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 40479C4332F for ; Thu, 9 Dec 2021 17:57:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243044AbhLISA5 (ORCPT ); Thu, 9 Dec 2021 13:00:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237713AbhLISA4 (ORCPT ); Thu, 9 Dec 2021 13:00:56 -0500 Received: from mail-ed1-x535.google.com (mail-ed1-x535.google.com [IPv6:2a00:1450:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BF5AC061746; Thu, 9 Dec 2021 09:57:22 -0800 (PST) Received: by mail-ed1-x535.google.com with SMTP id t5so21799062edd.0; Thu, 09 Dec 2021 09:57:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=vqYJs8ulCPYB6TV0uKw95U9Qt8mnj6uUyMoCrLDmeno=; b=Y55T6pHryCo6jBHye2ztoPCjeRsE5RiCzDMV8dRa0nx+MQOx7nWHx8RV9xFvh+zsGP OqkQmM1I5YBgGoevUcszC4o3DBJrXQimSzQm7wGkLObHXsMLZR3G1lZ61wvcVnUrqq+3 mw+d+5Gzp6RYIMae0GQgiJkMK4r5D0Op34/tTe59+w0UhJ8M/UeFuQEiNmZNm//hA3yc us5xvHahEEsueud1DUpU946wRIGZ0wAGpyG+iBITENKzMHbbg9qDXUd/BlqVbC3sA4vk 988SciurOMCQWQmCF/NT5ViaDRKFl43XLipUpSeXJCQaV9ThaQ8qSi+Dxn6t5dV6YH/f 4ulQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:message-id:date:mime-version:user-agent :subject:content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=vqYJs8ulCPYB6TV0uKw95U9Qt8mnj6uUyMoCrLDmeno=; b=RL6j6mJAN9DFR6j/hEj2O+EhwYDSanjg+MhtFi2khRuiNJo8d8yRN2DChnwGLzlL4S j37jgFJqlT3LWf3sBo2sJtd7kB8iuqDl6d7eO5MwMXil+ODh4XVGvqXhIhK5R+uQnzAO 7bFNUDPFIA1UEersa8Jy39w6o6FYqO/5IuTyiytvYmbskcKek1Pob3nGCHhZfrC8e1HJ SXpohF0w+20SR5ZCNc9s0JX7PbAHghge4tFr7smKBfbU3IQMo3QVe3IVsXH6bWTb+b25 askE/Yr5kDgl4NhudxMCSnaKDplnGZ0kIXRLd+L6xSYynC8eStWvud87GpUJFg4y73Vm HKRQ== X-Gm-Message-State: AOAM533+8s28rlkubsAr/j9/YB8jU+b0RmeA34sY4brXduFNC6+VqqZm 0CKnWmJ0rEqNxzhq7MAGcUE= X-Google-Smtp-Source: ABdhPJyKTSLZGm8P+5u/1t09ws9SyWIvKZ/EiazfBaOngsVJioYhDnEGXuuObeyYEdUAs8uVj8UlLA== X-Received: by 2002:aa7:d941:: with SMTP id l1mr31320710eds.85.1639072507252; Thu, 09 Dec 2021 09:55:07 -0800 (PST) Received: from ?IPV6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.googlemail.com with ESMTPSA id g15sm275736ejt.10.2021.12.09.09.55.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 09 Dec 2021 09:55:06 -0800 (PST) Sender: Paolo Bonzini Message-ID: <51bb6e75-4f0a-e544-d2e4-ff23c5aa2f49@redhat.com> Date: Thu, 9 Dec 2021 18:55:05 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH] KVM: X86: Raise #GP when clearing CR0_PG in 64 bit mode Content-Language: en-US To: Lai Jiangshan , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Lai Jiangshan , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" References: <20211207095230.53437-1-jiangshanlai@gmail.com> From: Paolo Bonzini In-Reply-To: <20211207095230.53437-1-jiangshanlai@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/7/21 10:52, Lai Jiangshan wrote: > From: Lai Jiangshan > > In the SDM: > If the logical processor is in 64-bit mode or if CR4.PCIDE = 1, an > attempt to clear CR0.PG causes a general-protection exception (#GP). > Software should transition to compatibility mode and clear CR4.PCIDE > before attempting to disable paging. > > Signed-off-by: Lai Jiangshan > --- > 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 00f5b2b82909..78c40ac3b197 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -906,7 +906,8 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) > !load_pdptrs(vcpu, kvm_read_cr3(vcpu))) > return 1; > > - if (!(cr0 & X86_CR0_PG) && kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE)) > + if (!(cr0 & X86_CR0_PG) && > + (is_64_bit_mode(vcpu) || kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE))) > return 1; > > static_call(kvm_x86_set_cr0)(vcpu, cr0); > Queued, thanks. Paolo