From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752540Ab2IEGfb (ORCPT ); Wed, 5 Sep 2012 02:35:31 -0400 Received: from mail-we0-f174.google.com ([74.125.82.174]:59088 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751077Ab2IEGf3 (ORCPT ); Wed, 5 Sep 2012 02:35:29 -0400 Date: Wed, 5 Sep 2012 08:35:24 +0200 From: Ingo Molnar To: "Yan, Zheng" Cc: a.p.zijlstra@chello.nl, eranian@google.com, mingo@elte.hu, andi@firstfloor.org, avi@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] perf/x86: Disable uncore on virtualized CPU. Message-ID: <20120905063524.GA20710@gmail.com> References: <1345540117-14164-1-git-send-email-zheng.z.yan@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1345540117-14164-1-git-send-email-zheng.z.yan@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Yan, Zheng wrote: > From: "Yan, Zheng" > > Initializing uncore PMU on virtualized CPU may hang the kernel. > This is because kvm does not emulate the entire hardware. Thers > are lots of uncore related MSRs, making kvm enumerate them all > is a non-trival task. So just disable uncore on virtualized CPU. > > Signed-off-by: Yan, Zheng > --- > arch/x86/kernel/cpu/perf_event_intel_uncore.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c > index 0a55710..2f005ba 100644 > --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c > +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c > @@ -2898,6 +2898,9 @@ static int __init intel_uncore_init(void) > if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) > return -ENODEV; > > + if (cpu_has_hypervisor) > + return -ENODEV; > + > ret = uncore_pci_init(); > if (ret) > goto fail; Cannot the presence of the uncore hardware be detected in a cleaner fashion, via the PCI config space and such? Thanks, Ingo