re: Win2003 got blue Screen when ballooning with serial out put: "Iomem mapping not permitted"

[tinnycloud <tinnycloud@hotmail.com>]

Hi Paul:

	You are right. Thanks. 

	From the code PV driver, the exception handle is not finished by
James.

        KdPrint((__DRIVER_NAME "     Calling
HYPERVISOR_memory_op(XENMEM_populate_physmap) - pfn_count = %d\n",
pfn_count));
        ret = HYPERVISOR_memory_op(xpdd, XENMEM_populate_physmap,
&reservation);
        ExFreePoolWithTag(pfns, XENPCI_POOL_TAG);
        KdPrint((__DRIVER_NAME "     populated %d pages\n", ret));
        /* TODO: what do we do if less than the required number of pages
were populated??? can this happen??? *


	I will first try to implement myself.
	Also, that would be great appreciation if someone could offer this
patch. 


-----mail-----
: Paul Durrant [mailto:Paul.Durrant@citrix.com] 
sent: 2010年12月17日 16:53
to: tinnycloud; Steven Smith; xen-devel@lists.xensource.com
cc: james.harper@bendigoit.com.au; Keir Fraser; JBeulich@novell.com
Subject: RE: [Xen-devel] Win2003 got blue Screen when ballooning with serial
out put: "Iomem mapping not permitted"

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@lists.xensource.com [mailto:xen-devel-
> bounces@lists.xensource.com] On Behalf Of tinnycloud
> Sent: 17 December 2010 03:24
> To: Steven Smith; xen-devel@lists.xensource.com
> Cc: james.harper@bendigoit.com.au; Keir Fraser; JBeulich@novell.com
> 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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