Re: [RFC PATCH v3 08/19] pc: calculate dimm physical addresses and adjust memory map

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On Fri, Sep 21, 2012 at 11:17 AM, Vasilis Liaskovitis
<vasilis.liaskovitis@xxxxxxxxxxxxxxxx> wrote:
> Dimm physical address offsets are calculated automatically and memory map is
> adjusted accordingly. If a DIMM can fit before the PCI_HOLE_START (currently
> 0xe0000000), it will be added normally, otherwise its physical address will be
> above 4GB.
>
> Also create memory bus on i440fx-pcihost device.
>
> Signed-off-by: Vasilis Liaskovitis <vasilis.liaskovitis@xxxxxxxxxxxxxxxx>
> ---
>  hw/pc.c      |   41 +++++++++++++++++++++++++++++++++++++++++
>  hw/pc.h      |    6 ++++++
>  hw/pc_piix.c |   20 ++++++++++++++------
>  vl.c         |    1 +
>  4 files changed, 62 insertions(+), 6 deletions(-)
>
> diff --git a/hw/pc.c b/hw/pc.c
> index 112739a..2c9664d 100644
> --- a/hw/pc.c
> +++ b/hw/pc.c
> @@ -52,6 +52,7 @@
>  #include "arch_init.h"
>  #include "bitmap.h"
>  #include "vga-pci.h"
> +#include "dimm.h"
>
>  /* output Bochs bios info messages */
>  //#define DEBUG_BIOS
> @@ -93,6 +94,9 @@ struct e820_table {
>  static struct e820_table e820_table;
>  struct hpet_fw_config hpet_cfg = {.count = UINT8_MAX};
>
> +ram_addr_t below_4g_hp_mem_size = 0;
> +ram_addr_t above_4g_hp_mem_size = 0;
> +extern target_phys_addr_t ram_hp_offset;

extern declarations belong to headers only.

>  void gsi_handler(void *opaque, int n, int level)
>  {
>      GSIState *s = opaque;
> @@ -1160,3 +1164,40 @@ void pc_pci_device_init(PCIBus *pci_bus)
>          pci_create_simple(pci_bus, -1, "lsi53c895a");
>      }
>  }
> +
> +
> +/* Function to configure memory offsets of hotpluggable dimms */
> +
> +target_phys_addr_t pc_set_hp_memory_offset(uint64_t size)
> +{
> +    target_phys_addr_t ret;
> +
> +    /* on first call, initialize ram_hp_offset */
> +    if (!ram_hp_offset) {
> +        if (ram_size >= PCI_HOLE_START ) {
> +            ram_hp_offset = 0x100000000LL + (ram_size - PCI_HOLE_START);
> +        } else {
> +            ram_hp_offset = ram_size;
> +        }
> +    }
> +
> +    if (ram_hp_offset >= 0x100000000LL) {
> +        ret = ram_hp_offset;
> +        above_4g_hp_mem_size += size;
> +        ram_hp_offset += size;
> +    }
> +    /* if dimm fits before pci hole, append it normally */
> +    else if (ram_hp_offset + size <= PCI_HOLE_START) {

} else if ...

> +        ret = ram_hp_offset;
> +        below_4g_hp_mem_size += size;
> +        ram_hp_offset += size;
> +    }
> +    /* otherwise place it above 4GB */
> +    else {

} else {

> +        ret = 0x100000000LL;
> +        above_4g_hp_mem_size += size;
> +        ram_hp_offset = 0x100000000LL + size;
> +    }
> +
> +    return ret;
> +}

But the function and use of lots of global variables is ugly. The dimm
devices should be just created in piix_pci.c (i440fx) directly with
correct offsets and sizes, so all  below_4g_mem_size etc. calculations
should be moved there. That would implement the PMC part of i440fx.

For ISA PC, probably the board should create the DIMMs since there may
not be a memory controller. The >4G logic does not make sense there
anyway.

