Date: Sat, 9 May 2015 09:51:01 +0200
From: Thomas Huth <thuth@redhat.com>
Message-ID: <20150509095101.468c85e1@thh440s>
In-Reply-To: <554CCAB5.3030000@redhat.com>
References: <1431077765-6461-1-git-send-email-thuth@redhat.com>
	<554CCAB5.3030000@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] net: Change help text to list -netdev
 instead of -net by default
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>, "Michael S.
	Tsirkin" <mst@redhat.com>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>, Markus Armbruster <armbru@redhat.com>

On Fri, 08 May 2015 16:39:49 +0200
Paolo Bonzini <pbonzini@redhat.com> wrote:

> 
> 
> On 08/05/2015 11:36, Thomas Huth wrote:
> > Looking at the output of "qemu-system-xxx -help", you easily get
> > the impression that "-net" is the preferred way instead of "-netdev"
> > to specify host network interface, since the "-net" option is
> > omnipresent but the "-netdev" option is only listed as a one-liner
> > at the end. This is ugly since "-net" is considered as legacy and
> > even might be removed one day. Thus, this patch switches the output
> > to explain the host network interfaces with the "-netdev" option
> > instead, moving the legacy "-net" option into some few lines at
> > the end.
> > 
> > Signed-off-by: Thomas Huth <thuth@redhat.com>
> > ---
> >  qemu-options.hx | 66 ++++++++++++++++++++++++++++++++++-----------------------
> >  1 file changed, 39 insertions(+), 27 deletions(-)
> 
> That would be great if it worked for all machine types, but it doesn't.
>  For example, there's no equivalent of:
> 
> $ qemu-system-arm -net user -net nic -machine versatilepb
> 
> You cannot just use -netdev:
> 
> $ qemu-system-arm -netdev user,id=nd0 -machine versatilepb
> Warning: netdev nd0 has no peer
> 
> You cannot use -netdev and -net together:
> 
> $ qemu-system-arm -netdev user,id=nd0 -net nic -machine versatilepb
> Warning: vlan 0 is not connected to host network
> Warning: netdev nd0 has no peer
> 
> This particular board has a PCI controller, so you can just add a PCI
> NIC using -netdev/-device, but still that wouldn't be a match for "-net
> user -net nic" (which puts a smc91c111 NIC on sysbus).  In most embedded
> boards there's not even a PCI controller.
> 
> So the patch is great, but I wouldn't say it's deprecated, because in
> practice it isn't.

Ok, makes sense, I'll remove the "deprecated" wording.

 Thomas