From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] KVM: VMX: Fix 32bit Windows blue screen with EPT Date: Thu, 30 Dec 2010 11:14:23 +0200 Message-ID: <4D1C4D6F.7030707@redhat.com> References: <1293698159-30452-1-git-send-email-sheng@linux.intel.com> <4D1C4970.9000409@redhat.com> <201012301705.28771.sheng@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org To: Sheng Yang Return-path: Received: from mx1.redhat.com ([209.132.183.28]:13205 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750993Ab0L3JO1 (ORCPT ); Thu, 30 Dec 2010 04:14:27 -0500 In-Reply-To: <201012301705.28771.sheng@linux.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On 12/30/2010 11:05 AM, Sheng Yang wrote: > > > > > if (!(cr0& X86_CR0_PG)) { > > > > > > /* From paging/starting to nonpaging */ > > > vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, > > > > > > @@ -1937,11 +1936,8 @@ static void ept_update_paging_mode_cr0(unsigned > > > long *hw_cr0, > > > > > > vmcs_read32(CPU_BASED_VM_EXEC_CONTROL)& > > > > > > ~(CPU_BASED_CR3_LOAD_EXITING | > > > > > > CPU_BASED_CR3_STORE_EXITING)); > > > > > > - /* Must fetch cr3 before updating cr0 */ > > > - cr3 = kvm_read_cr3(vcpu); > > > > > > vcpu->arch.cr0 = cr0; > > > vmx_set_cr4(vcpu, kvm_read_cr4(vcpu)); > > > > > > - vmx_set_cr3(vcpu, cr3); > > > > This is indeed bogus. But what ensures that we'll have the correct > > GUEST_CR3 after enabling paging? > > In fact I don't understand why we need this line. All modification is for CR3 > reading, why we need to set hardware CR3 again? It should be the same as when we > don't have CR3 accessor I think. when cr0.pg=0 then we set GUEST_CR3=identity_pagetable. We don't want that when we we switch to paging mode. -- error compiling committee.c: too many arguments to function