From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F090C54EEB for ; Mon, 27 Apr 2020 18:42:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D78821D7A for ; Mon, 27 Apr 2020 18:42:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726252AbgD0Smy (ORCPT ); Mon, 27 Apr 2020 14:42:54 -0400 Received: from mga12.intel.com ([192.55.52.136]:26249 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726223AbgD0Smy (ORCPT ); Mon, 27 Apr 2020 14:42:54 -0400 IronPort-SDR: ab4v1RvQvQZYo7MJONB2yglj2v1qt3VZR3gxKnv7Ql2STrRSSG+qF8r6F87lP+JkEqz4qkSJdI TILaIn7db2AA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Apr 2020 11:42:54 -0700 IronPort-SDR: XpoGt/OpVhcESU1Pjd1d9Ljez4WXwDlvyO41N/XKPWTN49Dt8KyUsT3hJso7snho9gkE5n3Soi epzqOcMcKKyA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,325,1583222400"; d="scan'208";a="431876032" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.202]) by orsmga005.jf.intel.com with ESMTP; 27 Apr 2020 11:42:53 -0700 Date: Mon, 27 Apr 2020 11:42:53 -0700 From: Sean Christopherson To: Wanpeng Li Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Haiwei Li Subject: Re: [PATCH v3 5/5] KVM: VMX: Handle preemption timer fastpath Message-ID: <20200427184253.GR14870@linux.intel.com> References: <1587709364-19090-1-git-send-email-wanpengli@tencent.com> <1587709364-19090-6-git-send-email-wanpengli@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1587709364-19090-6-git-send-email-wanpengli@tencent.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, Apr 24, 2020 at 02:22:44PM +0800, Wanpeng Li wrote: > From: Wanpeng Li > > This patch implements handle preemption timer fastpath, after timer fire > due to VMX-preemption timer counts down to zero, handle it as soon as > possible and vmentry immediately without checking various kvm stuff when > possible. > > Testing on SKX Server. > > cyclictest in guest(w/o mwait exposed, adaptive advance lapic timer is default -1): > > 5540.5ns -> 4602ns 17% > > kvm-unit-test/vmexit.flat: > > w/o avanced timer: > tscdeadline_immed: 2885 -> 2431.25 15.7% > tscdeadline: 5668.75 -> 5188.5 8.4% > > w/ adaptive advance timer default -1: > tscdeadline_immed: 2965.25 -> 2520 15.0% > tscdeadline: 4663.75 -> 4537 2.7% > > Tested-by: Haiwei Li > Cc: Haiwei Li > Signed-off-by: Wanpeng Li > --- > arch/x86/kvm/vmx/vmx.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index d21b66b..028967a 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -6560,12 +6560,28 @@ void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) > } > } > > +static enum exit_fastpath_completion handle_fastpath_preemption_timer(struct kvm_vcpu *vcpu) Somewhat offtopic, would it make sense to add a fastpath_t typedef? These enum lines are a bit long... > +{ > + struct vcpu_vmx *vmx = to_vmx(vcpu); > + > + if (!vmx->req_immediate_exit && > + !unlikely(vmx->loaded_vmcs->hv_timer_soft_disabled)) { Bad indentation. Also, this is is identical to handle_preemption_timer(), why not something like: static bool __handle_preemption_timer(struct vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); if (!vmx->req_immediate_exit && !unlikely(vmx->loaded_vmcs->hv_timer_soft_disabled)) { kvm_lapic_expired_hv_timer(vcpu); return true; } return false; } static enum exit_fastpath_completion handle_fastpath_preemption_timer(struct kvm_vcpu *vcpu) { if (__handle_preemption_timer(vcpu)) return EXIT_FASTPATH_CONT_RUN; return EXIT_FASTPATH_NONE; } static int handle_preemption_timer(struct kvm_vcpu *vcpu) { __handle_preemption_timer(vcpu); return 1; } > + kvm_lapic_expired_hv_timer(vcpu); > + trace_kvm_exit(EXIT_REASON_PREEMPTION_TIMER, vcpu, KVM_ISA_VMX); > + return EXIT_FASTPATH_CONT_RUN; > + } > + > + return EXIT_FASTPATH_NONE; > +} > + > static enum exit_fastpath_completion vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) > { > if (!is_guest_mode(vcpu) && vcpu->arch.apicv_active) { > switch (to_vmx(vcpu)->exit_reason) { > case EXIT_REASON_MSR_WRITE: > return handle_fastpath_set_msr_irqoff(vcpu); > + case EXIT_REASON_PREEMPTION_TIMER: > + return handle_fastpath_preemption_timer(vcpu); > default: > return EXIT_FASTPATH_NONE; > } > -- > 2.7.4 >