[yocto] [PATCH 1/1] runqemu: add user mode (SLIRP) support to x86 QEMU targets

[Mark Hatle]

On 10/24/16 6:46 PM, Todor Minchev wrote:
> On Mon, 2016-10-24 at 18:15 -0500, Mark Hatle wrote:
>> On 10/24/16 5:19 PM, Todor Minchev wrote:
>>> Using 'slirp' as a command line option to runqemu will start QEMU
>>> with user mode networking instead of creating tun/tap devices.
>>> SLIRP does not require root access. By default port 2222 on the
>>> host will be mapped to port 22 in the guest. The default port
>>> mapping can be overwritten with the QB_SLIRP_OPT variable e.g.
>>>
>>> QB_SLIRP_OPT = "-net nic,model=e1000 -net user,hostfwd=tcp::2222-:22"
>>
>> In the past patches like this have been rejected for performance and other
>> reasons.  
> 
> Performance is not ideal with SLIRP, but should be sufficient for basic
> ssh access to the guest. Could you please elaborate on the other reasons
> why having this is a bad idea?

You'd have to go back in the archives.  Performance was the main reason I
remember being discussed at the time.

I don't remember the others, and as I said, I'm not a fan of requiring root, but
the community decided sudo approach was better as long as there was a way to
avoid it.

Changing the default will likely require email to the oe-core list and/or
oe-architecture list...

>> While I don't particularly like requiring sudo access for runqemu,
>> adding the 'slirp' option will allow someone w/o root/sudo to be able to run it.
> 
> The goal was to be able to run a QEMU image and provide basic networking
> without requiring root access. Is there any reason why running runqemu
> w/o root/sudo access should be discouraged?   

As long as you can pass in slirp (and it's not the default) then I believe your
requirement and the community direction is preserved.

>> Otherwise, if there is something you can do to make slirp work better (when
>> enabled), that is more likely to be accepted.
> 
> Similar SLIRP support has been already accepted for qemuarm64 with
> commit 9b0a94cb

Support for slirp is good, it's defaulting to slirp that has been rejected in
the past by the community.

> --Todor
> 
> Intel Open Source Technology Center
> 
>> --Mark
>>
>>> Signed-off-by: Todor Minchev <todor.minchev at linux.intel.com>
>>> ---
>>>  meta/conf/machine/include/qemuboot-x86.inc | 1 +
>>>  scripts/runqemu                            | 3 ++-
>>>  2 files changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/meta/conf/machine/include/qemuboot-x86.inc b/meta/conf/machine/include/qemuboot-x86.inc
>>> index 06ac983..0870294 100644
>>> --- a/meta/conf/machine/include/qemuboot-x86.inc
>>> +++ b/meta/conf/machine/include/qemuboot-x86.inc
>>> @@ -13,3 +13,4 @@ QB_AUDIO_OPT = "-soundhw ac97,es1370"
>>>  QB_KERNEL_CMDLINE_APPEND = "vga=0 uvesafb.mode_option=640x480-32 oprofile.timer=1 uvesafb.task_timeout=-1"
>>>  # Add the 'virtio-rng-pci' device otherwise the guest may run out of entropy
>>>  QB_OPT_APPEND = "-vga vmware -show-cursor -usb -usbdevice tablet -device virtio-rng-pci"
>>> +QB_SLIRP_OPT = "-net nic,model=e1000 -net user,hostfwd=tcp::2222-:22"
>>> diff --git a/scripts/runqemu b/scripts/runqemu
>>> index dbe17ab..6952f32 100755
>>> --- a/scripts/runqemu
>>> +++ b/scripts/runqemu
>>> @@ -542,7 +542,8 @@ class BaseConfig(object):
>>>      def check_and_set(self):
>>>          """Check configs sanity and set when needed"""
>>>          self.validate_paths()
>>> -        check_tun()
>>> +        if not self.slirp_enabled:
>>> +            check_tun()
>>>          # Check audio
>>>          if self.audio_enabled:
>>>              if not self.get('QB_AUDIO_DRV'):
>>>
>>
> 
>