From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Jones Subject: Re: [KVM x86 vPMU Patch 2/2] KVM: x86/vPMU: Fix unnecessary signed extension for AMD PERFCTRn Date: Tue, 11 Aug 2015 09:33:18 +0200 Message-ID: <20150811073318.GE4441@hawk.localdomain> References: <1438977210-24787-1-git-send-email-wei@redhat.com> <1438977210-24787-3-git-send-email-wei@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, gleb@kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, joro@8bytes.org, trivial@kernel.org To: Wei Huang Return-path: Content-Disposition: inline In-Reply-To: <1438977210-24787-3-git-send-email-wei@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Fri, Aug 07, 2015 at 03:53:30PM -0400, Wei Huang wrote: > According to AMD programmer's manual, AMD PERFCTRn is 64-bit MSR which, > unlike Intel perf counters, doesn't require signed extension. This > patch removes the unnecessary conversion in SVM vPMU code when PERFCTRn > is being updated. > > Signed-off-by: Wei Huang > --- > arch/x86/kvm/pmu_amd.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/arch/x86/kvm/pmu_amd.c b/arch/x86/kvm/pmu_amd.c > index 886aa25..39b9112 100644 > --- a/arch/x86/kvm/pmu_amd.c > +++ b/arch/x86/kvm/pmu_amd.c > @@ -133,8 +133,6 @@ static int amd_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > /* MSR_K7_PERFCTRn */ > pmc = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0); > if (pmc) { > - if (!msr_info->host_initiated) > - data = (s64)data; > pmc->counter += data - pmc_read_counter(pmc); > return 0; > } > -- > 1.8.3.1 Reviewed-by: Andrew Jones