From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967252AbeCAJt6 (ORCPT ); Thu, 1 Mar 2018 04:49:58 -0500 Received: from mail-pf0-f193.google.com ([209.85.192.193]:45262 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967087AbeCAJty (ORCPT ); Thu, 1 Mar 2018 04:49:54 -0500 X-Google-Smtp-Source: AG47ELs0HgM2EHfberb1HxMIjlw1G8AN1ub5mXYDDY7EZ2zRnqA2YO+D7Y5/EhWyX3PzOyEusNK5Wg== From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH 2/3] KVM: X86: Provides userspace with a capability to not intercept HLT Date: Thu, 1 Mar 2018 17:49:41 +0800 Message-Id: <1519897782-8124-2-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1519897782-8124-1-git-send-email-wanpengli@tencent.com> References: <1519897782-8124-1-git-send-email-wanpengli@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li If host CPUs are dedicated to a VM, we can avoid VM exits on HLT. This patch adds the per-VM non-HLT-exiting capability. Cc: Paolo Bonzini Cc: Radim Krčmář Signed-off-by: Wanpeng Li --- Documentation/virtual/kvm/api.txt | 1 + arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/svm.c | 3 +++ arch/x86/kvm/vmx.c | 23 +++++++++++++++++++++++ arch/x86/kvm/x86.c | 3 +++ arch/x86/kvm/x86.h | 9 ++++++++- 6 files changed, 39 insertions(+), 1 deletion(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 4df35c0..c07e775 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -4368,6 +4368,7 @@ Returns: 0 on success, -EINVAL when args[0] contains invalid exits Valid exits in args[0] are #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) +#define KVM_X86_DISABLE_EXITS_HLT (1 << 1) Enabling this capability on a VM provides userspace with a way to no longer intercepts some instructions for improved latency in some diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 6bd754f..ee739ad 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -808,6 +808,7 @@ struct kvm_arch { gpa_t wall_clock; bool mwait_in_guest; + bool hlt_in_guest; bool ept_identity_pagetable_done; gpa_t ept_identity_map_addr; diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index dff3a5d..fcf8339 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1394,6 +1394,9 @@ static void init_vmcb(struct vcpu_svm *svm) set_intercept(svm, INTERCEPT_MWAIT); } + if (!kvm_hlt_in_guest(svm->vcpu.kvm)) + set_intercept(svm, INTERCEPT_HLT); + control->iopm_base_pa = __sme_set(iopm_base); control->msrpm_base_pa = __sme_set(__pa(svm->msrpm)); control->int_ctl = V_INTR_MASKING_MASK; diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index b551067..f9f887a 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2525,6 +2525,19 @@ static int nested_vmx_check_exception(struct kvm_vcpu *vcpu, unsigned long *exit return 0; } +static void vmx_clear_hlt(struct kvm_vcpu *vcpu) +{ + /* + * 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 (kvm_hlt_in_guest(vcpu->kvm) && + vmcs_read32(GUEST_ACTIVITY_STATE) == GUEST_ACTIVITY_HLT) + vmcs_write32(GUEST_ACTIVITY_STATE, GUEST_ACTIVITY_ACTIVE); +} + static void vmx_queue_exception(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); @@ -2555,6 +2568,8 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu) 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) @@ -5504,6 +5519,8 @@ static u32 vmx_exec_control(struct vcpu_vmx *vmx) if (kvm_mwait_in_guest(vmx->vcpu.kvm)) exec_control &= ~(CPU_BASED_MWAIT_EXITING | CPU_BASED_MONITOR_EXITING); + if (kvm_hlt_in_guest(vmx->vcpu.kvm)) + exec_control &= ~CPU_BASED_HLT_EXITING; return exec_control; } @@ -5865,6 +5882,8 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) update_exception_bitmap(vcpu); vpid_sync_context(vmx->vpid); + if (init_event) + vmx_clear_hlt(vcpu); } /* @@ -5936,6 +5955,8 @@ 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) @@ -5966,6 +5987,8 @@ 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 bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c1d9bbb..13f01d7 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2845,6 +2845,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = KVM_CLOCK_TSC_STABLE; break; case KVM_CAP_X86_DISABLE_EXITS: + r |= KVM_X86_DISABLE_EXITS_HTL; if(kvm_mwait_can_in_guest()) r |= KVM_X86_DISABLE_EXITS_MWAIT; break; @@ -4199,6 +4200,8 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if ((cap->args[0] & KVM_X86_DISABLE_EXITS_MWAIT) && kvm_mwait_can_in_guest()) kvm->arch.mwait_in_guest = true; + if (cap->args[0] & KVM_X86_DISABLE_EXITS_HTL) + kvm->arch.hlt_in_guest = true; r = 0; break; default: diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index cd1215e..d4ddb00 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -263,11 +263,18 @@ static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec) }) #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) -#define KVM_X86_DISABLE_VALID_EXITS (KVM_X86_DISABLE_EXITS_MWAIT) +#define KVM_X86_DISABLE_EXITS_HTL (1 << 1) +#define KVM_X86_DISABLE_VALID_EXITS (KVM_X86_DISABLE_EXITS_MWAIT | \ + KVM_X86_DISABLE_EXITS_HTL) static inline bool kvm_mwait_in_guest(struct kvm *kvm) { return kvm->arch.mwait_in_guest; } +static inline bool kvm_hlt_in_guest(struct kvm *kvm) +{ + return kvm->arch.hlt_in_guest; +} + #endif -- 2.7.4