From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754301Ab2IFLcy (ORCPT ); Thu, 6 Sep 2012 07:32:54 -0400 Received: from mailxx.hitachi.co.jp ([133.145.228.50]:59866 "EHLO mailxx.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751022Ab2IFLcr (ORCPT ); Thu, 6 Sep 2012 07:32:47 -0400 X-AuditID: b753bd60-91ec3ba0000047ca-e2-504888da0c75 X-AuditID: b753bd60-91ec3ba0000047ca-e2-504888da0c75 From: Tomoki Sekiyama Subject: [RFC v2 PATCH 11/21] KVM: no exiting from guest when slave CPU halted To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, x86@kernel.org, yrl.pp-manager.tt@hitachi.com, Avi Kivity , Marcelo Tosatti , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Date: Thu, 06 Sep 2012 20:28:16 +0900 Message-ID: <20120906112816.13320.71132.stgit@kvmdev> In-Reply-To: <20120906112718.13320.8231.stgit@kvmdev> References: <20120906112718.13320.8231.stgit@kvmdev> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Avoid exiting from a guest on slave CPU even if HLT instruction is executed. Since the slave CPU is dedicated to a vCPU, exit on HLT is not required, and avoiding VM exit will improve the guest's performance. This is a partial revert of 10166744b80a ("KVM: VMX: remove yield_on_hlt") Cc: Avi Kivity Cc: Marcelo Tosatti Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" --- arch/x86/kvm/vmx.c | 25 ++++++++++++++++++++++++- 1 files changed, 24 insertions(+), 1 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index d99bee6..03a2d02 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -1698,9 +1698,29 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu) vmx_set_interrupt_shadow(vcpu, 0); } +static inline void vmx_clear_hlt(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_SLAVE_CPU + /* Ensure that we clear the HLT state in the VMCS. We don't need to + * explicitly skip the instruction because if the HLT state is set, + * then the instruction is already executing and RIP has already been + * advanced. */ + if (vcpu->arch.slave_cpu >= 0 && + vmcs_read32(GUEST_ACTIVITY_STATE) == GUEST_ACTIVITY_HLT) + vmcs_write32(GUEST_ACTIVITY_STATE, GUEST_ACTIVITY_ACTIVE); +#endif +} + static void vmx_set_slave_mode(struct kvm_vcpu *vcpu, bool slave) { - /* Nothing */ + /* Don't intercept the guest's halt on slave CPU */ + if (slave) { + vmcs_clear_bits(CPU_BASED_VM_EXEC_CONTROL, + CPU_BASED_HLT_EXITING); + } else { + vmcs_set_bits(CPU_BASED_VM_EXEC_CONTROL, + CPU_BASED_HLT_EXITING); + } } /* @@ -1755,6 +1775,7 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr, intr_info |= INTR_TYPE_HARD_EXCEPTION; vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr_info); + vmx_clear_hlt(vcpu); } static bool vmx_rdtscp_supported(void) @@ -4125,6 +4146,7 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu) } else intr |= INTR_TYPE_EXT_INTR; vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr); + vmx_clear_hlt(vcpu); } static void vmx_inject_nmi(struct kvm_vcpu *vcpu) @@ -4156,6 +4178,7 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu) } vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, INTR_TYPE_NMI_INTR | INTR_INFO_VALID_MASK | NMI_VECTOR); + vmx_clear_hlt(vcpu); } static int vmx_nmi_allowed(struct kvm_vcpu *vcpu)