
@@ -160,6 +170,10 @@ static void q35_host_initfn(Object *obj)
                         q35_host_get_pci_hole64_end,
                         NULL, NULL, NULL, NULL);
 
+    object_property_add(obj, PCIE_HOST_MCFG_SIZE, "int",
+                        q35_host_get_mmcfg_size,
+                        NULL, NULL, NULL, NULL);
+
     /* Leave enough space for the biggest MCFG BAR */
     /* TODO: this matches current bios behaviour, but
      * it's not a power of two, which means an MTRR
diff --git a/include/hw/pci/pcie_host.h b/include/hw/pci/pcie_host.h
index 33d75bdcf6ec69ffa8c311dfee035e59eb91521d..acca45ed586b2d42955caf2d0f642071cb565fed 100644
--- a/include/hw/pci/pcie_host.h
+++ b/include/hw/pci/pcie_host.h
@@ -29,6 +29,7 @@
     OBJECT_CHECK(PCIExpressHost, (obj), TYPE_PCIE_HOST_BRIDGE)
 
 #define PCIE_HOST_MCFG_BASE "MCFG"
+#define PCIE_HOST_MCFG_SIZE "mcfg_size"
 
 /* pcie_host::base_addr == PCIE_BASE_ADDR_UNMAPPED when it isn't mapped. */
 #define PCIE_BASE_ADDR_UNMAPPED  ((hwaddr)-1ULL)