ppc/pnv: Remove user-created PHB{3,4,5} devices

On a real system with POWER{8,9,10} processors, PHBs are sub-units of
the processor, they can be deactivated by firmware but not plugged in
or out like a PCI adapter on a slot. Nevertheless, having user-created
PHBs in QEMU seemed to be a good idea for testing purposes :

 1. having a limited set of PHBs speedups boot time.
 2. it is useful to be able to mimic a partially broken topology you
    some time have to deal with during bring-up.

PowerNV is also used for distro install tests and having libvirt
support eases these tasks. libvirt prefers to run the machine with
-nodefaults to be sure not to drag unexpected devices which would need
to be defined in the domain file without being specified on the QEMU
command line. For this reason :

 3. -nodefaults should not include default PHBs

User-created PHB{3,4,5} devices satisfied all these needs but reality
proves to be a bit more complex, internally when modeling such
devices, and externally when dealing with the user interface.

Req 1. and 2. can be simply addressed differently with a machine option:
"phb-mask=<uint>", which QEMU would use to enable/disable PHB device
nodes when creating the device tree.

For Req 3., we need to make sure we are taking the right approach. It
seems that we should expose a new type of user-created PHB device, a
generic virtualized one, that libvirt would use and not one depending
on the processor revision. This needs more thinking.

For now, remove user-created PHB{3,4,5} devices. All the cleanups we
did are not lost and they will be useful for the next steps.

Fixes: 5bc67b052b51 ("ppc/pnv: Introduce user creatable pnv-phb4 devices")
Fixes: 1f6a88fffc75 ("ppc/pnv: Introduce support for user created PHB3 devices")
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20220314130514.529931-1-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

1 files changed, 3 insertions, 30 deletions

diff --git a/hw/pci-host/pnv_phb3.c b/hw/pci-host/pnv_phb3.c
index aafd46b635..ac801ac835 100644
--- a/hw/pci-host/pnv_phb3.c
+++ b/hw/pci-host/pnv_phb3.c
@@ -994,30 +994,6 @@ static void pnv_phb3_realize(DeviceState *dev, Error **errp)
     PnvMachineState *pnv = PNV_MACHINE(qdev_get_machine());
     int i;
 
-    /* User created devices */
-    if (!phb->chip) {
-        Error *local_err = NULL;
-        BusState *s;
-
-        phb->chip = pnv_get_chip(pnv, phb->chip_id);
-        if (!phb->chip) {
-            error_setg(errp, "invalid chip id: %d", phb->chip_id);
-            return;
-        }
-
-        /*
-         * Reparent user created devices to the chip to build
-         * correctly the device tree.
-         */
-        pnv_chip_parent_fixup(phb->chip, OBJECT(phb), phb->phb_id);
-
-        s = qdev_get_parent_bus(DEVICE(phb->chip));
-        if (!qdev_set_parent_bus(DEVICE(phb), s, &local_err)) {
-            error_propagate(errp, local_err);
-            return;
-        }
-    }
-
     if (phb->phb_id >= PNV_CHIP_GET_CLASS(phb->chip)->num_phbs) {
         error_setg(errp, "invalid PHB index: %d", phb->phb_id);
         return;
@@ -1077,10 +1053,7 @@ static void pnv_phb3_realize(DeviceState *dev, Error **errp)
 
     pci_setup_iommu(pci->bus, pnv_phb3_dma_iommu, phb);
 
-    if (defaults_enabled()) {
-        pnv_phb_attach_root_port(PCI_HOST_BRIDGE(phb),
-                                 TYPE_PNV_PHB3_ROOT_PORT);
-    }
+    pnv_phb_attach_root_port(PCI_HOST_BRIDGE(phb), TYPE_PNV_PHB3_ROOT_PORT);
 }
 
 void pnv_phb3_update_regions(PnvPHB3 *phb)
@@ -1131,7 +1104,7 @@ static void pnv_phb3_class_init(ObjectClass *klass, void *data)
     dc->realize = pnv_phb3_realize;
     device_class_set_props(dc, pnv_phb3_properties);
     set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
-    dc->user_creatable = true;
+    dc->user_creatable = false;
 }
 
 static const TypeInfo pnv_phb3_type_info = {
@@ -1201,7 +1174,7 @@ static void pnv_phb3_root_port_class_init(ObjectClass *klass, void *data)
 
     device_class_set_parent_realize(dc, pnv_phb3_root_port_realize,
                                     &rpc->parent_realize);
-    dc->user_creatable = true;
+    dc->user_creatable = false;
 
     k->vendor_id = PCI_VENDOR_ID_IBM;
     k->device_id = 0x03dc;