From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from TX2EHSOBE006.bigfish.com (tx2ehsobe003.messaging.microsoft.com [65.55.88.13]) by ozlabs.org (Postfix) with ESMTP id 9DDD5B6EFF for ; Wed, 18 Aug 2010 04:28:44 +1000 (EST) Received: from mail26-tx2 (localhost.localdomain [127.0.0.1]) by mail26-tx2-R.bigfish.com (Postfix) with ESMTP id 9FD24E010D for ; Tue, 17 Aug 2010 18:28:31 +0000 (UTC) Received: from TX2EHSMHS033.bigfish.com (unknown [10.9.14.252]) by mail26-tx2.bigfish.com (Postfix) with ESMTP id E24AF1590051 for ; Tue, 17 Aug 2010 18:28:29 +0000 (UTC) Received: from az33smr02.freescale.net (az33smr02.freescale.net [10.64.34.200]) by az33egw02.freescale.net (8.14.3/8.14.3) with ESMTP id o7HISFkY016254 for ; Tue, 17 Aug 2010 11:28:25 -0700 (MST) Received: from az33exm25.fsl.freescale.net (az33exm25.am.freescale.net [10.64.32.16]) by az33smr02.freescale.net (8.13.1/8.13.0) with ESMTP id o7HISLJB000656 for ; Tue, 17 Aug 2010 13:28:21 -0500 (CDT) Date: Tue, 17 Aug 2010 13:28:13 -0500 From: Scott Wood To: Alexander Graf Subject: Re: [PATCH 21/26] KVM: PPC: Force enable nap on KVM Message-ID: <20100817132813.05efb21d@schlenkerla.am.freescale.net> In-Reply-To: <1282053481-18787-22-git-send-email-agraf@suse.de> References: <1282053481-18787-1-git-send-email-agraf@suse.de> <1282053481-18787-22-git-send-email-agraf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Cc: linuxppc-dev , KVM list , kvm-ppc@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 17 Aug 2010 15:57:56 +0200 Alexander Graf wrote: > There are some heuristics in the PPC power management code that try to find > out if the particular hardware we're running on supports proper power management > or just hangs the machine when going into nap mode. > > Since we know that KVM is safe with nap, let's force enable it in the PV code > once we're certain that we are on a KVM VM. Could this cause the cache to be flushed unnecessarily on e500? Where available, doze would probably be better for signalling the hypervisor that the guest is idle. > > Signed-off-by: Alexander Graf > --- > arch/powerpc/kernel/kvm.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c > index 517da39..95aed6b 100644 > --- a/arch/powerpc/kernel/kvm.c > +++ b/arch/powerpc/kernel/kvm.c > @@ -583,6 +583,9 @@ static int __init kvm_guest_init(void) > if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE)) > kvm_use_magic_page(); > > + /* Enable napping */ > + powersave_nap = 1; > + > free_tmp: > kvm_free_tmp(); >