Re: [Xen-devel] dom0less + sched=null => broken in staging

[Julien Grall <julien.grall@arm.com>]

Hi Dario,

On 8/13/19 4:27 PM, Dario Faggioli wrote:
> On Fri, 2019-08-09 at 11:30 -0700, Stefano Stabellini wrote:
>> On Fri, 9 Aug 2019, Dario Faggioli wrote:
>>> Can you help me with this, e.g., by providing some more info and,
>>> if
>>> possible, logs?
>>
>> I am attaching the logs.
>>
> Thanks!
> 
>> Interestingly, I get a bunch of:
>>
>> (XEN) *** LOADING DOMU cpus=1 memory=40000KB ***
>> (XEN) sched_null.c:458: Not inserting d2v0 (not online!)
>>
>> Maybe we are missing a call to online the vcpus somewhere in
>> xen/arch/arm/domain_build.c:construct_domain?
>>
> Actually, those lines are normal, because vCPUs are created offline.
> (see the set_bit(_VPF_down) in vcpu_create()).
> 
> The problem is why aren't they coming up. Basically, you're missing a
> call to vcpu_wake().
> 
> In my (x86 and "dom0full") testbox, this seems to come from
> domain_unpause_by_systemcontroller(dom0) called by
> xen/arch/x86/setup.c:init_done(), at the very end of __start_xen().
> 
> I don't know if domain construction in an ARM dom0less system works
> similarly, though. What we want, is someone calling either vcpu_wake()
> or vcpu_unpause(), after having cleared _VPF_down from pause_flags.

Looking at create_domUs() there is a call to 
domain_unpause_by_controller for each domUs.

Cheers,

-- 
Julien Grall

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