netdemo on qemu (i386) [was Re: GNATS-1110: in_cksum_hdr error in PC386 BSP]

Till Straumann strauman at
Wed Jun 28 18:17:51 UTC 2006

Eric Norum wrote:

> On Jun 28, 2006, at 11:44 AM, Till Straumann wrote:
>> Weird - I very recently (1week ago) tested
>> networking in qemu (i386 target, i386-linux host)
>> and I didn't notice anything unusual.
>> I'm still using gcc-4.0.2 (rtems CVS head).
> So why has Joel been pestering us to fix qemu?

I don't know. Just downloaded 'netdemo' (before, I
had tested our own application). Seems to work fine.

rtems: CVS head as of some time last week
gcc:     4.0.2 [maybe a newer compiler exposes the GNATS-1110 problem?]
host:   i386-linux
target:  i386-rtems (pc586 BSP)
qemu:  0.8.1,  i386-softmmu target
netdemo config:   'ne' (ISA) driver ("ne1" / rtems_ne_attach)

I build a bootable cd image (grub), start netdemo and
it seems to work fine (telnetting to port 24742 on localhost
connects me to netdemo; can print stats on console).

CAVEATS: qemu uses interrupt 9, rtems' driver by default uses
interrupt 5 -> the netdriver configuration table needs a

irno: 9


Also, in order for qemu's bootp server to recognize the emulated
system the ethernet address must not be set by the application
(but use emulated hw-default).

Here's my qemu command line (didn't bother to install it)

i386-softmmu/qemu -L ../pc-bios -net nic,model=ne2k_isa -net user -cdrom 
tst.iso -redir tcp:24742::24742

-- Till

> -- 
> Eric Norum <norume at <mailto:norume at>>
> Advanced Photon Source
> Argonne National Laboratory
> (630) 252-4793

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