When the size of the physical address space is known (PhysBits is not
zero) move the 64bit pci io window to the end of the address space.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 src/fw/pciinit.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index badf13d3233b..0fcd2be598a2 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -1128,6 +1128,14 @@ static void pci_bios_map_devices(struct pci_bus *busses)
         r64_mem.base = le64_to_cpu(romfile_loadint("etc/reserved-memory-end", 0));
         if (r64_mem.base < 0x100000000LL + RamSizeOver4G)
             r64_mem.base = 0x100000000LL + RamSizeOver4G;
+        if (CPUPhysBits) {
+            u64 top = 1LL << CPUPhysBits;
+            u64 size = (ALIGN(sum_mem, (1LL<<30)) +
+                        ALIGN(sum_pref, (1LL<<30)));
+            if (r64_mem.base < top - size) {
+                r64_mem.base = top - size;
+            }
+        }
         r64_mem.base = ALIGN(r64_mem.base, align_mem);
         r64_mem.base = ALIGN(r64_mem.base, (1LL<<30));    // 1G hugepage
         r64_pref.base = r64_mem.base + sum_mem;
-- 
2.41.0