RE: [PATCH char-misc 1/1] Drivers: hv: vmbus: Make synic_initialized flag per-cpu

[Michael Kelley (EOSG)]

From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Sent: Tuesday, July 31, 2018 4:20 AM
> 
> Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>

Thanks for the review

> 
> Alternatively, we can get rid of synic_initialized flag altogether:
> hv_synic_init() never fails in the first place but we can always
> implement something like:
> 
> int hv_synic_is_initialized(void) {
> 	union hv_synic_scontrol sctrl;
> 
> 	hv_get_synic_state(sctrl.as_uint64);
> 
> 	return sctrl.enable;
> }
> 
> as it doesn't seem that we need to check synic state on _other_ CPUs.
> 
> --
>   Vitaly

I was trying to decide if there are any arguments in favor of one
approach vs. the other:  a per-cpu flag in memory or checking
the synic_control "enable" bit.   Seems like a wash to me, in which
case I have a slight preference for the per-cpu flag in memory vs.
creating another function to return sctrl.enable.  But I'm completely
open to reasons why checking sctrl.enable is better.

Michael