[Qemu-devel] Re : [SeaBIOS] : Memory problem with Qemu/SeaBIOS

["Alain Ribière" <alain_ribiere@yahoo.com>]

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Thanks for your answer.


Here is the debug log in attachement.
I disabled the debug on the screen shot I sent because I noticed I could get a bit more memory without it.
With the debug on, I got :
Banked Window  416K at 3800:0 segment
and a free memory of 15680K

I'll try to find what confuses C-DOS. It reacts a bit strangely... 
When I add or remove options from the SeaBIOS, the memory avalaible 
change and the size of banked window changes too. So I hoped there was a way to have enough memory to run my application...
Otherwise, I will have to stuck with Qemu 0.11 and PC-BIOS.

Do you know if there is any DOS utility to get the memory map ?

Thanks,

Alain 

________________________________
On Mon, May 07, 2012 at 08:58:45AM -0700, Alain Ribière wrote:
> Hello,
> 
> I have a memory trouble with an old DOS OS from Digital Research
 called Concurrent DOS.
> It worked fine till Qemu v0.11.1.
> I
 use Qemu to make a legacy application run without any modification.
> 
> Starting with Qemu 0.12, my legacy application has not enough memory to run.
> Actually it seems that the SeaBIOS doesn't use the same memory mapping than PC-BIOS used to, causing trouble to my application.
> 
> Is there any way to get SeaBIOS use (more or less) the same memory amount and memory mapping than the older PC-BIOS ?
> 
> I tried to recomplie SeaBIOS 1.7.0 with less options but the result is the same.

When reporting an issue with SeaBIOS, please include the log obtained
when running qemu with "-chardev stdio,id=seabios -device
isa-debugcon,iobase=0x402,chardev=seabios".

I took a quick look at this, and I don't think this is a memory size
issue - the screenshots actually show that running under seabios makes
more memory available (15664 vs 15648).  Instead, I'd guess concurrent
dos is not making a
 "banked window" that is large enough.  I don't
know why the memory segments between 0x0b00 and 0x3400 aren't being
used.  There is no legacy bios interface to reserve memory under 1meg,
so I'm sure SeaBIOS isn't doing this wrong.  Indeed, SeaBIOS is much
more careful about touching ram under 1meg than Bochs bios is.

So, I'd guess something unrelated is confusing concurrent dos and the
above is just a symptom of the problem.  Unfortunately, I don't know
of any way to track that down without source code for the image and
spending a large amount of debugging time.

-Kevin

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Start bios (version 1.7.0-20120508_175951-viper)
Ram Size=0x01000000 (0x0000000000000000 high)
Relocating init from 0x000f3790 to 0x00feb6c0 (size 18460)
CPU Mhz=2568
=== PCI bus & bridge init ===
PCI: pci_bios_init_bus_rec bus = 0x0
=== PCI device probing ===
Found 6 PCI devices (max PCI bus is 00)
=== PCI new allocation pass #1 ===
PCI: check devices
=== PCI new allocation pass #2 ===
PCI: init bases bus 0 (primary)
  type io max 40 sum 50 base c000
    size       40: 1 bar(s),     c000 ->     c03f
    size       10: 1 bar(s),     c040 ->     c04f
  type mem max 20000 sum 31000 base febc0000
    size    20000: 1 bar(s), febc0000 -> febdffff
    size    10000: 1 bar(s), febe0000 -> febeffff
    size     1000: 1 bar(s), febf0000 -> febf0fff
  type prefmem max 2000000 sum 2000000 base fc000000
    size  2000000: 1 bar(s), fc000000 -> fdffffff
PCI: map device bdf=00:00.0
PCI: map device bdf=00:01.0
PCI: map device bdf=00:01.1
  bar 4, addr c040, size 10 [io]
PCI: map device bdf=00:01.3
PCI: map device bdf=00:02.0
  bar 0, addr fc000000, size 2000000 [prefmem]
  bar 1, addr febf0000, size 1000 [mem]
  bar 6, addr febe0000, size 10000 [mem]
PCI: map device bdf=00:03.0
  bar 0, addr febc0000, size 20000 [mem]
  bar 1, addr c000, size 40 [io]
PCI: init bdf=00:00.0 id=8086:1237
PCI: init bdf=00:01.0 id=8086:7000
PCI: init bdf=00:01.1 id=8086:7010
PCI: init bdf=00:01.3 id=8086:7113
PCI: init bdf=00:02.0 id=1013:00b8
PCI: init bdf=00:03.0 id=8086:100e
PIIX3/PIIX4 init: elcr=00 0c
Found 1 cpu(s) max supported 1 cpu(s)
Scan for VGA option rom
Running option rom at c000:0003
Turning on vga text mode console
SeaBIOS (version 1.7.0-20120508_175951-viper)

PS2 keyboard initialized
Found 1 lpt ports
Found 1 serial ports
ATA controller 1 at 1f0/3f4/0 (irq 14 dev 9)
ATA controller 2 at 170/374/0 (irq 15 dev 9)
DVD/CD [ata1-0: QEMU DVD-ROM ATAPI-4 DVD/CD]
Scan for option roms
Returned 65536 bytes of ZoneHigh
e820 map has 5 items:
  0: 0000000000000000 - 000000000009fc00 = 1 RAM
  1: 000000000009fc00 - 00000000000a0000 = 2 RESERVED
  2: 00000000000f0000 - 0000000000100000 = 2 RESERVED
  3: 0000000000100000 - 0000000001000000 = 1 RAM
  4: 00000000fffc0000 - 0000000100000000 = 2 RESERVED
enter handle_19:
  NULL
Booting from Floppy...
Booting from 0000:7c00

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