From: Keir Fraser <keir.xen@gmail.com>
To: "Xu, Dongxiao" <dongxiao.xu@intel.com>, Tim Deegan <tim@xen.org>
Cc: "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH] VMX: disable SMEP feature when guest is in non-paging mode
Date: Wed, 30 Jan 2013 17:11:51 -0800 [thread overview]
Message-ID: <CD2F04D7.4B2B3%keir.xen@gmail.com> (raw)
In-Reply-To: <40776A41FC278F40B59438AD47D147A90FF0A622@SHSMSX102.ccr.corp.intel.com>
On 30/01/2013 16:56, "Xu, Dongxiao" <dongxiao.xu@intel.com> wrote:
>>> Shouldn't this be handled on CR0 writes as well as CR4? The SMEP bit of
>>> hw_cr[4] ought to be cleared and set whenever CR0_PG is changed.
>>
>> That's what I would expect too.
>
> In the case 0 (CR0 update) in vmx_update_guest_cr(), it will call
> vmx_update_guest_cr(v, 4) to adjust CR4 related bits if certain bits (PG, PE)
> in CR0 changed.
Good point!
In fact we can make that cr4 update unconditional and simplify the cr0
handling a bit more.
-- Keir
next prev parent reply other threads:[~2013-01-31 1:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-30 9:26 [PATCH] VMX: disable SMEP feature when guest is in non-paging mode dongxiao.xu
2013-01-30 17:54 ` Tim Deegan
2013-01-30 18:26 ` Keir Fraser
2013-01-31 0:56 ` Xu, Dongxiao
2013-01-31 1:11 ` Keir Fraser [this message]
2013-01-31 1:28 ` Xu, Dongxiao
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