Re: [PATCH v5 3/5] i386/pc: pass pci_hole64_size to pc_memory_init()

[Igor Mammedov]

On Fri, 20 May 2022 11:45:30 +0100
Joao Martins <joao.m.martins@oracle.com> wrote:

> Use the pre-initialized pci-host qdev and fetch the
> pci-hole64-size into pc_memory_init() newly added argument.
> piix needs a bit of care given all the !pci_enabled()
> and that the pci_hole64_size is private to i440fx.
> 
> This is in preparation to determine that host-phys-bits are
> enough and for pci-hole64-size to be considered to relocate
> ram-above-4g to be at 1T (on AMD platforms).

modulo nit blow

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

> 
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>  hw/i386/pc.c                 | 3 ++-
>  hw/i386/pc_piix.c            | 5 ++++-
>  hw/i386/pc_q35.c             | 8 +++++++-
>  hw/pci-host/i440fx.c         | 7 +++++++
>  include/hw/i386/pc.h         | 3 ++-
>  include/hw/pci-host/i440fx.h | 1 +
>  6 files changed, 23 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index f7da1d5dd40d..af52d4ff89ef 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -799,7 +799,8 @@ void xen_load_linux(PCMachineState *pcms)
>  void pc_memory_init(PCMachineState *pcms,
>                      MemoryRegion *system_memory,
>                      MemoryRegion *rom_memory,
> -                    MemoryRegion **ram_memory)
> +                    MemoryRegion **ram_memory,
> +                    uint64_t pci_hole64_size)
>  {
>      int linux_boot, i;
>      MemoryRegion *option_rom_mr;
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 12d4a279c793..57bb5b8f2aea 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;
> +    uint64_t hole64_size;

init it to 0 right here to avoid chance of run amok uninitialized variable?

>      DeviceState *i440fx_dev;
>  
>      /*
> @@ -166,10 +167,12 @@ static void pc_init1(MachineState *machine,
>          memory_region_init(pci_memory, NULL, "pci", UINT64_MAX);
>          rom_memory = pci_memory;
>          i440fx_dev = qdev_new(host_type);
> +        hole64_size = i440fx_pci_hole64_size(i440fx_dev);
>      } else {
>          pci_memory = NULL;
>          rom_memory = system_memory;
>          i440fx_dev = NULL;
> +        hole64_size = 0;
>      }
>  
>      pc_guest_info_init(pcms);
> @@ -186,7 +189,7 @@ static void pc_init1(MachineState *machine,
>      /* allocate ram and load rom/bios */
>      if (!xen_enabled()) {
>          pc_memory_init(pcms, system_memory,
> -                       rom_memory, &ram_memory);
> +                       rom_memory, &ram_memory, hole64_size);
>      } else {
>          pc_system_flash_cleanup_unused(pcms);
>          if (machine->kernel_filename != NULL) {
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 8d867bdb274a..4d5c2fbd976b 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -138,6 +138,7 @@ static void pc_q35_init(MachineState *machine)
>      MachineClass *mc = MACHINE_GET_CLASS(machine);
>      bool acpi_pcihp;
>      bool keep_pci_slot_hpc;
> +    uint64_t pci_hole64_size = 0;
>  
>      /* Check whether RAM fits below 4G (leaving 1/2 GByte for IO memory
>       * and 256 Mbytes for PCI Express Enhanced Configuration Access Mapping
> @@ -206,8 +207,13 @@ static void pc_q35_init(MachineState *machine)
>      /* create pci host bus */
>      q35_host = Q35_HOST_DEVICE(qdev_new(TYPE_Q35_HOST_DEVICE));
>  
> +    if (pcmc->pci_enabled) {
> +        pci_hole64_size = q35_host->mch.pci_hole64_size;
> +    }
> +
>      /* allocate ram and load rom/bios */
> -    pc_memory_init(pcms, get_system_memory(), rom_memory, &ram_memory);
> +    pc_memory_init(pcms, get_system_memory(), rom_memory, &ram_memory,
> +                   pci_hole64_size);
>  
>      object_property_add_child(qdev_get_machine(), "q35", OBJECT(q35_host));
>      object_property_set_link(OBJECT(q35_host), MCH_HOST_PROP_RAM_MEM,
> diff --git a/hw/pci-host/i440fx.c b/hw/pci-host/i440fx.c
> index 5c1bab5c58ed..c5cc28250d5c 100644
> --- a/hw/pci-host/i440fx.c
> +++ b/hw/pci-host/i440fx.c
> @@ -237,6 +237,13 @@ static void i440fx_realize(PCIDevice *dev, Error **errp)
>      }
>  }
>  
> +uint64_t i440fx_pci_hole64_size(DeviceState *i440fx_dev)
> +{
> +        I440FXState *i440fx = I440FX_PCI_HOST_BRIDGE(i440fx_dev);
> +
> +        return i440fx->pci_hole64_size;
> +}
> +
>  PCIBus *i440fx_init(const char *host_type, const char *pci_type,
>                      DeviceState *dev,
>                      PCII440FXState **pi440fx_state,
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index ffcac5121ed9..9c847faea2f8 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -158,7 +158,8 @@ void xen_load_linux(PCMachineState *pcms);
>  void pc_memory_init(PCMachineState *pcms,
>                      MemoryRegion *system_memory,
>                      MemoryRegion *rom_memory,
> -                    MemoryRegion **ram_memory);
> +                    MemoryRegion **ram_memory,
> +                    uint64_t pci_hole64_size);
>  uint64_t pc_pci_hole64_start(void);
>  DeviceState *pc_vga_init(ISABus *isa_bus, PCIBus *pci_bus);
>  void pc_basic_device_init(struct PCMachineState *pcms,
> diff --git a/include/hw/pci-host/i440fx.h b/include/hw/pci-host/i440fx.h
> index c4710445e30a..1299d6a2b0e4 100644
> --- a/include/hw/pci-host/i440fx.h
> +++ b/include/hw/pci-host/i440fx.h
> @@ -45,5 +45,6 @@ PCIBus *i440fx_init(const char *host_type, const char 
> *pci_type,
>                      MemoryRegion *pci_memory,
>                      MemoryRegion *ram_memory);
>  
> +uint64_t i440fx_pci_hole64_size(DeviceState *i440fx_dev);
>  
>  #endif