Re: [Xen-devel] kexec and kdump on Xen??

["Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx>]

Daniel Kiper wrote on 2014-04-14:
> Hey,
> 
> On Mon, Apr 14, 2014 at 08:15:35AM +0000, Zhang, Yang Z wrote:
>> Daniel Kiper wrote on 2014-04-14:
>>> