From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir.fraser@eu.citrix.com>
Subject: Re: Question about PV guest accessing /dev/mem
Date: Wed, 28 Jul 2010 07:49:14 +0100
Message-ID: <C875917A.1BCEF%keir.fraser@eu.citrix.com>
References: <41885A88D9043444B138491FB10E15420496C7E674@azsmsx506.amr.corp.intel.com>
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To: "Oehrlein, Scott" <scott.oehrlein@intel.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
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On 28/07/2010 02:37, "Oehrlein, Scott" <scott.oehrlein@intel.com> wrote:

> I can then read/write to the devices config space using logicaladdress. W=
hen
> using Xen=B9s PV functionality with pciback/pcifront to assign the device t=
o the
> guest on a platform without VT-d support, an attempt to use logicaladdres=
s
> results in the following error in ``xm dmesg=B9=B9:
> =20
> (XEN) mm.c:1747:d23 Bad L1 flags 800000
> =20
> Does this mean Xen=B9s mmu is not mapping gfn to mfn correctly? Or what is
> happening after the call to mmap that is different from native path?

I think that means the guest OS is trying to map a PTE with the NX bit set
when your processor does not support NX. Xen disallows that, and it would b=
e
a bug in the guest (Linux 2.6.34 in this case?).

 -- Keir