pseries: Don't expose PCIe extended config space on older machine types

bb9986452 "spapr_pci: Advertise access to PCIe extended config space"
allowed guests to access the extended config space of PCI Express devices
via the PAPR interfaces, even though the paravirtualized bus mostly acts
like plain PCI.

However, that patch enabled access unconditionally, including for existing
machine types, which is an unwise change in behaviour.  This patch limits
the change to pseries-2.9 (and later) machine types.

Suggested-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

3 files changed, 12 insertions, 3 deletions

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index c3bb991605..6ee566d658 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -3163,8 +3163,13 @@ DEFINE_SPAPR_MACHINE(2_9, "2.9", true);
 /*
  * pseries-2.8
  */
-#define SPAPR_COMPAT_2_8                            \
-    HW_COMPAT_2_8
+#define SPAPR_COMPAT_2_8                                        \
+    HW_COMPAT_2_8                                               \
+    {                                                           \
+        .driver   = TYPE_SPAPR_PCI_HOST_BRIDGE,                 \
+        .property = "pcie-extended-configuration-space",        \
+        .value    = "off",                                      \
+    },
 
 static void spapr_machine_2_8_instance_options(MachineState *machine)
 {
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 919d3c2c59..98c52e411f 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -1321,7 +1321,7 @@ static int spapr_populate_pci_child_dt(PCIDevice *dev, void *fdt, int offset,
     _FDT(fdt_setprop(fdt, offset, "assigned-addresses",
                      (uint8_t *)rp.assigned, rp.assigned_len));
 
-    if (pci_is_express(dev)) {
+    if (sphb->pcie_ecs && pci_is_express(dev)) {
         _FDT(fdt_setprop_cell(fdt, offset, "ibm,pci-config-space-type", 0x1));
     }
 
@@ -1858,6 +1858,8 @@ static Property spapr_phb_properties[] = {
     DEFINE_PROP_UINT32("numa_node", sPAPRPHBState, numa_node, -1),
     DEFINE_PROP_BOOL("pre-2.8-migration", sPAPRPHBState,
                      pre_2_8_migration, false),
+    DEFINE_PROP_BOOL("pcie-extended-configuration-space", sPAPRPHBState,
+                     pcie_ecs, true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
index dfa76143f3..1c2e970da2 100644
--- a/include/hw/pci-host/spapr.h
+++ b/include/hw/pci-host/spapr.h
@@ -80,6 +80,8 @@ struct sPAPRPHBState {
 
     uint32_t numa_node;
 
+    bool pcie_ecs; /* Allow access to PCIe extended config space? */
+
     /* Fields for migration compatibility hacks */
     bool pre_2_8_migration;
     uint32_t mig_liobn;