> diff --git a/hw/pc.h b/hw/pc.h
> index e4db071..f3304fc 100644
> --- a/hw/pc.h
> +++ b/hw/pc.h
> @@ -10,6 +10,7 @@
>  #include "memory.h"
>  #include "ioapic.h"
>
> +#define PCI_HOLE_START 0xe0000000
>  /* PC-style peripherals (also used by other machines).  */
>
>  /* serial.c */
> @@ -214,6 +215,11 @@ static inline bool isa_ne2000_init(ISABus *bus, int base, int irq, NICInfo *nd)
>  /* pc_sysfw.c */
>  void pc_system_firmware_init(MemoryRegion *rom_memory);
>
> +/* memory hotplug */
> +target_phys_addr_t pc_set_hp_memory_offset(uint64_t size);
> +extern ram_addr_t below_4g_hp_mem_size;
> +extern ram_addr_t above_4g_hp_mem_size;
> +
>  /* e820 types */
>  #define E820_RAM        1
>  #define E820_RESERVED   2
> diff --git a/hw/pc_piix.c b/hw/pc_piix.c
> index 88ff041..d1fd276 100644
> --- a/hw/pc_piix.c
> +++ b/hw/pc_piix.c
> @@ -43,6 +43,7 @@
>  #include "xen.h"
>  #include "memory.h"
>  #include "exec-memory.h"
> +#include "dimm.h"
>  #ifdef CONFIG_XEN
>  #  include <xen/hvm/hvm_info_table.h>
>  #endif
> @@ -155,9 +156,9 @@ static void pc_init1(MemoryRegion *system_memory,
>          kvmclock_create();
>      }
>
> -    if (ram_size >= 0xe0000000 ) {
> -        above_4g_mem_size = ram_size - 0xe0000000;
> -        below_4g_mem_size = 0xe0000000;
> +    if (ram_size >= PCI_HOLE_START ) {
> +        above_4g_mem_size = ram_size - PCI_HOLE_START;
> +        below_4g_mem_size = PCI_HOLE_START;
>      } else {
>          above_4g_mem_size = 0;
>          below_4g_mem_size = ram_size;
> @@ -172,6 +173,9 @@ static void pc_init1(MemoryRegion *system_memory,
>          rom_memory = system_memory;
>      }
>
> +    /* adjust memory map for hotplug dimms */
> +    dimm_calc_offsets(pc_set_hp_memory_offset);
> +
>      /* allocate ram and load rom/bios */
>      if (!xen_enabled()) {
>          fw_cfg = pc_memory_init(system_memory,
> @@ -192,9 +196,11 @@ static void pc_init1(MemoryRegion *system_memory,
>      if (pci_enabled) {
>          pci_bus = i440fx_init(&i440fx_state, &piix3_devfn, &isa_bus, gsi,
>                                system_memory, system_io, ram_size,
> -                              below_4g_mem_size,
> -                              0x100000000ULL - below_4g_mem_size,
> -                              0x100000000ULL + above_4g_mem_size,
> +                              below_4g_mem_size + below_4g_hp_mem_size,
> +                              0x100000000ULL - below_4g_mem_size
> +                                - below_4g_hp_mem_size,
> +                              0x100000000ULL + above_4g_mem_size
> +                                + above_4g_hp_mem_size,
>                                (sizeof(target_phys_addr_t) == 4
>                                 ? 0
>                                 : ((uint64_t)1 << 62)),
> @@ -223,6 +229,8 @@ static void pc_init1(MemoryRegion *system_memory,
>          ioapic_init(gsi_state);
>      }
>
> +    main_memory_bus_create(object_resolve_path("i440fx", NULL));
> +
>      pc_register_ferr_irq(gsi[13]);
>
>      pc_vga_init(isa_bus, pci_enabled ? pci_bus : NULL);
> diff --git a/vl.c b/vl.c
> index af1745c..2282910 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -184,6 +184,7 @@ DisplayType display_type = DT_DEFAULT;
>  int display_remote = 0;
>  const char* keyboard_layout = NULL;
>  ram_addr_t ram_size;
> +ram_addr_t ram_hp_offset;
>  const char *mem_path = NULL;
>  #ifdef MAP_POPULATE
>  int mem_prealloc = 0; /* force preallocation of physical target memory */
> --
> 1.7.9
>
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