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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5178CCCA47B for ; Sun, 5 Jun 2022 06:43:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348947AbiFEGnH (ORCPT ); Sun, 5 Jun 2022 02:43:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243907AbiFEGnA (ORCPT ); Sun, 5 Jun 2022 02:43:00 -0400 Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EFBE29805; Sat, 4 Jun 2022 23:42:56 -0700 (PDT) Received: by mail-pf1-x42a.google.com with SMTP id x4so1768343pfj.10; Sat, 04 Jun 2022 23:42:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=KM1oikz+Ia9mBiSM3+pw9WjtCt1EQ9hMQl48+WeL5cM=; b=HX8EfDf5WIq4AlYOacnyiqpv687wfE7clq7qblX2gZCKD/SJjyRVEpsfdmEE5hN/dx GRa3nOiWAHG1Qg50NUnkvf+jgvHXyiCvP0j/toJmLOfbbYTw7KMI4aXADgSZZ0EMPGLS 8K+s0TrmN5QbiuPEMix7EiyfHFT0yCqcfEbup9cp87hzCUUUcSXdDlVyZt1owQIKruug sTslzmaP3akqW43NdPrGlxKHheK0Jpmn7Qt4SEPMo+VvW6wqtpgE34ClnOjzCuWYPEyB 8iXFKONQFTKMCnGoBTScxRc+yLVPgUIY4QTQh0Zyh/rHoKwyyfJnYLS/q5VVJbejr9+E KFmg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=KM1oikz+Ia9mBiSM3+pw9WjtCt1EQ9hMQl48+WeL5cM=; b=GKT+8sPSbgFk1ZYdLa8mWZmEqvqFzRddqrqKTwDq8CtB68+6k63fwtNuEoOby1dFGa Lyfso9Z2tR4uFDTZ621009YaBxMyf9gO6edFVBkUzCeeBWreru9SocP969jvnoSDgpX3 t/D9a+qKDGWtwWfki2Eq3AM7pxdGQ3WVpOjqAP25JIbJzMaYhA6PYZlqEXTou2TwVZ1k buJkRjIPb95fMaJusL+ACq2VQOCULrtnWU3ziImAiYOoWtDy28xdmcWeAiHvlsZbAjek +nqHAQP8AnRf2l/mrOz1DbV+0YB0vexrWjWRbDERPnJe58pDKc2ZDoEN++ZFO3vUkpn/ z/gg== X-Gm-Message-State: AOAM5318vT9O0Q1R4sJ2D/dbKItX2RytAO+QTCcqp2ffxeVrn/TeTOWp JMvYSEMKIsr8zXZzcymRkaEFb0LLXwk= X-Google-Smtp-Source: ABdhPJxydESjX02nx0dTvWq2uEG82KGX3cWEuD45WHQtRyWrMfukHWuo2zgk70Nmo57dm2nNQYCXVA== X-Received: by 2002:a05:6a00:2293:b0:51b:f02e:de32 with SMTP id f19-20020a056a00229300b0051bf02ede32mr7524558pfe.17.1654411375583; Sat, 04 Jun 2022 23:42:55 -0700 (PDT) Received: from localhost ([198.11.178.15]) by smtp.gmail.com with ESMTPSA id q15-20020a170902eb8f00b0015e8d4eb25asm8059385plg.164.2022.06.04.23.42.54 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 04 Jun 2022 23:42:55 -0700 (PDT) From: Lai Jiangshan To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Maxim Levitsky , Lai Jiangshan Subject: [PATCH 01/12] KVM: X86/MMU: Warn if sp->unsync_children > 0 in link_shadow_page() Date: Sun, 5 Jun 2022 14:43:31 +0800 Message-Id: <20220605064342.309219-2-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20220605064342.309219-1-jiangshanlai@gmail.com> References: <20220605064342.309219-1-jiangshanlai@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lai Jiangshan The check for sp->unsync_children in link_shadow_page() can be removed since FNAME(fetch) ensures it is zero. (@sp is direct when link_shadow_page() is called from other places, which also means sp->unsync_children is zero.) link_shadow_page() is not a fast path, check it and warn instead. Signed-off-by: Lai Jiangshan --- arch/x86/kvm/mmu/mmu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 086f32dffdbe..f61416818116 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2197,7 +2197,13 @@ static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, mmu_page_add_parent_pte(vcpu, sp, sptep); - if (sp->unsync_children || sp->unsync) + /* + * Propagate the unsync bit when sp->unsync. + * + * The caller ensures the sp is synced when it has unsync children, + * so sp->unsync_children must be zero. See FNAME(fetch). + */ + if (sp->unsync || WARN_ON_ONCE(sp->unsync_children)) mark_unsync(sptep); } -- 2.19.1.6.gb485710b