Re: [Xen-devel] Issues with latest staging tree starting PV guest.

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On 05/03/14 02:49, Mukesh Rathor wrote:
> On Mon, 3 Mar 2014 18:52:39 -0800
> Mukesh Rathor <mukesh.rathor@xxxxxxxxxx> wrote:
> 
>> Hi,
> ... 
>>   3. I setup xenbr, added vif line as always:
>>         vif = ['type=netfront,bridge=xenbr0']
>>
>>     But now get:
>>      libxl: error: libxl_create.c:1226:domcreate_attach_vtpms: unable
>>     to add nic devices
> 
> This is how far I got debugging this:
> 
> Looks like the issue is not getting domid, because stepping thru I see
> in devstate_watch_callback() it goes thru:
> 
>     } else {
>         int got = atoi(sstate);
>         if (got == ds->wanted) {
>             LIBXL__LOG(CTX, LIBXL__LOG_DEBUG, "backend %s wanted state %d ok",
>                        watch_path, ds->wanted);
>             rc = 0;
> logging:
> libxl: debug: libxl_event.c:653:devstate_watch_callback: backend 
> /local/domain/0/backend/vif/5/0/state wanted state 2 ok
> 
> then it calls:
> ...
> ds->callback(egc, ds, rc); --> device_backend_callback --> device_hotplug
> which does:
> ...
>     rc = libxl__get_domid(gc, &domid);  ---> libxl__xs_read_checked
>      --> libxl__xs_read (, , path="domid")...
>       This returns result == 0 and errno == ENOENT.
> 
> logging:
> libxl: debug: libxl_dm.c:1473:kill_device_model: Device Model signaled
> libxl: error: libxl_device.c:780:libxl__initiate_device_remove: unable to get 
> my domid
> 
> However, xenstore-ls, I see domid being there:
>   bash> xenstore-ls |grep domid
>      domid = "11"

What's missing is the domid from Dom0, not the domid of the guest. You
are missing an entry like:

/local/domain/0/domid = "0"

> 
> Zooming in libxl__xs_read, I got as far as :
> 
> libxl__xs_read -> xs_read((gc=0x636880, t=0x0, path=0x7ffff7bc13ba "domid")
>  --> .. --> xs_talkv() where:
> 
>         ret = read_reply(h, &msg.type, len);
>         if (!ret)
>                 goto fail;
> 
>         mutex_unlock(&h->request_mutex);
> 
>         sigaction(SIGPIPE, &oldact, NULL);
>         if (msg.type == XS_ERROR) {
>                 saved_errno = get_error(ret); <=========
> 
> Ian(s), any thoughts/ideas?

You need to update your init scripts, since commit
02ebea7768fe723deaa56c2cfcb860874544b47d Dom0 domid is written to
xenstore by xencommons init script, and libxl will fail to work properly
if the domid of Dom0 is not found.

Roger.


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