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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 2E52BC433ED for ; Mon, 17 May 2021 14:01:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F52061355 for ; Mon, 17 May 2021 14:01:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237678AbhEQOCz (ORCPT ); Mon, 17 May 2021 10:02:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237574AbhEQOCn (ORCPT ); Mon, 17 May 2021 10:02:43 -0400 Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2ACE7C061573; Mon, 17 May 2021 07:01:27 -0700 (PDT) Received: by mail-pj1-x1033.google.com with SMTP id j6-20020a17090adc86b02900cbfe6f2c96so3765502pjv.1; Mon, 17 May 2021 07:01:27 -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; bh=/2GPjTLQ/YR+wnuKsns5/Hi1QLal2y1jDQCRlyJhbRk=; b=m78vKY4Ils3Zka2LHxaL7/u8+Ux75+b2P5JcA51NnA/mOemelC6vljDXQ+wiyyhvCj JcjTebx//vYgWfEddx+4wvQUX1l7NeyFbhAH3MOb85xrYr/KeMFbUGJY7jhAj3QsUWqa Z6idJdQmlCCZ11B9YyUIFVhbybDaPahq0a8NVz/nVkumfpLeikq53mrI198nC7ujuGCT Cogu7jTwppj9IZ3sh48PkLyHT+42fOsBnPkjyLMzJmam9bpe9gqLeEqpZ1l08W//h4XJ 4UAwQtoURr7VZfMLg2KuYO2WNphH7/SD7nw9RoaemRDr4C21vW2+X2i7LfF1/mWAclO7 qSRg== 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; bh=/2GPjTLQ/YR+wnuKsns5/Hi1QLal2y1jDQCRlyJhbRk=; b=k6G5HSWZBpeFC3c5o5B8zeDl5S9l3gVnt7spPcyYBMgnbAkksYo43tYzdc2fnfxdn5 wRWW+CAEacRwk9GDLNlU2E4TLNwk4A3bCz9pCQF6rgjL+25Wm6oWyOl0QxlE2xBO18jX TvTEXwTuhneyEjEh3IFvUNVe/2+G9vZr8u9KXCaGOJ4OB9pM2sxys25V1p8zDIOmf4u1 sM9lSf17x8jZJKbSS5bR3hhXJ5uu3eLxqC8UZhNaTRY37YMx5AtoGH9t+h/cbX3trrA+ Avusii+NSLMbM0jDNcmI9X6kABaGQzVNyEbu+kX2bZa5rx86cv67nvHDCnpmEK+zfscG hwJg== X-Gm-Message-State: AOAM5333rs8yO9h5ZkTyvepiYM9dfvDFTLP6LYe+80fNK6oOUMY3S9JU XrY4ToHGgCk78aouwiUBmW0fMRnO/tM= X-Google-Smtp-Source: ABdhPJwaT9yOEYd0kc9RCcyNp41kW9zpGoSd03Lqy76hsnwtT1jmF+q8DlO5M2OCw0rdT+rzvYgcMA== X-Received: by 2002:a17:90a:4a0e:: with SMTP id e14mr58581pjh.209.1621260086511; Mon, 17 May 2021 07:01:26 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.61]) by smtp.googlemail.com with ESMTPSA id k10sm3074229pfu.175.2021.05.17.07.01.23 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 17 May 2021 07:01:26 -0700 (PDT) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , stable@vger.kernel.org Subject: [PATCH v3 3/5] KVM: X86: Fix vCPU preempted state from guest's point of view Date: Mon, 17 May 2021 07:00:26 -0700 Message-Id: <1621260028-6467-3-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1621260028-6467-1-git-send-email-wanpengli@tencent.com> References: <1621260028-6467-1-git-send-email-wanpengli@tencent.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li Commit 66570e966dd9 (kvm: x86: only provide PV features if enabled in guest's CPUID) avoids to access pv tlb shootdown host side logic when this pv feature is not exposed to guest, however, kvm_steal_time.preempted not only leveraged by pv tlb shootdown logic but also mitigate the lock holder preemption issue. >From guest's point of view, vCPU is always preempted since we lose the reset of kvm_steal_time.preempted before vmentry if pv tlb shootdown feature is not exposed. This patch fixes it by clearing kvm_steal_time.preempted before vmentry. Fixes: 66570e966dd9 (kvm: x86: only provide PV features if enabled in guest's CPUID) Reviewed-by: Sean Christopherson Cc: stable@vger.kernel.org Signed-off-by: Wanpeng Li --- v1 -> v2: * add curly braces arch/x86/kvm/x86.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index dfb7c320581f..bed7b5348c0e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3105,6 +3105,8 @@ static void record_steal_time(struct kvm_vcpu *vcpu) st->preempted & KVM_VCPU_FLUSH_TLB); if (xchg(&st->preempted, 0) & KVM_VCPU_FLUSH_TLB) kvm_vcpu_flush_tlb_guest(vcpu); + } else { + st->preempted = 0; } vcpu->arch.st.preempted = 0; -- 2.25.1