Re: [Qemu-devel] What should a virtual board emulate?

[Philippe Mathieu-Daudé]

Hi Paolo,

On 3/20/19 11:35 AM, Paolo Bonzini wrote:
> On 20/03/19 11:03, Philippe Mathieu-Daudé wrote:
> > -display/-vga options suffers same clarity problems than -net. Is it a
> > card device or a cable linking to a network? Here is it a card device or
> > a cable connecting a monitor display?
>
> -display is a cable, -vga is a card ("-nic none" is a card, "-nic
> anythingelse" is a card+cable; "-net nic" is a card, "-net anythingelse"
> is a cable).
>
> >      Mind, I'm not demanding mips-fulong2e should continue to ignore -vga;
> >      that's for its maintainer to decide.  I don't demand, I ask: what should
> >      a virtual board emulate?  What should -nodefaults do?
> >
> > IMHO -nodefaults contains soldered/mmio chipsets.
> > Whether you plug a display or not is a different story.
>
> In principle you could also cut the copper tracks that connect the card
> to the PCI bus...

But then you have a crippled machine... We are not trying to model that.

I went back to continue a Fuloong Avocado test I started a year ago, and 
it was failing. I remember I had something working, so I bisected and 
reached this commit...

78c37d88f1b8b0b3ebcc632c458f0c3779fe2951 is the first bad commit
commit 78c37d88f1b8b0b3ebcc632c458f0c3779fe2951
Author: Paolo Bonzini <address@hidden>
Date:   Tue Mar 19 15:37:19 2019 +0100

    mips-fulong2e: obey -vga none

    Do not create an ATI VGA if "-vga none" was passed on the command line.

Booting PMON 1.1.2:

console: PMON2000 MIPS Initializing. Standby...
console: ERRORPC=00000000 CONFIG=00030932
console: PRID=00006302
console: DIMM read
console: 00000080
console: read memory type
console: read number of rows
console: read memory size per side
console: read blocks per ddrram
console: read number of sides
console: read width
console: DIMM SIZE=10000000
console: sdcfg=3d5043df
console: msize=10000000
console: Init SDRAM Done!
console: Sizing caches...
console: Init caches...
console: godson2 caches found
console: Init caches done, cfg = 00030932
console: Copy PMON to execute location...
console: start = 0x85000000
console: s0 = 0x3ac00000
console: a5000000
console: a5010000
console: a5020000
console: a5030000
console: a5040000
console: copy text section done.
console: Copy PMON to execute location done.
console: sp=84ffc000Uncompressing Bios........................OK,Booting 
Bios
console: FREQ
console: FREI
console: DONE
console: TTYI
console: TTYD
console: ENVI
console: MAPV
console: Mfg  0, Id 60
console: STDV
console: 80100000: heap is already above this point
console: SBDD
console: 686I
console: 0x3f8=ff
console: PPCIH
console: PCI bus 0 slot 5/0: reg 0x10 = 0x0
console: PCI bus 0 slot 5/0: reg 0x14 = 0x0
console: PCI bus 0 slot 5/0: reg 0x18 = 0x0
console: PCI bus 0 slot 5/0: reg 0x1c = 0x0
console: PCI bus 0 slot 5/0: reg 0x20 = 0x0
console: PCI bus 0 slot 5/0: reg 0x24 = 0x0
console: PCI bus 0 slot 5/1: reg 0x10 = 0xfffffff9
console: PCI bus 0 slot 5/1: reg 0x14 = 0xfffffffd
console: PCI bus 0 slot 5/1: reg 0x18 = 0xfffffff9
console: PCI bus 0 slot 5/1: reg 0x1c = 0xfffffffd
console: PCI bus 0 slot 5/1: reg 0x20 = 0xfffffff1
console: PCI bus 0 slot 5/1: reg 0x24 = 0x0
console: PCI bus 0 slot 5/2: reg 0x10 = 0x0
console: PCI bus 0 slot 5/2: reg 0x14 = 0x0
console: PCI bus 0 slot 5/2: reg 0x18 = 0x0
console: PCI bus 0 slot 5/2: reg 0x1c = 0x0
console: PCI bus 0 slot 5/2: reg 0x20 = 0xffffffe1
console: PCI bus 0 slot 5/2: reg 0x24 = 0x0
console: PCI bus 0 slot 5/3: reg 0x10 = 0x0
console: PCI bus 0 slot 5/3: reg 0x14 = 0x0
console: PCI bus 0 slot 5/3: reg 0x18 = 0x0
console: PCI bus 0 slot 5/3: reg 0x1c = 0x0
console: PCI bus 0 slot 5/3: reg 0x20 = 0xffffffe1
console: PCI bus 0 slot 5/3: reg 0x24 = 0x0
console: PCI bus 0 slot 5/4: reg 0x10 = 0x0
console: PCI bus 0 slot 5/4: reg 0x14 = 0x0
console: PCI bus 0 slot 5/4: reg 0x18 = 0x0
console: PCI bus 0 slot 5/4: reg 0x1c = 0x0
console: PCI bus 0 slot 5/4: reg 0x20 = 0x0
console: PCI bus 0 slot 5/4: reg 0x24 = 0x0
console: PCI bus 0 slot 5/5: reg 0x10 = 0x0
console: PCI bus 0 slot 5/5: reg 0x14 = 0x0
console: PCI bus 0 slot 5/5: reg 0x18 = 0x0
console: PCI bus 0 slot 5/5: reg 0x1c = 0x0
console: PCI bus 0 slot 5/5: reg 0x20 = 0x0
console: PCI bus 0 slot 5/5: reg 0x24 = 0x0
console: PCI bus 0 slot 5/6: reg 0x10 = 0x0
console: PCI bus 0 slot 5/6: reg 0x14 = 0x0
console: PCI bus 0 slot 5/6: reg 0x18 = 0x0
console: PCI bus 0 slot 5/6: reg 0x1c = 0x0
console: PCI bus 0 slot 5/6: reg 0x20 = 0x0
console: PCI bus 0 slot 5/6: reg 0x24 = 0x0
console: PCIS
console: PCIR
console: PCIW
console: NETI
console: RTCL
console: PCID
console: VGAI
console: Default MODE_ID 2
console: starting radeon init...
^
Current QEMU is stuck here.

Before it would continue:

console: iobase=bfd0a100,mmbase=b5050000
console: mc_status=5
console: mc_status=5
console: mc_status=5
console: mc_status=5
console: ppll_div_3 = 301f4
console: Wrote: 0x00000043 0x000301f4 0x00000000 (0x00000000)
console: Wrote: rd=67, fd=500, pd=3
console: VCLK_ECP_CNTL = 000000C3
console: radeon init done
console: FRBI
console: cfb_console init,fb=b4000000
console: Video: Drawing the logo ...
console: CONSOLE_SIZE 450560HSTI
...

Since:

1/ the Radeon chip is soldered on the motherboard,

2/ the default BIOS expects the Radeon chip to be
   unconditionally present,

I insist this patch is incorrect for the particular case of the 
Fuloong2e board. I plan to revert it when I post the test.

BTW I'm not using --nodefault, I'm running default ./configure:

qemu-system-mips64el -M fulong2e -bios pmon_2e.bin \
-display none -vga none -serial stdio

Regards,

Phil.