From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: PPC: Don't sync timebase when inside VM Date: Mon, 22 Jul 2013 17:19:08 -0500 Message-ID: <20130722221908.GA26079@home.buserror.net> References: <1330697553-27156-1-git-send-email-agraf@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: , , To: Alexander Graf Return-path: Content-Disposition: inline In-Reply-To: <1330697553-27156-1-git-send-email-agraf@suse.de> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Fri, Mar 02, 2012 at 03:12:33PM +0100, Alexander Graf wrote: > When running inside a virtual machine, we can not modify timebase, so > let's just not call the functions for it then. > > This resolves hangs when booting e500 SMP guests on overcommitted hosts. > > Reported-by: Stuart Yoder > Signed-off-by: Alexander Graf > > --- > arch/powerpc/platforms/85xx/smp.c | 7 +++++++ > 1 files changed, 7 insertions(+), 0 deletions(-) > > diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c > index ff42490..d4b6c1f 100644 > --- a/arch/powerpc/platforms/85xx/smp.c > +++ b/arch/powerpc/platforms/85xx/smp.c > @@ -249,6 +249,13 @@ void __init mpc85xx_smp_init(void) > smp_85xx_ops.cause_ipi = doorbell_cause_ipi; > } > > + /* When running under a hypervisor, we can not modify tb */ > + np = of_find_node_by_path("/hypervisor"); > + if (np) { > + smp_85xx_ops.give_timebase = NULL; > + smp_85xx_ops.take_timebase = NULL; > + } I'm marking this superseded as we now only set give/take_timebase if a guts node is present that corresponds to an SMP SoC. QEMU currently advertises an mpc8544 guts (which is not SMP) and will eventually move to a paravirt device with no guts at all. -Scott