From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH v2] KVM: x86: Prevent exposing TSC deadline timer feature in the absence of in-kernel APIC Date: Wed, 21 Dec 2011 12:58:33 +0100 Message-ID: <4EF1C9E9.50805@siemens.com> References: <4EF1146D.208@siemens.com> <4EF1B081.3010109@siemens.com> <4EF1B423.8050707@siemens.com> <4EF1B67D.7010603@redhat.com> <4EF1B7C0.3080200@siemens.com> <4 EF1B8A4.2050008@redhat.com> <4EF1C2DD.8070303@siemens.com> <4EF1C6C5.6080300@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Linus Torvalds , Alexey Zaytsev , "Liu, Jinsong" , Kernel development list , Marcelo Tosatti , "Garrett D'Amore" , kvm To: Avi Kivity Return-path: In-Reply-To: <4EF1C6C5.6080300@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 2011-12-21 12:45, Avi Kivity wrote: > On 12/21/2011 01:28 PM, Jan Kiszka wrote: >>> >>> timer_mode_mask can just be slaved to the bit (as received by >>> KVM_SET_CPUID); that's exactly kvm_update_cpuid()'s role. >> >> Like > > Ugh, the facebook generation invades lkml. I'm not on facebook. Does anyone sell shirts with that? > >> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c >> index 230f713..89b02bf 100644 >> --- a/arch/x86/kvm/cpuid.c >> +++ b/arch/x86/kvm/cpuid.c >> @@ -27,7 +27,6 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu) >> { >> struct kvm_cpuid_entry2 *best; >> struct kvm_lapic *apic = vcpu->arch.apic; >> - u32 timer_mode_mask; >> >> best = kvm_find_cpuid_entry(vcpu, 1, 0); >> if (!best) >> @@ -40,15 +39,12 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu) >> best->ecx |= bit(X86_FEATURE_OSXSAVE); >> } >> >> - if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && >> - best->function == 0x1) { >> - best->ecx |= bit(X86_FEATURE_TSC_DEADLINE_TIMER); >> - timer_mode_mask = 3 << 17; >> - } else >> - timer_mode_mask = 1 << 17; >> - >> - if (apic) >> - apic->lapic_timer.timer_mode_mask = timer_mode_mask; >> + if (apic) { >> + if (best->ecx & bit(X86_FEATURE_TSC_DEADLINE_TIMER)) >> + apic->lapic_timer.timer_mode_mask = 3 << 17; >> + else >> + apic->lapic_timer.timer_mode_mask = 1 << 17; >> + } >> >> kvm_pmu_cpuid_update(vcpu); >> } >> >> >> + the KVM_CAP thing? >> > > +1 Ah, the adult crowd that trusts the other side. OK, will see that I can cook up a proper patch later. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux