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

[Todor Minchev <todor.minchev@linux.intel.com>]

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?

> 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?   

> 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

--Todor

Intel Open Source Technology Center

> --Mark
> 
> > Signed-off-by: Todor Minchev <todor.minchev@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'):
> > 
>