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From: "Li, Xin" <xin.li@intel.com>
To: Keir Fraser <keir.xen@gmail.com>,
	"Yang, Wei Y" <wei.y.yang@intel.com>,
	"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: RE: [Patch] Enable SMEP CPU feature support for XEN itself
Date: Thu, 2 Jun 2011 06:52:38 +0800	[thread overview]
Message-ID: <FC2FB65B4D919844ADE4BE3C2BB739AD5AB183C0@shsmsx501.ccr.corp.intel.com> (raw)
In-Reply-To: <CA0C630E.1B68C%keir.xen@gmail.com>

> >>> and kills a pv guest triggering SMEP fault.
> >>
> >> Should only occur when the guest kernel triggers the SMEP.
> >
> > According to code base size, it's much easier for malicious applications to
> > explore
> > security holes in kernel.  But unluckily SMEP doesn't apply to the ring 3
> > where
> > x86_64 pv kernel runs on.  It's wiser to use HVM :)
> 
> Yep, but 32-bit guests can still benefit.

Can we know a guest will be 32bit or 64bit before it boots?
Code will be like
	xc_pv_cpuid_policy()
	{
        case 7, 0:
            if ( 64 bit pv guest )
                 disallow smep;
	}
I don't know if we can distinguish that when creating guest.
Thanks!
-Xin

  reply	other threads:[~2011-06-01 22:52 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-01 13:20 [Patch] Enable SMEP CPU feature support for XEN itself Yang, Wei Y
2011-06-01 14:34 ` Keir Fraser
2011-06-01 14:50   ` Li, Xin
2011-06-01 15:17 ` Jan Beulich
2011-06-01 15:23   ` Ian Campbell
2011-06-02  4:20   ` Li, Xin
2011-06-02  7:45   ` Li, Xin
2011-06-01 15:26 ` Keir Fraser
2011-06-01 16:15   ` Li, Xin
2011-06-01 20:43     ` Keir Fraser
2011-06-01 22:52       ` Li, Xin [this message]
2011-06-02  6:25         ` Keir Fraser
2011-06-02 10:07           ` Li, Xin
2011-06-02 13:29 Jan Beulich
2011-06-02 14:36 ` Li, Xin
2011-06-02 15:05   ` Li, Xin
2011-06-02 19:24   ` Keir Fraser
2011-06-02 22:49     ` Li, Xin
2011-06-03 11:54       ` Li, Xin
2011-06-03 12:34         ` Keir Fraser

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