[OE-core] [PATCH] qemu*.conf: Add slirp support for all qemu machines

[Robert Yang]

On 11/30/2016 02:24 AM, Randy Witt wrote:
>
>>
>> "-device virtio-net-device,netdev=net0" and
>> "-netdev user,id=net0,hostfwd=tcp::2222-:22"
>>
>> Then there is no way for user to override the second part, and we can't
>> call the first part as a "QB_SLIRP_OPT" since it is only part of them,
>> so I won't break them into 2, and if the user defines QB_SLIRP_OPT
>> in there bsp conf file, then it will be replaced totally.
>>
>
> I'm aware that this will only work for one instance, but currently it doesn't
> work at all and it blocks a high priority bug. The only way to make it 100%
> work, would be to have qemu do the binding of the port to a dynamic one and then
> the user queries it after. Otherwise there is always a window where another
> process could bind to the port.

We can check whether the port is free and use another one if not, we've
already done similar things in runqemu-export-rootfs for nfs, please see:

http://lists.openembedded.org/pipermail/openembedded-core/2016-November/129376.html

// Robert

>
> I don't think the bsp should be in the business of choosing which ports to
> forward. And if it is, then it should be a separate option in the qemuboot.conf,
> with just the "-netdev user" part because otherwise the user will always have to
> modify qemuboot.conf just to forward different ports.
>
> It makes more sense to let the user do something like "runqemu slirp=22,65,..."
> and then return back the actual port used in the forwarding.


>
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