Re: [PATCH 11/11] nEPT: Provide the correct exit qualification upon EPT

[Jan Kiszka <jan.kiszka@siemens.com>]

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On 2013-05-02 08:59, Xu, Xinhao wrote:
> Hi, Jan
> Can you provide details of your test environment?

Pretty simple: Run a Linux 3.9(-rc5) kernel as L2 on top of the same
kernel with QEMU (git head at that time). I've attached the config.

Jan

> 
> -----Original Message-----
> From: Jan Kiszka [mailto:jan.kiszka@web.de] 
> Sent: Sunday, April 28, 2013 5:36 PM
> To: Xu, Xinhao
> Cc: Nakajima, Jun; kvm@vger.kernel.org
> Subject: Re: [PATCH 11/11] nEPT: Provide the correct exit qualification upon EPT
> 
> On 2013-04-27 08:42, Xu, Xinhao wrote:
>> From 2df72c1e8e3b167a6008ab11e2a68d734c68e425 Mon Sep 17 00:00:00 2001
>> From: Xinhao Xu <xinhao.xu@intel.com>
>> Date: Sat, 27 Apr 2013 05:45:49 +0800
>> Subject: [PATCH] nEPT: Check EPT misconfiguration while walking addr & 
>> move pte  check code to vmx.c
> 
> Please fix up the subject when posting a patch in reply to another one.
> 
>>
>> I add code to detect EPT misconfiguration and inject it to L1.
>> Now L1 can correctly go to ept_misconfig handler(instead of wrongly 
>> going to fast_page_fault), it will try to handle mmio page fault, if 
>> failed, it is a real ept misconfiguration.
>>
>> For scalability, Xiantao suggests me moving vendor specific code out 
>> from common code. In order to do this, I add new ops in kvm_mmu 
>> struct, check_tdp_pte, to provide an interface to check fault while 
>> walking address. The better way is to do fault detecting at here, but 
>> so far I just have checked ept misconfiguration. More patches will be 
>> added in future.
> 
> Seems there are some issues remaining. I can boot Linux as L2 when I remove this patch. When it's applied, L2 becomes pretty slow and eventually resets during kernel boot of L2. L1 remains stable.
> 
> Jan
> 
> 

-- 
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux

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