Commit 96dbc9af authored by Greg Kurz's avatar Greg Kurz Committed by David Gibson
Browse files

spapr_pci: don't create 64-bit MMIO window if we don't need to 



When running a pseries-2.2 or older machine type, we get the following
lines in info mtree:

address-space: memory
...
ffffffffffffffff-ffffffffffffffff (prio 0, i/o): alias
 pci@800000020000000.mmio64-alias @pci@800000020000000.mmio
  ffffffffffffffff-ffffffffffffffff

address-space: cpu-memory
...
ffffffffffffffff-ffffffffffffffff (prio 0, i/o): alias
 pci@800000020000000.mmio64-alias @pci@800000020000000.mmio
  ffffffffffffffff-ffffffffffffffff

The same thing occurs when running a pseries-2.7 with

    -global spapr-pci-host-bridge.mem_win_size=2147483648

This happens because we always create a 64-bit MMIO window, even if
we didn't explicitely requested it (ie, mem64_win_size == 0) and the
32-bit window is below 2GiB. It doesn't seem to have an impact on the
guest though because spapr_populate_pci_dt() doesn't advertise the
bogus windows when mem64_win_size == 0.

Since these memory regions don't induce any state, we can safely
choose to not create them when their address is equal to -1,
without breaking migration from existing setups.

Signed-off-by: default avatarGreg Kurz <groug@kaod.org>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent 1d36da76

hw/ppc/spapr_pci.c

+13 −7
Original line number Diff line number Diff line
@@ -1622,13 +1622,19 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp) 
    memory_region_add_subregion(get_system_memory(), sphb->mem_win_addr,

                                &sphb->mem32window);



    if (sphb->mem64_win_pciaddr != (hwaddr)-1) {

        namebuf = g_strdup_printf("%s.mmio64-alias", sphb->dtbusname);

        memory_region_init_alias(&sphb->mem64window, OBJECT(sphb),

                                 namebuf, &sphb->memspace,

                                 sphb->mem64_win_pciaddr, sphb->mem64_win_size);

        g_free(namebuf);

    memory_region_add_subregion(get_system_memory(), sphb->mem64_win_addr,



        if (sphb->mem64_win_addr != (hwaddr)-1) {

            memory_region_add_subregion(get_system_memory(),

                                        sphb->mem64_win_addr,

                                        &sphb->mem64window);

        }

    }



    /* Initialize IO regions */

    namebuf = g_strdup_printf("%s.io", sphb->dtbusname);