Re: [Xen-devel] HVM support for e820_host (Was: Bug: Limitation of <=2GB RAM in domU persists with 4.3.0)

[Gordan Bobic <gordan@xxxxxxxxxx>]

OK, I have done some preliminary testing. Details below.

On 09/04/2013 02:11 PM, Gordan Bobic wrote:
> I have this at the point where it actually builds.
> Otherwise completely untested (will do that later today).
>
> Attached are:
>
> 1) libxl patch
> Modified from the original patch to _not_ implicitly enable
> e820_host when PCI devices are passed.
Builds, works with e820_host=0.

> 2) Mukesh's hypervisor e820 patch from here:
> http://lists.xen.org/archives/html/xen-devel/2013-05/msg01603.html
> Modified slightly to attempt to address Jan's comment on the same
> thread, and to adjust the diff line pointers to match against
> 4.3.0 release code.
Builds, works with e820_host=0.

> 3) A patch based on Konrad's earlier in this thread, with
> a few additions and changes to make it all compile.
Causes the domU to fail to start. No obvious errors in any logs, but the 
qemu-dm log simply stops before the usual point. There is blank white 
screen on VNC console. It looks like domU crashes before it even starts 
loading the OS.
I have attached two qemu-dm logs:
qemu-dm-edi.log - without patch 3
qemu-dm-edi.log.2 - with patch 3

I also attached the output of xl dmesg in each case.

With the 3rd patch applied, everything seems to stop just as the 
hypervisor is about to log the E820 table for HVM1 (obvious if you diff 
them).
This may be related to what I did to get your patch to build, Konrad.
The map never gets output, so either rc=-ENOSYS, or it crashes  during 
the hypercall.
With e820_host=0, the e820 map should be exactly the same as it would 
have been anyway, but something seems to go wrong during:
rc = hypercall_memory_op ( XENMEM_memory_map, &op);

Thoughts?

Gordan

Attachment: qemu-dm-edi.log
Description: Text document

Attachment: qemu-dm-edi.log.2
Description: Unix manual page

Attachment: dmesg.2.log
Description: Text document

Attachment: dmesg.log
Description: Text document

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