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=-6.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,UNWANTED_LANGUAGE_BODY,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 2ECACC04AA7 for ; Wed, 15 May 2019 04:12:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E9DCF20881 for ; Wed, 15 May 2019 04:12:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="O5DmFBxI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726808AbfEOEMK (ORCPT ); Wed, 15 May 2019 00:12:10 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:39238 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726757AbfEOEMG (ORCPT ); Wed, 15 May 2019 00:12:06 -0400 Received: by mail-pf1-f193.google.com with SMTP id z26so642582pfg.6; Tue, 14 May 2019 21:12:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=FRhCay0gyIZMyq2UxiW86hyINdu7rUa3vMrWeCWaFDM=; b=O5DmFBxInL1znEntSZUdWv14ySAL1DedU+4BXCp3nCmh+agvC49VoGi03K6JvF0sBb JiUEOGVORhmrXFp3oF1xVqB5qOI1yIUMOjpHyIUtjKJp+1cy9NbjD5mViQQBmCmY0Ege bfmWLkm4FUYA6+Gh6ZscewV9A1Pnj11IOZvyinsEtnvt9VPeskeFqH2LELa0pk0gc2RV JT+U5E/MnplEmfDwxGfMLTfm5QSi6SjL6KRPMX5WXLgUDRwJ/49uowQ+xzoD4xNV3xsO m7qkupDGHWNsdAiG65MGjGmY5WVwpczTwYKEKM+T+L3JI/xMjAOyHFuhaocIIk1il4tW frGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=FRhCay0gyIZMyq2UxiW86hyINdu7rUa3vMrWeCWaFDM=; b=Dug4m+gDsHPzBs8UYHRvEeEVVBi/J8vxC+KoKlO03uWAmqm+bSUps49UG2gtxXlxO+ 3WyNWAYk3tvvHROw4HbW0XGMNDo+FERQ6KuP1wWtwTyJsgX07XUfMZbyoyrfu8qbr6gF D9t6GoiUFdHA1l3XH++bbnxQ3kQ60SmdcFRaxFVSKAeKHo+J1JweA5AhtYdTb9+vkQX+ g14iAKdSR8w88zOsHSRvFMhS4I+MeNBYUuXJN5u+Rxlsr+cIx2COHCZzdS5ma/cRdwWT eDI9I/t5lbKlqAecORLIJzpenTupoOdVKW8EB8Zw+y1R8kxZNnlM/vB20oUiXvWvZ81d M9ew== X-Gm-Message-State: APjAAAUnJFEAFr7irI3Zm+Pdl5ETmvjE4g2Zt7K0Fx2g4QE3FxDTkUBs ZSnqxCN4t+7XkajL0bQdOZ/Wl8wD X-Google-Smtp-Source: APXvYqzhqFk7NcnrFTbfIPAe1Jjma/LpjFuu7hN++1aib1F5Qvbomku1fp0U4AMcJLhB8/96lJdinw== X-Received: by 2002:a65:5304:: with SMTP id m4mr21540788pgq.126.1557893525249; Tue, 14 May 2019 21:12:05 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.123]) by smtp.googlemail.com with ESMTPSA id z187sm886788pfb.132.2019.05.14.21.12.03 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 14 May 2019 21:12:04 -0700 (PDT) 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?= , Sean Christopherson , Liran Alon Subject: [PATCH v2 3/4] KVM: LAPIC: Expose per-vCPU timer adavance information to userspace Date: Wed, 15 May 2019 12:11:53 +0800 Message-Id: <1557893514-5815-4-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1557893514-5815-1-git-send-email-wanpengli@tencent.com> References: <1557893514-5815-1-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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li Expose the per-vCPU advancement information to the user via per-vCPU debugfs entry. wait_lapic_expire() call was moved above guest_enter_irqoff() because of its tracepoint, which violated the RCU extended quiescent state invoked by guest_enter_irqoff()[1][2]. This patch simply removes the tracepoint, which would allow moving wait_lapic_expire(). Sean pointed out: | Now that the advancement time is tracked per-vCPU, realizing a change | in the advancement time requires creating a new VM. For all intents | and purposes this makes it impractical to hand tune the advancement | in real time using the tracepoint as the feedback mechanism. [1] Commit 8b89fe1f6c43 ("kvm: x86: move tracepoints outside extended quiescent state") [2] https://patchwork.kernel.org/patch/7821111/ Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Sean Christopherson Cc: Liran Alon Signed-off-by: Wanpeng Li --- arch/x86/kvm/debugfs.c | 16 ++++++++++++++++ arch/x86/kvm/lapic.c | 16 ++++++++-------- arch/x86/kvm/lapic.h | 1 + arch/x86/kvm/trace.h | 20 -------------------- 4 files changed, 25 insertions(+), 28 deletions(-) diff --git a/arch/x86/kvm/debugfs.c b/arch/x86/kvm/debugfs.c index c19c7ed..8cf542e 100644 --- a/arch/x86/kvm/debugfs.c +++ b/arch/x86/kvm/debugfs.c @@ -9,12 +9,22 @@ */ #include #include +#include "lapic.h" bool kvm_arch_has_vcpu_debugfs(void) { return true; } +static int vcpu_get_timer_expire_delta(void *data, u64 *val) +{ + struct kvm_vcpu *vcpu = (struct kvm_vcpu *) data; + *val = vcpu->arch.apic->lapic_timer.advance_expire_delta; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(vcpu_timer_expire_delta_fops, vcpu_get_timer_expire_delta, NULL, "%lld\n"); + static int vcpu_get_tsc_offset(void *data, u64 *val) { struct kvm_vcpu *vcpu = (struct kvm_vcpu *) data; @@ -51,6 +61,12 @@ int kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu) if (!ret) return -ENOMEM; + ret = debugfs_create_file("advance_expire_delta", 0444, + vcpu->debugfs_dentry, + vcpu, &vcpu_timer_expire_delta_fops); + if (!ret) + return -ENOMEM; + if (kvm_has_tsc_control) { ret = debugfs_create_file("tsc-scaling-ratio", 0444, vcpu->debugfs_dentry, diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 2f364fe..af38ece 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1502,27 +1502,27 @@ static inline void __wait_lapic_expire(struct kvm_vcpu *vcpu, u64 guest_cycles) } static inline void adaptive_tune_timer_advancement(struct kvm_vcpu *vcpu, - u64 guest_tsc, u64 tsc_deadline) + s64 advance_expire_delta) { struct kvm_lapic *apic = vcpu->arch.apic; u32 timer_advance_ns = apic->lapic_timer.timer_advance_ns; u64 ns; /* too early */ - if (guest_tsc < tsc_deadline) { - ns = (tsc_deadline - guest_tsc) * 1000000ULL; + if (advance_expire_delta < 0) { + ns = -advance_expire_delta * 1000000ULL; do_div(ns, vcpu->arch.virtual_tsc_khz); timer_advance_ns -= min((u32)ns, timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP); } else { /* too late */ - ns = (guest_tsc - tsc_deadline) * 1000000ULL; + ns = advance_expire_delta * 1000000ULL; do_div(ns, vcpu->arch.virtual_tsc_khz); timer_advance_ns += min((u32)ns, timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP); } - if (abs(guest_tsc - tsc_deadline) < LAPIC_TIMER_ADVANCE_ADJUST_DONE) + if (abs(advance_expire_delta) < LAPIC_TIMER_ADVANCE_ADJUST_DONE) apic->lapic_timer.timer_advance_adjust_done = true; if (unlikely(timer_advance_ns > 5000)) { timer_advance_ns = 0; @@ -1545,13 +1545,13 @@ void wait_lapic_expire(struct kvm_vcpu *vcpu) tsc_deadline = apic->lapic_timer.expired_tscdeadline; apic->lapic_timer.expired_tscdeadline = 0; guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc()); - trace_kvm_wait_lapic_expire(vcpu->vcpu_id, guest_tsc - tsc_deadline); + apic->lapic_timer.advance_expire_delta = guest_tsc - tsc_deadline; - if (guest_tsc < tsc_deadline) + if (apic->lapic_timer.advance_expire_delta < 0) __wait_lapic_expire(vcpu, tsc_deadline - guest_tsc); if (unlikely(!apic->lapic_timer.timer_advance_adjust_done)) - adaptive_tune_timer_advancement(vcpu, guest_tsc, tsc_deadline); + adaptive_tune_timer_advancement(vcpu, apic->lapic_timer.advance_expire_delta); } static void start_sw_tscdeadline(struct kvm_lapic *apic) diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index d6d049b..3e72a25 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -32,6 +32,7 @@ struct kvm_timer { u64 tscdeadline; u64 expired_tscdeadline; u32 timer_advance_ns; + s64 advance_expire_delta; atomic_t pending; /* accumulated triggered timers */ bool hv_timer_in_use; bool timer_advance_adjust_done; diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h index 4d47a26..3f9bc62 100644 --- a/arch/x86/kvm/trace.h +++ b/arch/x86/kvm/trace.h @@ -953,26 +953,6 @@ TRACE_EVENT(kvm_pvclock_update, __entry->flags) ); -TRACE_EVENT(kvm_wait_lapic_expire, - TP_PROTO(unsigned int vcpu_id, s64 delta), - TP_ARGS(vcpu_id, delta), - - TP_STRUCT__entry( - __field( unsigned int, vcpu_id ) - __field( s64, delta ) - ), - - TP_fast_assign( - __entry->vcpu_id = vcpu_id; - __entry->delta = delta; - ), - - TP_printk("vcpu %u: delta %lld (%s)", - __entry->vcpu_id, - __entry->delta, - __entry->delta < 0 ? "early" : "late") -); - TRACE_EVENT(kvm_enter_smm, TP_PROTO(unsigned int vcpu_id, u64 smbase, bool entering), TP_ARGS(vcpu_id, smbase, entering), -- 2.7.4