From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH 7/9] KVM: Expose the architectural performance monitoring CPUID leaf Date: Tue, 1 Nov 2011 18:18:15 +0200 Message-ID: <20111101161815.GB16539@redhat.com> References: <1319993624-20247-1-git-send-email-gleb@redhat.com> <1319993624-20247-8-git-send-email-gleb@redhat.com> <4EB01507.1020607@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, avi@redhat.com, mtosatti@redhat.com, linux-kernel@redhat.com, mingo@elte.hu, a.p.zijlstra@chello.nl, acme@ghostprotocols.net To: David Ahern Return-path: Received: from mx1.redhat.com ([209.132.183.28]:8415 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752858Ab1KAQSb (ORCPT ); Tue, 1 Nov 2011 12:18:31 -0400 Content-Disposition: inline In-Reply-To: <4EB01507.1020607@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Nov 01, 2011 at 09:49:27AM -0600, David Ahern wrote: > On 10/30/2011 10:53 AM, Gleb Natapov wrote: > > From: Avi Kivity > > > > Provide a CPUID leaf that describes the emulated PMU. > > > > Signed-off-by: Avi Kivity > > Signed-off-by: Gleb Natapov > > --- > > arch/x86/kvm/x86.c | 23 ++++++++++++++++++++++- > > 1 files changed, 22 insertions(+), 1 deletions(-) > > > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 5ea4cb8..56153a9 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -2543,6 +2543,28 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, > > } > > case 9: > > break; > > + case 0xa: { /* Architectural Performance Monitoring */ > > + struct x86_pmu_capability cap; > > + > > + perf_get_x86_pmu_capability(&cap); > > + > > + /* > > + * Only support guest architectural pmu on a host > > + * with architectural pmu. > > + */ > > + if (!cap.version) > > + memset(&cap, 0, sizeof(cap)); > > + > > + entry->eax = min(cap.version, 2) > > + | (cap.num_counters_gp << 8) > > + | (cap.bit_width_gp << 16) > > + | (cap.events_mask_len << 24); > > + entry->ebx = cap.events_mask; > > + entry->ecx = 0; > > + entry->edx = cap.num_counters_fixed > > + | (cap.bit_width_fixed << 5); > > + break; > > + } > > If PERF_EVENTS is disabled in the host kernel will KVM return the right > thing for the guest that might have PERF_EVENTS enabled? > With correct implementation of perf_get_x86_pmu_capability() it should. PERF_EVENTS disable version should set cap.version to zero, so guest will find that vcpu does not provide architectural PMU. > David > > > > /* function 0xb has additional index. */ > > case 0xb: { > > int i, level_type; > > @@ -2637,7 +2659,6 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, > > case 3: /* Processor serial number */ > > case 5: /* MONITOR/MWAIT */ > > case 6: /* Thermal management */ > > - case 0xA: /* Architectural Performance Monitoring */ > > case 0x80000007: /* Advanced power management */ > > case 0xC0000002: > > case 0xC0000003: -- Gleb.