Re: [PATCH v5 2/5] i386/pc: create pci-host qdev prior to pc_memory_init()

["Reviewed-by: Igor Mammedov" <imammedo@redhat.com>]

On Fri, 20 May 2022 11:45:29 +0100
Joao Martins <joao.m.martins@oracle.com> wrote:

> 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).

with comments below fixed
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
 
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>  hw/i386/pc_piix.c            | 5 ++++-
>  hw/i386/pc_q35.c             | 6 +++---
>  hw/pci-host/i440fx.c         | 3 +--
>  include/hw/pci-host/i440fx.h | 2 +-
>  4 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 578e537b3525..12d4a279c793 100644
> --- a/hw/i386/pc_piix.c
> +++ b/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_dev;
>  
>      /*
>       * 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_dev = qdev_new(host_type);
>      } else {
>          pci_memory = NULL;
>          rom_memory = system_memory;
> +        i440fx_dev = NULL;
>      }
>  
>      pc_guest_info_init(pcms);
> @@ -199,7 +202,7 @@ static void pc_init1(MachineState *machine,
>  
>          pci_bus = i440fx_init(host_type,
>                                pci_type,
> -                              &i440fx_state,
> +                              i440fx_dev, &i440fx_state,
confusing names, suggest to rename i440fx_state -> pci_i440fx and i440fx_dev -> i440fx_host
or something like this

>                                system_memory, system_io, machine->ram_size,
>                                x86ms->below_4g_mem_size,
>                                x86ms->above_4g_mem_size,
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 42eb8b97079a..8d867bdb274a 100644
> --- a/hw/i386/pc_q35.c
> +++ b/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);
> diff --git a/hw/pci-host/i440fx.c b/hw/pci-host/i440fx.c
> index e08716142b6e..5c1bab5c58ed 100644
> --- a/hw/pci-host/i440fx.c
> +++ b/hw/pci-host/i440fx.c
> @@ -238,6 +238,7 @@ static void i440fx_realize(PCIDevice *dev, Error **errp)
>  }
>  
>  PCIBus *i440fx_init(const char *host_type, const char *pci_type,

does it still need 'host_type'?

> +                    DeviceState *dev,
>                      PCII440FXState **pi440fx_state,
>                      MemoryRegion *address_space_mem,
>                      MemoryRegion *address_space_io,
> @@ -247,7 +248,6 @@ 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;
> @@ -255,7 +255,6 @@ PCIBus *i440fx_init(const char *host_type, const char *pci_type,
>      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);
> diff --git a/include/hw/pci-host/i440fx.h b/include/hw/pci-host/i440fx.h
> index f068aaba8fda..c4710445e30a 100644
> --- a/include/hw/pci-host/i440fx.h
> +++ b/include/hw/pci-host/i440fx.h
> @@ -36,7 +36,7 @@ struct PCII440FXState {
>  #define TYPE_IGD_PASSTHROUGH_I440FX_PCI_DEVICE "igd-passthrough-i440FX"
>  
>  PCIBus *i440fx_init(const char *host_type, const char *pci_type,
> -                    PCII440FXState **pi440fx_state,
> +                    DeviceState *dev, PCII440FXState **pi440fx_state,
>                      MemoryRegion *address_space_mem,
>                      MemoryRegion *address_space_io,
>                      ram_addr_t ram_size,