Re: [Qemu-devel] Networking hangs

[Christoffer Dall <cdall@vmware.com>]

Hi there.

I tried to verify if the bug existed with Realview, but I just can't get 
the guest to mount an sd-card, which I created with qemu-img and copied 
a roots onto there and the guest kernel cannot be configured with 
PCI/SCSI support for the ext2 image.

Do you have any ideas on how to proceed with either the realview stuff 
to see if that's the problem or with the networking issue?

Thanks!

Best,
Christoffer

Scott Tsai wrote:
> On Sat, Nov 21, 2009 at 7:29 AM, Aurelien Jarno <aurelien@aurel32.net> wrote:
>> On Thu, Nov 19, 2009 at 05:48:02PM -0500, Christoffer Dall wrote:
>>> Hi.
>>>
>>> I am experiencing problems with bridged networking to ARM guests. I have
>>> experimented with various kernel versions, distributions and host
>>> machines and I experience the problem in all cases.
>>>
>>> When I copy files into the guest using SCP, after an undeterministic
>>> number of megabytes have been copied, the network crashes. At this point
>>> not even pings to localhost works inside the guest.
>>>
>>> I am using v0.11.0, emulating a versatilepb board with an arm1136-r2 cpu
>> Have you tried to use the stable-0.11 branch (that will become 0.11.1 at
>> some point) instead? It has some ARM and network related fixes.
> 
> Using the files that Christoffer uploaded, I can reproduce this bug
> even on stable-0.11.
> (i.e. using scp to copy a large file seems to "hang" the network stack
> in the guest to the point that even "ping 127.0.0.1" fails)
> 
> The interesting part about this bug is that Christoffer patched the
> Linux kernel to allow using an ARMv6 CPU on the versatilepb board.
> I've verified that by changing the emulated cpu from arm1136-r2 to
> arm926 and building a kernel for the arm926 this bug no longer
> happens.
> 
> I'm not familiar enough with the ARM architecture to explain why the
> versatilepb board would have such "reliability problems" with
> arm1136-r2 CPU right away.
> I was about to try emulating a arm1136-r2 CPU on a realview board.