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 E2077C433ED for ; Sat, 8 May 2021 09:32:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFED861358 for ; Sat, 8 May 2021 09:32:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230393AbhEHJdO (ORCPT ); Sat, 8 May 2021 05:33:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229583AbhEHJdM (ORCPT ); Sat, 8 May 2021 05:33:12 -0400 Received: from mail-pl1-x62d.google.com (mail-pl1-x62d.google.com [IPv6:2607:f8b0:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98132C061756; Sat, 8 May 2021 02:32:10 -0700 (PDT) Received: by mail-pl1-x62d.google.com with SMTP id b21so6498435plz.0; Sat, 08 May 2021 02:32:10 -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=1CGHW9g1U7mxu/mVGb43UumaGiz2ve3vaE4gPvsroXY=; b=pbDNw1Fx99ba7QrZGEIm3/SSQPA+bqJOrtp8ZLb9V73V8MxilDw19X7PFvb6cmZHlr tWsyk85UfQdF1vdn/Gzb1CZITBpP0i/KxS2W/2wEL9L+l2I1kUagiHakVRr2SaxxnbEm QTu2kzhqPT6bab/UqOaOoLw4vMasOeqqHD7kX4VfKoZ1iM0xlIEsyO+L+Xsz4+0TiEKg 8YQhDFEbjSbSfWzYzsCfUkybNrPTk5djolvDN2iWu1z+nll5XaU+/17OvAjhbfTA62+v Hl5LOzFPTW0bvHLcqWx+SMDAVN1rasBs3Q5jSaJp/lbeclLW4QFCxLzvrFuKu+r3O7sM SI6g== 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=1CGHW9g1U7mxu/mVGb43UumaGiz2ve3vaE4gPvsroXY=; b=nx8kNBusuWfeiTqbEqLZ+J4E9UnFXKc95WDiOdop1r5NQhRmAwawxGDi6RuoUmmWd3 LUzV5w8/5lwEnBQsV0CK+mbtdjIUxx0sVfU5t3LpHTPG/LQbKCLv7/ENjHZNNAEW9GTj uK8818l/yQvKPxH4daMW6yJmJkO7/ZQRxObEB0W1FreSkkEQgBZMKHoIW3grDvp6DbWa oLKOdn4Txe9o0IMhT9prveN44ZrpOXDwFQfT9k7k5NlGm1ntfVFfDotbe6iPMWpOL1L3 Xg4LL1u9K6YPGVMjnKjKvsQzPtVHLpwGlX+oWhXg+gdpiLNIt6GhuBDEYCk6pSPZjFke /JDA== X-Gm-Message-State: AOAM530ndE7Xt/iTv/EeSdX5MI29FInSofknkn+YerdDL3Gaci5NJaAp 9qfSo+GxSV704inmSFxBtgO0wRR3Vq0= X-Google-Smtp-Source: ABdhPJy//+f7HmIzch4pMQ1TT6uDnh5IuVL+45PNnmpu/8oWSEAXNCv0ga9U3CCfGHrHzyAqD2BfwA== X-Received: by 2002:a17:902:bc88:b029:ee:7ef1:e770 with SMTP id bb8-20020a170902bc88b02900ee7ef1e770mr14621444plb.19.1620466329986; Sat, 08 May 2021 02:32:09 -0700 (PDT) Received: from localhost.localdomain ([103.7.29.6]) by smtp.googlemail.com with ESMTPSA id f3sm40437765pjo.3.2021.05.08.02.32.07 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 08 May 2021 02:32:09 -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 3/3] KVM: X86: Fix vCPU preempted state from guest point of view Date: Sat, 8 May 2021 17:31:50 +0800 Message-Id: <1620466310-8428-3-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1620466310-8428-1-git-send-email-wanpengli@tencent.com> References: <1620466310-8428-1-git-send-email-wanpengli@tencent.com> Precedence: bulk List-ID: X-Mailing-List: kvm@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 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) Cc: stable@vger.kernel.org Signed-off-by: Wanpeng Li --- arch/x86/kvm/x86.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c0244a6..c38e990 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3105,7 +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; -- 2.7.4