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 3C881C433B4 for ; Tue, 18 May 2021 12:02:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18CD36124C for ; Tue, 18 May 2021 12:02:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349012AbhERMDY (ORCPT ); Tue, 18 May 2021 08:03:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234375AbhERMC5 (ORCPT ); Tue, 18 May 2021 08:02:57 -0400 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE98AC061573; Tue, 18 May 2021 05:01:38 -0700 (PDT) Received: by mail-pf1-x429.google.com with SMTP id 22so6833731pfv.11; Tue, 18 May 2021 05:01:38 -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=ZeIi/gvUNym2Dd9YiXCf0AJ6fBKidFcXrnjVOMnupLUuz68CdlrtfW7q5h4nJIROaL TWXnzoNvpXjL+zgx3xqklTashGR+nM8dtmqHEYd6+4EVF13Cy6ZpX6/tws9rkD7dAlOA 2O4WmVYoYHPa/5omhQZUAT6lXRCI1IZ6H+QVRm208oFVL0GrXO0ZH5ppfkEV8row5IU4 2NgnNsAgTs/ITFePFDUNowhYlRCJTeUdjAuadljv0cqV/Kgo3tPXNIqfZOJqhnXgsI89 aa3jreh6+3yBGZMfNp/PE+zNFSlgy26UHE4lSTuxldVNNuORYEyqfksVeXY4pnHyX0Yc lVzQ== 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=ediIZu6qNP2n5peNx8wh2jQi3E+pEC7nOGfWCwWUJ0N34LT03dsYq2PQU6kE5ZxeDo Fq+kGmdc4vKiHNU+XAMFYfqBuLGutGRuKuFp0GdXEXk4oGUNIWsf45RmWr1uv88L2tiU 1kDhUkUjo7uU9jOeTpHUMixj55X1tr/dzWYIH9U3TTVr/GwWXiFLUOgQAUnd3gsJ3AcI gq99WHtKQvZx/3s19422/lGeXf7lGZFe67fUdBnfcnzNYDKYgdrF9W0m819cEW3ZF7IW LzuvX7RQiNcKFs32B6Aq/3kmsA9TL0KUMRj7lDd84i3EVw5U9Zs6k5StRi1pZsqdqWZx FfdQ== X-Gm-Message-State: AOAM531dCO72/icA8o2kYQVRGcszsBHpq8OeoyIDEYI1np6Wpt/dbFso LUWyIIjMXeM/ENBvHKqK4pele5X0IDY= X-Google-Smtp-Source: ABdhPJxcbPclLPPTmDzgEncZEZSD0AaWP/y/J2B3jrqQOaA8ZnYm4qZvxlrmL+hkSI63xUnGUyL7nA== X-Received: by 2002:a63:4d5c:: with SMTP id n28mr4700618pgl.436.1621339298356; Tue, 18 May 2021 05:01:38 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.53]) by smtp.googlemail.com with ESMTPSA id l20sm12757394pjq.38.2021.05.18.05.01.35 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 May 2021 05:01:37 -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 v4 3/5] KVM: X86: Fix vCPU preempted state from guest's point of view Date: Tue, 18 May 2021 05:00:33 -0700 Message-Id: <1621339235-11131-3-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1621339235-11131-1-git-send-email-wanpengli@tencent.com> References: <1621339235-11131-1-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