diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index e1a9fd7ff3..7a1b8c6f45 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1759,11 +1759,22 @@ static const TypeInfo spapr_machine_info = {
     },
 };
 
+#define SPAPR_COMPAT_2_2 \
+        {\
+            .driver   = TYPE_SPAPR_PCI_HOST_BRIDGE,\
+            .property = "mem_win_size",\
+            .value    = "0x20000000",\
+        }
+
+#define SPAPR_COMPAT_2_1 \
+        SPAPR_COMPAT_2_2
+
 static void spapr_machine_2_1_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
     static GlobalProperty compat_props[] = {
         HW_COMPAT_2_1,
+        SPAPR_COMPAT_2_1,
         { /* end of list */ }
     };
 
@@ -1780,10 +1791,15 @@ static const TypeInfo spapr_machine_2_1_info = {
 
 static void spapr_machine_2_2_class_init(ObjectClass *oc, void *data)
 {
+    static GlobalProperty compat_props[] = {
+        SPAPR_COMPAT_2_2,
+        { /* end of list */ }
+    };
     MachineClass *mc = MACHINE_CLASS(oc);
 
     mc->name = "pseries-2.2";
     mc->desc = "pSeries Logical Partition (PAPR compliant) v2.2";
+    mc->compat_props = compat_props;
 }
 
 static const TypeInfo spapr_machine_2_2_info = {
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 6deeb19e3f..cebdeb3516 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -868,6 +868,10 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
     int bus_off, i, j;
     char nodename[256];
     uint32_t bus_range[] = { cpu_to_be32(0), cpu_to_be32(0xff) };
+    const uint64_t mmiosize = memory_region_size(&phb->memwindow);
+    const uint64_t w32max = (1ULL << 32) - SPAPR_PCI_MEM_WIN_BUS_OFFSET;
+    const uint64_t w32size = MIN(w32max, mmiosize);
+    const uint64_t w64size = (mmiosize > w32size) ? (mmiosize - w32size) : 0;
     struct {
         uint32_t hi;
         uint64_t child;
@@ -882,9 +886,15 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
         {
             cpu_to_be32(b_ss(2)), cpu_to_be64(SPAPR_PCI_MEM_WIN_BUS_OFFSET),
             cpu_to_be64(phb->mem_win_addr),
-            cpu_to_be64(memory_region_size(&phb->memwindow)),
+            cpu_to_be64(w32size),
+        },
+        {
+            cpu_to_be32(b_ss(3)), cpu_to_be64(1ULL << 32),
+            cpu_to_be64(phb->mem_win_addr + w32size),
+            cpu_to_be64(w64size)
         },
     };
+    const unsigned sizeof_ranges = (w64size ? 3 : 2) * sizeof(ranges[0]);
     uint64_t bus_reg[] = { cpu_to_be64(phb->buid), 0 };
     uint32_t interrupt_map_mask[] = {
         cpu_to_be32(b_ddddd(-1)|b_fff(0)), 0x0, 0x0, cpu_to_be32(-1)};
@@ -913,7 +923,7 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
     _FDT(fdt_setprop_cell(fdt, bus_off, "#interrupt-cells", 0x1));
     _FDT(fdt_setprop(fdt, bus_off, "used-by-rtas", NULL, 0));
     _FDT(fdt_setprop(fdt, bus_off, "bus-range", &bus_range, sizeof(bus_range)));
-    _FDT(fdt_setprop(fdt, bus_off, "ranges", &ranges, sizeof(ranges)));
+    _FDT(fdt_setprop(fdt, bus_off, "ranges", &ranges, sizeof_ranges));
     _FDT(fdt_setprop(fdt, bus_off, "reg", &bus_reg, sizeof(bus_reg)));
     _FDT(fdt_setprop_cell(fdt, bus_off, "ibm,pci-config-space-type", 0x1));
     _FDT(fdt_setprop_cell(fdt, bus_off, "ibm,pe-total-#msi", XICS_IRQS));
diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
index 876ecf09ea..d725f0e42b 100644
--- a/include/hw/pci-host/spapr.h
+++ b/include/hw/pci-host/spapr.h
@@ -98,17 +98,18 @@ struct sPAPRPHBVFIOState {
 
 #define SPAPR_PCI_BASE_BUID          0x800000020000000ULL
 
+#define SPAPR_PCI_MEM_WIN_BUS_OFFSET 0x80000000ULL
+
 #define SPAPR_PCI_WINDOW_BASE        0x10000000000ULL
 #define SPAPR_PCI_WINDOW_SPACING     0x1000000000ULL
 #define SPAPR_PCI_MMIO_WIN_OFF       0xA0000000
-#define SPAPR_PCI_MMIO_WIN_SIZE      0x20000000
+#define SPAPR_PCI_MMIO_WIN_SIZE      (SPAPR_PCI_WINDOW_SPACING - \
+                                     SPAPR_PCI_MEM_WIN_BUS_OFFSET)
 #define SPAPR_PCI_IO_WIN_OFF         0x80000000
 #define SPAPR_PCI_IO_WIN_SIZE        0x10000
 
 #define SPAPR_PCI_MSI_WINDOW         0x40000000000ULL
 
-#define SPAPR_PCI_MEM_WIN_BUS_OFFSET 0x80000000ULL
-
 static inline qemu_irq spapr_phb_lsi_qirq(struct sPAPRPHBState *phb, int pin)
 {
     return xics_get_qirq(spapr->icp, phb->lsi_table[pin].irq);