Re: [Qemu-discuss] [BUG or NOT] NICs in up state can not receive any packages if other one NIC is in down state

[Rongqing Li]

On 2012年08月17日 16:06, Stefan Hajnoczi wrote:
> On Fri, Aug 17, 2012 at 09:38:45AM +0800, Rongqing Li wrote:
> > On 2012年08月16日 20:57, Stefan Hajnoczi wrote:
> > > I think the solution is not to drop Vincent/Zhi Yong's code.  Instead we
> > > should distinguish between "up" and "down".  If a net client is "up" but
> > > cannot receive, then the hub will queue the packet.  If a net client is
> > > "down" then the hub will ignore the client and send packets to other
> > > clients.
> > >
> > > I don't have patches for this but have added it to my TODO list.
> > >
> > > Stefan
> >
> > Ok, Thanks for you explanation! and expect your patch.
>
> If you have time to fix this I suggest you try to submit the patch
> because I may not get to within the next week.
>
> We need a way to determine whether the interface is up/down.  There is
> already a link_down flag that can be set.  Not sure if its semantics are
> exactly what we need, you'd need to check net.h/net.c.
>
> The second step is looking at qemu_can_send_packet() and .can_receive().
> net/hub.c:net_hub_port_can_receive() needs to be tweaked so peers with
> link_down are skipped.
>
> Stefan
Hi Stefan:

Seem the link_down flags can not report if NIC is in down or in
up status.

Down the NIC by "ifconfig eth0 down", but link_down still is 0,
and "mii-tool eth0" says link is ready.

To e1000 dev, only "s->mac_reg[RCTL] & E1000_RCTL_EN" is 0 after
down it.

I did not find other flags and methods which reflect the NIC
up/down status.


-Roy
>

--
Best Reagrds,
Roy | RongQing Li