From: Scott Wood <scottwood@freescale.com>
To: kvm-ppc@vger.kernel.org
Subject: Re: [PATCH 4/5] KVM: PPC: e500: eliminate a trap when entering idle
Date: Thu, 15 Sep 2011 21:36:16 +0000 [thread overview]
Message-ID: <4E726FD0.5080905@freescale.com> (raw)
In-Reply-To: <20110826233144.GD30607@schlenkerla.am.freescale.net>
On 09/05/2011 05:30 PM, Alexander Graf wrote:
>
> On 27.08.2011, at 01:31, Scott Wood wrote:
>
>> +#ifdef CONFIG_E500
>> + /*
>> + * Skip the overhead of HID0 accesses that KVM ignores --
>> + * just write MSR[WE].
>> + *
>> + * We don't need _TLF_NAPPING, because under KVM we know
>> + * it will take effect right away.
>> + */
>> + if (ppc_md.power_save = e500_idle)
>> + ppc_md.power_save = kvm_msrwe_idle;
>
> Why the if() here?
To avoid replacing some other power_save() implementation.
kvm_msrwe_idle() is a paravirt-optimized version of e500_idle().
However, now that e500_idle has an ifdef for e500mc, we'll need that
ifdef here as well. e500mc doesn't use MSR[WE] (and if it did, we
couldn't trap on it). For e500mc we'll want to make an hcall for idle
(ePAPR EV_IDLE).
-Scott
next prev parent reply other threads:[~2011-09-15 21:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-26 23:31 [PATCH 4/5] KVM: PPC: e500: eliminate a trap when entering idle Scott Wood
2011-09-05 22:30 ` Alexander Graf
2011-09-15 21:36 ` Scott Wood [this message]
2011-09-19 9:33 ` Alexander Graf
2011-09-19 18:46 ` Scott Wood
2011-09-19 18:50 ` Alexander Graf
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