Re: [Xen-devel] Using debug-key 'o: Dump IOMMU p2m table, locks up machine

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Saturday, September 1, 2012, 12:57:45 AM, you wrote:

> The dump should complete - would be curious to see how long it takes on 
> serial console. What baudrate is the console running at?

I think for ages, this part seems only to cover a bit of the first of 3 pv 
guests which have devices passed through.
38400

And i wonder if the information is very valuable, gfn == mfn for every line ... 
at an increment of 1 ...
Perhaps a uhmmm more compact way of getting the interesting data would be handy 
?
Or is this the intended output ?

> The code does allow processing of pending softirqs quite frequently. I am not 
> sure why you are still seeing SATA errors.

The machine is completely unresponsive in every way.

And using it with "xl debug-keys o" is never going to work i guess, since the 
information flood is far larger than "xl dmesg" keeps ?



>> -----Original Message-----
>> From: Sander Eikelenboom [mailto:linux@xxxxxxxxxxxxxx]
>> Sent: Friday, August 31, 2012 3:43 PM
>> To: Santosh Jodh
>> Cc: wei.wang2@xxxxxxx; xen-devel@xxxxxxxxxxxxx
>> Subject: Re: Using debug-key 'o: Dump IOMMU p2m table, locks up machine
>> 
>> 
>> Saturday, September 1, 2012, 12:24:32 AM, you wrote:
>> 
>> > Depending on how many VMs you have and the size of the IOMMU p2m
>> table, it can take a while. It should not be infinite though.
>> 
>> > How many VMs do you have running?
>> 
>> 15
>> 
>> > Can you please send the serial output when you press 'o'?
>> 
>> Attached, to the end you will see the s-ata errors coming through while the
>> dump still runs.
>> This is not a complete dump, only a few minutes after which i did a hard
>> reset.
>> 
>> > Santosh
>> 
>> >> -----Original Message-----
>> >> From: Sander Eikelenboom [mailto:linux@xxxxxxxxxxxxxx]
>> >> Sent: Friday, August 31, 2012 2:45 PM
>> >> To: Santosh Jodh; wei.wang2@xxxxxxx
>> >> Cc: xen-devel@xxxxxxxxxxxxx
>> >> Subject: Using debug-key 'o: Dump IOMMU p2m table, locks up machine
>> >>
>> >>
>> >> I was trying to use the 'o' debug key to make a bug report about an "AMD-
>> Vi:
>> >> IO_PAGE_FAULT".
>> >>
>> >> The result:
>> >> - When using "xl debug-keys o", the machine seems in a infinite loop,
>> >> can hardly login, eventually resulting in a kernel RCU stall and complete
>> lockup.
>> >> - When using serial console: I get a infinite stream of "gfn:  mfn: "
>> >> lines, mean while on the normal console, S-ATA devices are starting to
>> give errors.
>> >>
>> >> So either option trashes the machine, other debug-keys work fine.
>> >>
>> >> Machine has a 890-fx chipset and AMD phenom x6 proc.
>> >>
>> >> xl dmesg with bootup and output from some other debug-keys is
>> attached.
>> >>
>> >> --
>> >>
>> >> Sander
>> 
>> 
>> 
>> 
>> --
>> Best regards,
>>  Sander                            mailto:linux@xxxxxxxxxxxxxx




-- 
Best regards,
 Sander                            mailto:linux@xxxxxxxxxxxxxx


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