From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH 4/4] kvm: Implement PEBS virtualization Date: Tue, 10 Jun 2014 12:22:07 -0700 Message-ID: <20140610192207.GC8178@tassilo.jf.intel.com> References: <1401412327-14810-1-git-send-email-andi@firstfloor.org> <1401412327-14810-5-git-send-email-andi@firstfloor.org> <20140610180448.GA9485@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , peterz@infradead.org, gleb@kernel.org, pbonzini@redhat.com, eranian@google.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: Marcelo Tosatti Return-path: Content-Disposition: inline In-Reply-To: <20140610180448.GA9485@amt.cnet> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Tue, Jun 10, 2014 at 03:04:48PM -0300, Marcelo Tosatti wrote: > On Thu, May 29, 2014 at 06:12:07PM -0700, Andi Kleen wrote: > > { > > struct kvm_pmu *pmu = &vcpu->arch.pmu; > > @@ -407,6 +551,20 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > > return 0; > > } > > break; > > + case MSR_IA32_DS_AREA: > > + pmu->ds_area = data; > > + return 0; > > + case MSR_IA32_PEBS_ENABLE: > > + if (data & ~0xf0000000fULL) > > + break; > > Bit 63 == PS_ENABLE ? PEBS_EN is [3:0] for each counter, but only one bit on Silvermont. LL_EN is [36:32], but currently unused. > > > void kvm_handle_pmu_event(struct kvm_vcpu *vcpu) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > > index 33e8c02..4f39917 100644 > > --- a/arch/x86/kvm/vmx.c > > +++ b/arch/x86/kvm/vmx.c > > @@ -7288,6 +7288,12 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) > > atomic_switch_perf_msrs(vmx); > > debugctlmsr = get_debugctlmsr(); > > > > + /* Move this somewhere else? */ > > Unless you hook into vcpu->arch.pmu.ds_area and perf_get_ds_area() > writers, it has to be at every vcpu entry. > > Could compare values in MSR save area to avoid switch. Ok. > > > + if (vcpu->arch.pmu.ds_area) > > + add_atomic_switch_msr(vmx, MSR_IA32_DS_AREA, > > + vcpu->arch.pmu.ds_area, > > + perf_get_ds_area()); > > Should clear_atomic_switch_msr before > add_atomic_switch_msr. Ok. BTW how about general PMU migration? As far as I can tell there is no code to save/restore the state for that currently, right? -Andi -- ak@linux.intel.com -- Speaking for myself only