RE: [Xen-devel] Critical bug: VT-d fault causes disk corruption or Dom0 kernel panic.

["Kay, Allen M" <allen.m.kay@xxxxxxxxx>]

I have not figured out why this is the problem yet but I know comment it out 
makes the problem go away.  Leaving tboot_in_range() in does not cause this 
problem.

Allen

-----Original Message-----
From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx] 
Sent: Friday, January 23, 2009 12:34 AM
To: Kay, Allen M; Li, Xin; Li, Haicheng; 'xen-devel@xxxxxxxxxxxxxxxxxxx'
Subject: Re: [Xen-devel] Critical bug: VT-d fault causes disk corruption or 
Dom0 kernel panic.

Are you sure that is the problem? The xen_in_range() change should make the
dom0 VT-d table more permissive, and hence if anything less likely to
experience VT-d faults. Also it wouldn't seem to explain problems for HVM
guest passthrough.

 -- Keir

On 23/01/2009 01:01, "Kay, Allen M" <allen.m.kay@xxxxxxxxx> wrote:

> Looks like the problem is caused by xen_in_range() call in
> vtd/iommu.c/intel_iommu_domain_init().  Definition of xen_in_range() was
> changed as part of the heap patch.
> 
> I'm looking into change intel_iommu_domain_init() to just map pages in
> dom0->page_list.  However this looks to be more complicated as d->page_list is
> not initialized at this stage of the boot yet.
> 
> Allen
> 
> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Keir Fraser
> Sent: Thursday, January 22, 2009 1:23 AM
> To: Li, Xin; Li, Haicheng; 'xen-devel@xxxxxxxxxxxxxxxxxxx'
> Subject: Re: [Xen-devel] Critical bug: VT-d fault causes disk corruption or
> Dom0 kernel panic.
> 
> Mmm well not really. :-)
> 
> Is there any assumption in the VT-d setup about preventing access to the Xen
> heap, and could that be broken?
> 
> Perhaps the VT-d pagetables are broken causing bad DMAs leading to data
> corruption and bad command packets?
> 
>  -- Keir
> 
> On 22/01/2009 08:58, "Li, Xin" <xin.li@xxxxxxxxx> wrote:
> 
>> We are looking into the issue too. If you have any idea on how it's caused,
>> please tell us :-)
>> Thanks!
>> -Xin
>> 
>>> -----Original Message-----
>>> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>>> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Keir Fraser
>>> Sent: Thursday, January 22, 2009 3:40 PM
>>> To: Li, Haicheng; 'xen-devel@xxxxxxxxxxxxxxxxxxx'
>>> Subject: Re: [Xen-devel] Critical bug: VT-d fault causes disk corruption or
>>> Dom0
>>> kernel panic.
>>> 
>>> Thanks,
>>> 
>>> I haven't seen any problems outside of VT-d since c/s 19057, btw.
>>> 
>>> -- Keir
>>> 
>>> On 22/01/2009 03:42, "Li, Haicheng" <haicheng.li@xxxxxxxxx> wrote:
>>> 
>>>> All,
>>>> 
>>>> We met several system failures on different hardware platforms, which are
>>>> all
>>>> caused by VT-d fault.
>>>> err 1: disk is corrupted by VT-d fault on SATA.
>>>> err 2: Dom0 kernel panics at booting, which is caused VT-d fault on UHCI.
>>>> err 3, Dom0 complains disk errors while creating HVM guests.
>>>> 
>>>> The culprit would be changeset 19054 "x86_64: Remove statically-partitioned
>>>> Xen heap.".
>>>> 
>>>> Detailed error logs can be found via BZ#,
>>>> http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=1409.
>>>> 
>>>> 
>>>> -haicheng
>>>> _______________________________________________
>>>> Xen-devel mailing list
>>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>>> http://lists.xensource.com/xen-devel
>>> 
>>> 
>>> 
>>> _______________________________________________
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>>> http://lists.xensource.com/xen-devel
> 
> 
> 
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