Re: [Qemu-devel] [4246] RAM usage information in machine definition.

["Blue Swirl" <blauwirbel@gmail.com>]

On 4/27/08, andrzej zaborowski <balrogg@gmail.com> wrote:
> On 26/04/2008, Igor Kovalenko <igor.v.kovalenko@gmail.com> wrote:
>  > On Sun, Apr 27, 2008 at 1:32 AM, andrzej zaborowski <balrogg@gmail.com> wrote:
>  >  >
>  >  > On 26/04/2008, Igor Kovalenko <igor.v.kovalenko@gmail.com> wrote:
>  >  >  > On Thu, Apr 24, 2008 at 9:59 PM, Andrzej Zaborowski <balrogg@gmail.com> wrote:
>  >  >  >  > Revision: 4246
>  >  >  >  >           http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=4246
>  >  >  >  >  Author:   balrog
>  >  >  >  >  Date:     2008-04-24 17:59:27 +0000 (Thu, 24 Apr 2008)
>  >  >  >  >
>  >  >  >  >  Log Message:
>  >  >  >  >  -----------
>  >  >  >  >  RAM usage information in machine definition.
>  >  >  >  [...]
>  >  >  >  >  Modified: trunk/hw/sun4u.c
>  >  >  >  >  ===================================================================
>  >  >  >  >  --- trunk/hw/sun4u.c    2008-04-24 17:20:25 UTC (rev 4245)
>  >  >  >  >  +++ trunk/hw/sun4u.c    2008-04-24 17:59:27 UTC (rev 4246)
>  >  >  >  >  @@ -385,4 +385,5 @@
>  >  >  >  >      "sun4u",
>  >  >  >  >      "Sun4u platform",
>  >  >  >  >      sun4u_init,
>  >  >  >  >  +    PROM_SIZE_MAX + VGA_RAM_SIZE,
>  >  >  >  >   };
>  >  >  >  >
>  >  >  >  [...]
>  >  >  >  >  Modified: trunk/vl.c
>  >  >  >  >  ===================================================================
>  >  >  >  >  --- trunk/vl.c  2008-04-24 17:20:25 UTC (rev 4245)
>  >  >  >  >  +++ trunk/vl.c  2008-04-24 17:59:27 UTC (rev 4246)
>  >  >  >  >  @@ -8277,7 +8277,7 @@
>  >  >  >  >      machine = first_machine;
>  >  >  >  >      cpu_model = NULL;
>  >  >  >  >      initrd_filename = NULL;
>  >  >  >  >  -    ram_size = DEFAULT_RAM_SIZE * 1024 * 1024;
>  >  >  >  >  +    ram_size = -1;
>  >  >  >  >      vga_ram_size = VGA_RAM_SIZE;
>  >  >  >  >   #ifdef CONFIG_GDBSTUB
>  >  >  >  >      use_gdbstub = 0;
>  >  >  >  >  @@ -8963,8 +8963,26 @@
>  >  >  >  >   #endif
>  >  >  >  >
>  >  >  >  >      /* init the memory */
>  >  >  >  >  -    phys_ram_size = ram_size + vga_ram_size + MAX_BIOS_SIZE;
>  >  >  >  >  +    phys_ram_size = machine->ram_require & ~RAMSIZE_FIXED;
>  >  >  >  >
>  >  >  >  >  +    if (machine->ram_require & RAMSIZE_FIXED) {
>  >  >  >  >  +        if (ram_size > 0) {
>  >  >  >  >  +            if (ram_size < phys_ram_size) {
>  >  >  >  >  +                fprintf(stderr, "Machine `%s' requires %i bytes of memory\n",
>  >  >  >  >  +                                machine->name, phys_ram_size);
>  >  >  >  >  +                exit(-1);
>  >  >  >  >  +            }
>  >  >  >  >  +
>  >  >  >  >  +            phys_ram_size = ram_size;
>  >  >  >  >  +        } else
>  >  >  >  >  +            ram_size = phys_ram_size;
>  >  >  >  >  +    } else {
>  >  >  >  >  +        if (ram_size < 0)
>  >  >  >  >  +            ram_size = DEFAULT_RAM_SIZE * 1024 * 1024;
>  >  >  >  >  +
>  >  >  >  >  +        phys_ram_size += ram_size;
>  >  >  >  >  +    }
>  >  >  >  >  +
>  >  >  >  >      phys_ram_base = qemu_vmalloc(phys_ram_size);
>  >  >  >  >      if (!phys_ram_base) {
>  >  >  >  >          fprintf(stderr, "Could not allocate physical memory\n");
>  >  >  >  >
>  >  >  >
>  >  >  >  512K is not enough to load sparc64 openbios ELF image
>  >  >  >  Can we do something to make sure the elf loader is aware of available space?
>  >  >  >  Or just restore old behavior:
>  >  >
>  >  >  The old behaviour shouldn't be changed as far as I can tell - only the
>  >  >  first PROM_SIZE_MAX bytes of the PROM were mapped to physical memory
>  >  >  even if it was larger.  If that's too little then yes, probably
>  >  >  PROM_SIZE_MAX was set too low, and yes the elf loader should know how
>  >  >  much space is available and not load images too big.
>  >  >
>  >
>  >
>  > Well, it was defined to 4M before r4246 in sysemu.h, see below.
>  >  Seems like for sun4u that was a typo, please apply the patch to
>  >  increase PROM_SIZE_MAX for sun4u.c
>
>
> That was MAX_BIOS_SIZE, but still only 512kB of the PROM was visible
>  in the guest.  So to restore the exact old behaviour would be to
>  increase the amount in sun4u_machine.ram_require but not touch
>  PROM_SIZE_MAX. I'm not sure what is more correct? Was it not a problem
>  before that part of the openbios ELF was effectively not loaded into
>  guest accessible ram?

Shouldn't be:
 $ objdump -h pc-bios/openbios-sparc64

pc-bios/openbios-sparc64:     file format elf64-sparc

Sections:
Idx Name          Size      VMA               LMA               File off  Algn
  0 .text         0002d188  00000000ffd00000  00000000ffd00000  00004000  2**14
                  CONTENTS, ALLOC, LOAD, CODE
  1 .rodata       000316b4  00000000ffd30000  00000000ffd30000  00034000  2**3
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  2 .data         000000e0  00000000ffd70000  00000000ffd70000  00074000  2**3
                  CONTENTS, ALLOC, LOAD, DATA
  3 .bss          00095000  00000000ffd71000  00000000ffd71000  000740e0  2**3
                  ALLOC

But increasing the limit to 4M in both sizes should be safer.