From: Scott Wood <scottwood@freescale.com>
To: Alexander Graf <agraf@suse.de>
Cc: Liu Yu <yu.liu@freescale.com>,
"<kvm-ppc@vger.kernel.org>" <kvm-ppc@vger.kernel.org>,
"<kvm@vger.kernel.org>" <kvm@vger.kernel.org>,
"<linuxppc-dev@ozlabs.org>" <linuxppc-dev@ozlabs.org>,
"<B07421@freescale.com>" <B07421@freescale.com>
Subject: Re: [PATCH v4 3/3] KVM: PPC: epapr: install ev_idle hcall for e500 guest
Date: Thu, 16 Feb 2012 11:36:09 -0600 [thread overview]
Message-ID: <4F3D3E89.3050301@freescale.com> (raw)
In-Reply-To: <144AF998-6DEE-453A-872A-B148ACA2B7B8@suse.de>
On 02/16/2012 11:30 AM, Alexander Graf wrote:
>
> On 16.02.2012, at 18:28, Scott Wood wrote:
>
>> On 02/16/2012 11:18 AM, Alexander Graf wrote:
>>> Hrm. But we can clobber ctr, right? So how about we make the generic version do a bctr and then just do a small C wrapper that takes lr, moves it to ctr and branches to the generic one?
>>
>> If it's just for this, I would say don't mess with the normal hcall path
>> for the sake of idle. If using CTR would let us get away without
>> creating a stack frame in call sites, maybe that would be worthwhile,
>> depending on what sort of hcalls we end up having.
>>
>>> Then we don't have to replicate the hypercall code all over again for every invocation.
>>
>> We shouldn't need to do it for every invocation. Idle is special due to
>> the TLF_NAPPING hack.
>
> Famous last words. If it's the only case, duplication should be ok. Let's hope there are no others.
Actually, we can't use CTR -- it's volatile in the ePAPR hypercall ABI.
-Scott
next prev parent reply other threads:[~2012-02-16 17:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-16 9:26 [PATCH v4 1/3] KVM: PPC: epapr: Factor out the epapr init Liu Yu
2012-02-16 9:26 ` [PATCH v4 2/3] KVM: PPC: epapr: Add idle hcall support for host Liu Yu
2012-02-16 9:26 ` [PATCH v4 3/3] KVM: PPC: epapr: install ev_idle hcall for e500 guest Liu Yu
2012-02-16 10:24 ` Alexander Graf
2012-02-16 16:58 ` Scott Wood
2012-02-16 17:18 ` Alexander Graf
2012-02-16 17:28 ` Scott Wood
2012-02-16 17:30 ` Alexander Graf
2012-02-16 17:36 ` Scott Wood [this message]
2012-02-16 17:39 ` Alexander Graf
2012-02-16 17:14 ` Scott Wood
2012-02-16 10:20 ` [PATCH v4 2/3] KVM: PPC: epapr: Add idle hcall support for host Alexander Graf
2012-02-17 2:13 ` Liu Yu-B13201
2012-02-17 2:20 ` Alexander Graf
2012-02-16 10:17 ` [PATCH v4 1/3] KVM: PPC: epapr: Factor out the epapr init Alexander Graf
2012-02-16 17:13 ` Scott Wood
2012-02-17 10:03 ` Liu Yu-B13201
2012-02-17 18:58 ` Scott Wood
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