From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerone Young Date: Fri, 28 Mar 2008 21:55:04 +0000 Subject: Re: [kvm-ppc-devel] [PATCH 1 of 2] Add MSR Wait state to Message-Id: <1206741304.22572.6.camel@thinkpadL> List-Id: References: <1206740585.5432.29.camel@basalt> In-Reply-To: <1206740585.5432.29.camel@basalt> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-ppc@vger.kernel.org On Fri, 2008-03-28 at 16:43 -0500, Hollis Blanchard wrote: > On Fri, 2008-03-28 at 16:34 -0500, Jerone Young wrote: > > # HG changeset patch > > # User Jerone Young > > # Date 1206720510 18000 > > # Node ID e48cf2ad6c85c457ff64c04b83960fc305420842 > > # Parent 1506aa38ddabb0bf73fff3ac3f3db5f9ef6458cc > > Add MSR Wait state to cpu_idle loop > > > > This patch sets the wait state MSR when in the cpu_idle loop. This is > > mainly to help out virtualization solutions such as KVM. This way the > > virtualization soultion is able to tell if the guest kernel is idle. > > > > Signed-off-by: Jerone Young > > > > diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c > > --- a/arch/powerpc/kernel/idle.c > > +++ b/arch/powerpc/kernel/idle.c > > @@ -32,6 +32,8 @@ > > #include > > #include > > #include > > + > > +static unsigned long msr_save; > > Why is this global? I'll change this to declare it in cpu_idle(). > > > #ifdef CONFIG_HOTPLUG_CPU > > /* this is used for software suspend, and that shuts down > > @@ -88,6 +90,10 @@ void cpu_idle(void) > > HMT_low(); > > HMT_very_low(); > > } > > + > > + /* set wait state MSR */ > > + msr_save = mfmsr(); > > + mtmsr(msr_save|MSR_WE); > > } > > > > HMT_medium(); > > The code you are modifying is common to all PowerPC kernels. Why didn't > you use the power_save() hook provided to you? > power_save() is called with interrupts disabled. So we would never wake up. ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ kvm-ppc-devel mailing list kvm-ppc-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-ppc-devel