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From:   "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
To:     Vitaly Kuznetsov <vkuznets@redhat.com>,
        "mhkelley58@gmail.com" <mhkelley58@gmail.com>
CC:     "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
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        "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        KY Srinivasan <kys@microsoft.com>
Subject: RE: [PATCH char-misc 1/1] Drivers: hv: vmbus: Make synic_initialized
 flag per-cpu
Thread-Topic: [PATCH char-misc 1/1] Drivers: hv: vmbus: Make synic_initialized
 flag per-cpu
Thread-Index: AQHUKHxDlEyTLKiml0qH4U3EvoNZ3KSpL9oigAEw2VA=
Date:   Wed, 1 Aug 2018 05:47:08 +0000
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From: Vitaly Kuznetsov <vkuznets@redhat.com> Sent: Tuesday, July 31, 2018 4=
:20 AM
>=20
> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>

Thanks for the review

>=20
> 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:
>=20
> int hv_synic_is_initialized(void) {
> 	union hv_synic_scontrol sctrl;
>=20
> 	hv_get_synic_state(sctrl.as_uint64);
>=20
> 	return sctrl.enable;
> }
>=20
> as it doesn't seem that we need to check synic state on _other_ CPUs.
>=20
> --
>   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