i386/pc: create pci-host qdev prior to pc_memory_init()

At the start of pc_memory_init() we usually pass a range of
0..UINT64_MAX as pci_memory, when really its 2G (i440fx) or
32G (q35). To get the real user value, we need to get pci-host
passed property for default pci_hole64_size. Thus to get that,
create the qdev prior to memory init to better make estimations
on max used/phys addr.

This is in preparation to determine that host-phys-bits are
enough and also for pci-hole64-size to be considered to relocate
ram-above-4g to be at 1T (on AMD platforms).

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20220719170014.27028-3-joao.m.martins@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/pc_piix.c

@@ -91,6 +91,7 @@ static void pc_init1(MachineState *machine,
     MemoryRegion *pci_memory;
     MemoryRegion *rom_memory;
     ram_addr_t lowmem;
+    DeviceState *i440fx_host;
 
     /*
      * Calculate ram split, for memory below and above 4G.  It's a bit
@@ -164,9 +165,11 @@ static void pc_init1(MachineState *machine,
         pci_memory = g_new(MemoryRegion, 1);
         memory_region_init(pci_memory, NULL, "pci", UINT64_MAX);
         rom_memory = pci_memory;
+        i440fx_host = qdev_new(host_type);
     } else {
         pci_memory = NULL;
         rom_memory = system_memory;
+        i440fx_host = NULL;
     }
 
     pc_guest_info_init(pcms);
@@ -200,8 +203,8 @@ static void pc_init1(MachineState *machine,
         const char *type = xen_enabled() ? TYPE_PIIX3_XEN_DEVICE
                                          : TYPE_PIIX3_DEVICE;
 
-        pci_bus = i440fx_init(host_type,
-                              pci_type,
+        pci_bus = i440fx_init(pci_type,
+                              i440fx_host,
                               system_memory, system_io, machine->ram_size,
                               x86ms->below_4g_mem_size,
                               x86ms->above_4g_mem_size,

hw/i386/pc_q35.c

@@ -203,12 +203,12 @@ static void pc_q35_init(MachineState *machine)
                             pcms->smbios_entry_point_type);
     }
 
-    /* allocate ram and load rom/bios */
-    pc_memory_init(pcms, get_system_memory(), rom_memory, &ram_memory);
-
     /* create pci host bus */
     q35_host = Q35_HOST_DEVICE(qdev_new(TYPE_Q35_HOST_DEVICE));
 
+    /* allocate ram and load rom/bios */
+    pc_memory_init(pcms, get_system_memory(), rom_memory, &ram_memory);
+
     object_property_add_child(qdev_get_machine(), "q35", OBJECT(q35_host));
     object_property_set_link(OBJECT(q35_host), MCH_HOST_PROP_RAM_MEM,
                              OBJECT(ram_memory), NULL);

hw/pci-host/i440fx.c

@@ -237,7 +237,8 @@ static void i440fx_realize(PCIDevice *dev, Error **errp)
     }
 }
 
-PCIBus *i440fx_init(const char *host_type, const char *pci_type,
+PCIBus *i440fx_init(const char *pci_type,
+                    DeviceState *dev,
                     MemoryRegion *address_space_mem,
                     MemoryRegion *address_space_io,
                     ram_addr_t ram_size,
@@ -246,15 +247,13 @@ PCIBus *i440fx_init(const char *host_type, const char *pci_type,
                     MemoryRegion *pci_address_space,
                     MemoryRegion *ram_memory)
 {
-    DeviceState *dev;
     PCIBus *b;
     PCIDevice *d;
     PCIHostState *s;
     PCII440FXState *f;
     unsigned i;
     I440FXState *i440fx;
 
-    dev = qdev_new(host_type);
     s = PCI_HOST_BRIDGE(dev);
     b = pci_root_bus_new(dev, NULL, pci_address_space,
                          address_space_io, 0, TYPE_PCI_BUS);

include/hw/pci-host/i440fx.h

@@ -35,7 +35,8 @@ struct PCII440FXState {
 
 #define TYPE_IGD_PASSTHROUGH_I440FX_PCI_DEVICE "igd-passthrough-i440FX"
 
-PCIBus *i440fx_init(const char *host_type, const char *pci_type,
+PCIBus *i440fx_init(const char *pci_type,
+                    DeviceState *dev,
                     MemoryRegion *address_space_mem,
                     MemoryRegion *address_space_io,
                     ram_addr_t ram_size,