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

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Jun 16, 2022 at 03:30:14PM +0200, Igor Mammedov wrote:
> 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?


I don't see why we should, compilers seems to be pretty good about warning
about these things nowdays.

> >      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