WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-ia64-devel

RE: [Xen-ia64-devel] Console problem on domU on tip?

To: "Xu, Anthony" <anthony.xu@xxxxxxxxx>, "Magenheimer, Dan \(HP Labs Fort Collins\)" <dan.magenheimer@xxxxxx>, <xen-ia64-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-ia64-devel] Console problem on domU on tip?
From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Fri, 16 Dec 2005 10:15:50 +0800
Delivery-date: Fri, 16 Dec 2005 02:17:45 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-ia64-devel-request@lists.xensource.com?subject=help>
List-id: Discussion of the ia64 port of Xen <xen-ia64-devel.lists.xensource.com>
List-post: <mailto:xen-ia64-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcYBELBGMu7ZHSeYRUaEav49mCDvgwAAVFMwAADLrDAAIbQEoAARHDxgAAFwgsA=
Thread-topic: [Xen-ia64-devel] Console problem on domU on tip?
>From: Xu, Anthony
>Sent: 2005年12月16日 9:54
>
>>Also, why panic if it fails?
>>

Panic is not required here, and we could just print out a warning message. 
Previously panic is kept there to help our debug in early stage.

>
>
>>Does the problem happen only on VTI?  Or both VTI and non-VTI on
>>split-cache machines?
>
>Sometimes, it makes domain0 crash at the very beginning of the domain0 boot
>process, especially on MP machine.
>
>
>Thanks
>-Anthony

One complement is, that problem definitely exists on new split-cache 
processors, for dom0/domU. For VTI domain, we have logic within device model to 
ensure consistence.

Thanks,
Kevin
>
>
>>-----Original Message-----
>>From: Magenheimer, Dan (HP Labs Fort Collins)
>[mailto:dan.magenheimer@xxxxxx]
>>Sent: 2005年12月16日 1:39
>>To: Tian, Kevin; xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>>Cc: Xu, Anthony
>>Subject: RE: [Xen-ia64-devel] Console problem on domU on tip?
>>
>>> >Is this code fragment necessary for VTI to boot domU
>>> >or is it OK to remove?
>>>
>>>     The comment is inaccurate and it should be domU. That I/D cache
>>> sync step is mandatory to boot domU on new IA64 processor which has
>>> split L2 I/D cache. If without such I/D cache sync, control
>>> panel loads
>>> domU's kernel image which only affects D side cache. If there're some
>>> stale entry on I-side cache within same range of dom0 image,
>>> people will
>>> see machine going weird.
>>
>>I don't understand... how can there be stale entries in the I-cache?
>>The instructions have just been written to memory (through D-cache)
>>and no instructions in this domain have yet been executed.
>>I do see that the D-cache needs to be flushed so that memory is
>>coherent but are there better ways to do that without a pal call?
>>
>>>     Normally I/D cache sync shouldn't force any problem. Possibly
>>> there's some problem with the pal calling code, like incorrect ITLB
>>> mapping for pal or similar issue...
>>
>>Although the ia64_pal_cache_flush routine is defined in linux's pal.h,
>>it doesn't appear to be used anywhere in Linux so there is no use
>>model to copy.  I suspect there is some use model for the call that
>>we don't understand, for example maybe it should only be called with
>>physical &progress?  It definitely fails every time on one of
>>my (newer) machines and disabling the pal call makes the problem
>>go away.
>>
>>> Though it's intermittent, please
>>> keep this code
>>> there for correctness.
>>
>>Since the call is definitely failing under some circumstances
>>that we don't understand, I'm inclined to at least put the code
>>in an #ifdef CONFIG_SPLIT_CACHE
>>
>>Does the problem happen only on VTI?  Or both VTI and non-VTI on
>>split-cache machines?
>>
>>Thanks,
>>Dan
>>
>>P.S. I tried Anthony's patch (which moves the PAL call after
>>new_thread()) but it still crashes.

_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel

<Prev in Thread] Current Thread [Next in Thread>