Re: [PATCH 5/5] x86/xen: Don't register PV spinlock IPI when it isn't going to be used

[boris.ostrovsky@xxxxxxxxxx]

On 1/4/21 12:32 PM, David Woodhouse wrote:
> On Mon, 2021-01-04 at 12:06 -0500, boris.ostrovsky@xxxxxxxxxx wrote:
>>> @@ -115,7 +115,7 @@ PV_CALLEE_SAVE_REGS_THUNK(xen_vcpu_stolen);
>>>   void __init xen_init_spinlocks(void)
>>>   {
>>>        /*  Don't need to use pvqspinlock code if there is only 1 vCPU. */
>>> -     if (num_possible_cpus() == 1 || nopvspin)
>>> +     if (num_possible_cpus() == 1 || nopvspin || !xen_have_vector_callback)
>>
>> xen_init_spinlock() will not be called without vector callbacks so
>> this test is not really necessary.
> Right, that's just paranoia to make the conditions consistent and safe.


OK, but we still need to do something about virt_spin_lock_key.


-boris