From patchwork Thu May 6 12:14:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: thermal-bot for Julien Panis X-Patchwork-Id: 432511 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=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS 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 107CCC43462 for ; Thu, 6 May 2021 12:14:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D6CB2613F0 for ; Thu, 6 May 2021 12:14:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233020AbhEFMPH (ORCPT ); Thu, 6 May 2021 08:15:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44848 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232938AbhEFMPF (ORCPT ); Thu, 6 May 2021 08:15:05 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7AEEEC061574; Thu, 6 May 2021 05:14:07 -0700 (PDT) Date: Thu, 06 May 2021 12:14:04 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1620303245; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5cnn4Fmmyn5WvE4AFKiO+TAVCk9EaZgQjTJEq3MOtSY=; b=sIv0zeoqLgyiO9BrLDO3dXP3dknF9Z2m37As+abuS9FrUaYKzfKSgEuH7gB4YuaDaHsKCI t0Zg00pfgb12CW5OoYuzVgLBalQ7WJjrAu4e1RCL1+TsyFkLlUuZH9rHTd4CKxskcaX6Dk ZosOGG+Yu6xR5+j8o9QiY1LHDxxsrVNymyX4ORHLA9FIVoEexlXVi4oBgM7PtGbOxTdVQk jKPUkwWUAGDWHKMcq2J9U74toN6gF/R6NAh1C3hHdJYHm35m2YKPZHc2UsgC4nitLVMJ+x RpWgI/yyRfYkSQ8C+05jFtRr0Jj5wBv4RixyLJUchkNHQVBJ0sLsZpq2Y5csCg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1620303245; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5cnn4Fmmyn5WvE4AFKiO+TAVCk9EaZgQjTJEq3MOtSY=; b=fp0jkOIOygAPKfy+OJlYcv/J8jIDzNAcrvKgrEM+ePoz5USZIzydyjRZkCz1PprKt4Ekdi IHvKl017xGgFzhDA== From: "tip-bot2 for Wanpeng Li" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] KVM: x86: Defer vtime accounting 'til after IRQ handling Cc: Thomas Gleixner , Wanpeng Li , Sean Christopherson , stable@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210505002735.1684165-4-seanjc@google.com> References: <20210505002735.1684165-4-seanjc@google.com> MIME-Version: 1.0 Message-ID: <162030324464.29796.14687279478344934242.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 160457140187c5fb127b844e5a85f87f00a01b14 Gitweb: https://git.kernel.org/tip/160457140187c5fb127b844e5a85f87f00a01b14 Author: Wanpeng Li AuthorDate: Tue, 04 May 2021 17:27:30 -07:00 Committer: Thomas Gleixner CommitterDate: Wed, 05 May 2021 22:54:11 +02:00 KVM: x86: Defer vtime accounting 'til after IRQ handling Defer the call to account guest time until after servicing any IRQ(s) that happened in the guest or immediately after VM-Exit. Tick-based accounting of vCPU time relies on PF_VCPU being set when the tick IRQ handler runs, and IRQs are blocked throughout the main sequence of vcpu_enter_guest(), including the call into vendor code to actually enter and exit the guest. This fixes a bug where reported guest time remains '0', even when running an infinite loop in the guest: https://bugzilla.kernel.org/show_bug.cgi?id=209831 Fixes: 87fa7f3e98a131 ("x86/kvm: Move context tracking where it belongs") Suggested-by: Thomas Gleixner Co-developed-by: Sean Christopherson Signed-off-by: Wanpeng Li Signed-off-by: Sean Christopherson Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210505002735.1684165-4-seanjc@google.com --- arch/x86/kvm/svm/svm.c | 6 +++--- arch/x86/kvm/vmx/vmx.c | 6 +++--- arch/x86/kvm/x86.c | 9 +++++++++ 3 files changed, 15 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 9790c73..c400def 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3753,15 +3753,15 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu) * have them in state 'on' as recorded before entering guest mode. * Same as enter_from_user_mode(). * - * guest_exit_irqoff() restores host context and reinstates RCU if - * enabled and required. + * context_tracking_guest_exit() restores host context and reinstates + * RCU if enabled and required. * * This needs to be done before the below as native_read_msr() * contains a tracepoint and x86_spec_ctrl_restore_host() calls * into world and some more. */ lockdep_hardirqs_off(CALLER_ADDR0); - guest_exit_irqoff(); + context_tracking_guest_exit(); instrumentation_begin(); trace_hardirqs_off_finish(); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index b21d751..e108fb4 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6703,15 +6703,15 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, * have them in state 'on' as recorded before entering guest mode. * Same as enter_from_user_mode(). * - * guest_exit_irqoff() restores host context and reinstates RCU if - * enabled and required. + * context_tracking_guest_exit() restores host context and reinstates + * RCU if enabled and required. * * This needs to be done before the below as native_read_msr() * contains a tracepoint and x86_spec_ctrl_restore_host() calls * into world and some more. */ lockdep_hardirqs_off(CALLER_ADDR0); - guest_exit_irqoff(); + context_tracking_guest_exit(); instrumentation_begin(); trace_hardirqs_off_finish(); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index cebdaa1..6eda283 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9315,6 +9315,15 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) local_irq_disable(); kvm_after_interrupt(vcpu); + /* + * Wait until after servicing IRQs to account guest time so that any + * ticks that occurred while running the guest are properly accounted + * to the guest. Waiting until IRQs are enabled degrades the accuracy + * of accounting via context tracking, but the loss of accuracy is + * acceptable for all known use cases. + */ + vtime_account_guest_exit(); + if (lapic_in_kernel(vcpu)) { s64 delta = vcpu->arch.apic->lapic_timer.advance_expire_delta; if (delta != S64_MIN) {