From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: [PATCH] KVM: PPC: e500: Don't hardcode PIR=0 Date: Fri, 2 Sep 2011 14:35:25 -0500 Message-ID: <4E612FFD.8000300@freescale.com> References: <20110901230851.GA26220@schlenkerla.am.freescale.net> <9E450E07-D406-4666-AE9C-F879944EDDB8@suse.de> <4E611D1F.9010409@freescale.com> <1C0EA3C2-5994-4AEA-92C0-346981AB994D@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: "" , "" To: Alexander Graf Return-path: In-Reply-To: <1C0EA3C2-5994-4AEA-92C0-346981AB994D@suse.de> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 09/02/2011 02:23 PM, Alexander Graf wrote: > > On 02.09.2011, at 20:14, Scott Wood wrote: > >> On 09/02/2011 10:12 AM, Alexander Graf wrote: >>> >>> Am 02.09.2011 um 01:08 schrieb Scott Wood : >>> >>>> Signed-off-by: Scott Wood >>> >>> Patch description missing. >> >> It's not missing, it's just brief. :-) >> >> I suppose you could add "The hardcoded behavior prevents SMP support. >> QEMU shall specify the vcpu's PIR as the vcpu id". > > Ok, let me get my head around this. Before, PIR was forced to 0 by > the setup code and set_sregs with PIR != 0 failed. Now it's simply > vcpu_id which is already the correct value. Why didn't I run into > this failure? Why did SMP work for me at all then? Shouldn't the > guest be completely confused and find two CPU 0s? I was wondering about that myself. It looks like PIR isn't used much in Linux on e500v2. There's no msgsnd. It's used to for __secondary_hold_acknowledge, but that has a silent timeout. -Scott