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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: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Greg Kurz 2017-09-11 12:14:19 +02:00 committed by David Gibson
parent 1d36da769a
commit 96dbc9af35
1 changed files with 13 additions and 7 deletions
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20
hw/ppc/spapr_pci.c
View File

@ -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);
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,
&sphb->mem64window);
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);
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);