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

[Igor Mammedov]

On Fri, 17 Jun 2022 12:13:45 +0100
Joao Martins <joao.m.martins@oracle.com> wrote:

> On 6/16/22 14:30, 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>
> >   
> 
> I haven't tackled the initialization nit below but I would assume
> you agree with the rest of the patch. Let me know if I should still
> add the Rb tag.

My ack still stands
 
> >>
> >> 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 haven't done this given that mst disagreed, plus the fact that the code 
> style of
> the function seems to place the NULL initialization mostly left to else 
> conditional
> clause. Part of the reason I haven't inited @i440fx_dev to NULL here as well 
> (now
> i440fx_host. The location we use hole64_size is also the same location we are 
> using
> @i440fx_host.
> 
> >>      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  
> >   
>