RE: [Xen-devel] Win2003 got blue Screen when ballooning with serial out put: "Iomem mapping not permitted"

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

If the frontend GPL PV storport driver is not ignoring block write failures in 
crashdump mode then you are unlikely the get a good dump from the ballooned 
down VM.
As for the original crash, I guess the balloon driver is just not handling the 
populate hypercall failure gracefully.

  Paul 

> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-
> bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of tinnycloud
> Sent: 17 December 2010 03:24
> To: Steven Smith; xen-devel@xxxxxxxxxxxxxxxxxxx
> Cc: james.harper@xxxxxxxxxxxxxxxx; Keir Fraser; JBeulich@xxxxxxxxxx
> Subject: [Xen-devel] Win2003 got blue Screen when ballooning with
> serial out put: "Iomem mapping not permitted"
> 
> Hi Steven:
> 
>       I was trying to make use of balloon driver on my win2003 HVM
> Guests,
> but confront a Guest crash problem with blue screen.
>       The serial output is much like
>       (XEN)grant_table.c:555:d0 Iomem mapping not permitted
> ffffffffffffffff
> 
>       My pvdriver changeset is 823. From
> http://xenbits.xensource.com/ext/win-pvdrivers.hg
>       Xen is 4.0.0
> 
>       I've done quite a lot experiments to locate the crash, and
> finally
> make it easy to reproduce.
>       Here is the situation:
> 
>       1) Start several Win2003 Guest with 2G memory to occupy host
> memory
> till from xm info | grep free to see xen has only almost 3G memory
>       2) Start another Guest with 2G memory, say domain X, and set
> its
> target to be 512M, after balloon, dom X will has only 512M, and xen
> has 2.5G
> memory
>       3) Start another Guest with 2G memory, then xen will have
> only 0.5G
> memory left
>       4) At this time, I set the domain X target to 2G (use
> xenstore-write
> /local/domain/x/memory/target 2097152)
>     5) domain X got blue screen at once. With code says 0x0000007f
> (0x0000000d, 0x00000000, 0x00000000, 0x00000000)"
> 
>       So, in short, when a domain wants more memory, it deflates
> its
> balloon, but if Xen doesn't enough memory, the domain will crash.
> 
>       I've go through
> http://lists.xensource.com/archives/html/xen-devel/2010-
> 01/msg01230.html
> 
> http://lists.xensource.com/archives/html/xen-devel/2010-
> 02/msg00074.html
> 
>       it looks like the crash is because windows crash dumper go
> through
> those balloon out pages
>       and from the discuss it would be harmless, but why I got this
> crash?
> 
>       Could you kindly offer me some help, thanks.
> 
> 
> 
> 
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> http://lists.xensource.com/xen-devel

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