From: Wei Wang <wei.wang2@amd.com>
To: Sander Eikelenboom <linux@eikelenboom.it>
Cc: Keir Fraser <keir.xen@gmail.com>,
Santosh Jodh <Santosh.Jodh@citrix.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: Using debug-key 'o: Dump IOMMU p2m table, locks up machine
Date: Mon, 3 Sep 2012 17:20:55 +0200 [thread overview]
Message-ID: <5044CAD7.8030800@amd.com> (raw)
In-Reply-To: <217459398.20120902171441@eikelenboom.it>
On 09/02/2012 05:14 PM, Sander Eikelenboom wrote:
> Sunday, September 2, 2012, 4:58:58 PM, you wrote:
>
>> On 02/09/2012 09:43, "Sander Eikelenboom"<linux@eikelenboom.it> wrote:
>
>>>> Quite simply, there likely needs to be more tracing on the IOMMU fault path.
>>>> That's a separate concern from your keyhandler of course, but just saying
>>>> I'd be looking for the former rather than the latter, for diagnosing
>>>> Sander's bug.
>>>
>>> Are there any printk's I could add to get more relevant info about the AMD-Vi:
>>> IO_PAGE_FAULT ?
>
>> No really straightforward one. I think we need a per-IOMMU-type handler to
>> walk the IOMMU page table for a given virtual address, and dump every
>> page-table-entry on the path. Like an IOMMU version of show_page_walk().
>> Personally I would suspect this is more useful than the dump-everything
>> handlers: just give a *full* *detailed* walk for the actually interesting
>> virtual address (the one faulted on).
>
>>> I have attached new output from xl dmesg, this time with iommu=debug on (the
>>> option changed from 4.1 to 4.2).
>
>> Not easy to glean any more from that, without extra tracing such as
>> described above, and/or digging into the guest to find what driver-side
>> actions are causing the faults.
>
> OK, too bad!
> With xen 4.1 i haven't experienced those page faults, but a diff between /xen/drivers/passthrough/amd in both trees show quite some changes :(
Did you also update xen tools accordingly? Sometime I also saw a few
IO_PAGE_FAULTs came from nic if my tools version and HV version did not
match. But using recent 4.2 and corresponding xl, my tests went well.
BTW: You could also try iommu=no-sharept to see if it helps.
Thanks,
Wei
>> -- Keir
>
>>>
>>>
>>>> -- Keir
>>>
>
>
>
>
>
>
next prev parent reply other threads:[~2012-09-03 15:20 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-31 21:45 Using debug-key 'o: Dump IOMMU p2m table, locks up machine Sander Eikelenboom
2012-08-31 22:24 ` Santosh Jodh
2012-08-31 22:42 ` Sander Eikelenboom
2012-08-31 22:57 ` Santosh Jodh
2012-08-31 23:16 ` Sander Eikelenboom
2012-08-31 23:58 ` Santosh Jodh
2012-09-01 0:42 ` Santosh Jodh
2012-09-03 8:14 ` Jan Beulich
2012-09-01 2:01 ` Keir Fraser
2012-09-01 17:03 ` Santosh Jodh
2012-09-01 19:13 ` Keir Fraser
2012-09-02 2:08 ` Santosh Jodh
2012-09-02 7:13 ` Keir Fraser
2012-09-02 7:19 ` Keir Fraser
2012-09-02 8:43 ` Sander Eikelenboom
2012-09-02 14:58 ` Keir Fraser
2012-09-02 15:14 ` Sander Eikelenboom
2012-09-03 15:20 ` Wei Wang [this message]
2012-09-04 8:21 ` Sander Eikelenboom
2012-09-04 16:43 ` Sander Eikelenboom
2012-09-05 10:14 ` Jan Beulich
2012-09-05 10:25 ` Sander Eikelenboom
2012-09-05 10:40 ` Jan Beulich
2012-09-05 10:48 ` Sander Eikelenboom
2012-09-05 11:41 ` Jan Beulich
2012-09-05 12:11 ` Sander Eikelenboom
2012-09-05 14:15 ` Wei Wang
2012-09-05 15:05 ` Jan Beulich
2012-09-05 12:48 ` Wei Wang
2012-09-05 12:30 ` Wei Wang
2012-09-03 8:21 ` Jan Beulich
2012-09-03 8:33 ` Sander Eikelenboom
2012-09-03 9:05 ` Jan Beulich
2012-09-04 7:08 ` Sander Eikelenboom
2012-09-04 7:46 ` Jan Beulich
2012-09-04 8:13 ` Sander Eikelenboom
2012-09-04 9:26 ` Jan Beulich
2012-10-02 20:09 ` Konrad Rzeszutek Wilk
2012-10-03 13:12 ` Jan Beulich
2012-10-02 20:54 ` Matt Wilson
2012-09-20 8:08 ` Jan Beulich
2012-09-28 14:08 ` Sander Eikelenboom
2012-09-28 21:26 ` Jeremy Fitzhardinge
2012-10-02 20:08 ` Konrad Rzeszutek Wilk
2012-09-02 7:42 ` Keir Fraser
2012-09-04 6:35 ` Jan Beulich
2012-09-04 6:52 ` Sander Eikelenboom
2012-09-04 7:01 ` Keir Fraser
2012-09-04 6:59 ` Keir Fraser
2012-09-04 7:55 ` Jan Beulich
2012-09-04 8:04 ` Keir Fraser
2012-09-04 8:11 ` Keir Fraser
2012-09-04 8:20 ` Sander Eikelenboom
2012-09-04 8:38 ` Jan Beulich
2012-09-04 8:54 ` Keir Fraser
2012-09-04 9:40 ` Jan Beulich
2012-09-04 13:29 ` Andrew Cooper
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