From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v2] perf/x86: Fix HO/GO counting with SVM disabled Date: Wed, 29 Feb 2012 19:00:09 +0200 Message-ID: <4F4E5999.6080600@redhat.com> References: <1330444544-15665-1-git-send-email-joerg.roedel@amd.com> <1330523852-19566-1-git-send-email-joerg.roedel@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, joro@8bytes.org, Peter Zijlstra , Ingo Molnar , Stephane Eranian , David Ahern , Gleb Natapov , Robert Richter To: Joerg Roedel Return-path: In-Reply-To: <1330523852-19566-1-git-send-email-joerg.roedel@amd.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 02/29/2012 03:57 PM, Joerg Roedel wrote: > It turned out that a performance counter on AMD does not > count at all when the GO or HO bit is set in the control > register and SVM is disabled in EFER. > > This patch works around this issue by masking out the HO bit > in the performance counter control register when SVM is not > enabled. > > The GO bit is not touched because it is only set when the > user wants to count in guest-mode only. So when SVM is > disabled the counter should not run at all and the > not-counting is the intended behaviour. > > diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c > index 0397b23..67250a5 100644 > --- a/arch/x86/kernel/cpu/perf_event_amd.c > +++ b/arch/x86/kernel/cpu/perf_event_amd.c > @@ -1,4 +1,5 @@ > #include > +#include > #include > #include > #include > @@ -357,7 +358,9 @@ static void amd_pmu_cpu_starting(int cpu) > struct amd_nb *nb; > int i, nb_id; > > - if (boot_cpu_data.x86_max_cores < 2) > + cpuc->perf_ctr_virt_mask = AMD_PERFMON_EVENTSEL_HOSTONLY; > + > + if (boot_cpu_data.x86_max_cores < 2 || boot_cpu_data.x86 == 0x15) > return; Why this (boot_cpu_data.x86 == 0x15) change? -- error compiling committee.c: too many arguments to function