From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: KVM: MMU: handle invalid root_hpa at __direct_map
Date: Fri, 20 Dec 2013 19:22:57 +0100
Message-ID: <52B48B01.5060706@redhat.com>
References: <20131219172850.GA22588@amt.cnet>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Cc: kvm-devel <kvm@vger.kernel.org>,
	Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from mx1.redhat.com ([209.132.183.28]:45136 "EHLO mx1.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1753753Ab3LTSYC (ORCPT <rfc822;kvm@vger.kernel.org>);
	Fri, 20 Dec 2013 13:24:02 -0500
In-Reply-To: <20131219172850.GA22588@amt.cnet>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

Il 19/12/2013 18:28, Marcelo Tosatti ha scritto:
> 
> It is possible for __direct_map to be called on invalid root_hpa
> (-1), two examples:
> 
> 1) try_async_pf -> can_do_async_pf
>     -> vmx_interrupt_allowed -> nested_vmx_vmexit
> 2) vmx_handle_exit -> vmx_interrupt_allowed -> nested_vmx_vmexit
> 
> Then to load_vmcs12_host_state and kvm_mmu_reset_context.
> 
> Check for this possibility, let fault exception be regenerated.
> 
> BZ: https://bugzilla.redhat.com/show_bug.cgi?id=924916
> 
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> 
> 
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 40772ef..31a5702 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -2659,6 +2659,9 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
>  	int emulate = 0;
>  	gfn_t pseudo_gfn;
>  
> +	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
> +		return 0;
> +
>  	for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
>  		if (iterator.level == level) {
>  			mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,
> 

Applied to queue, thanks.

Paolo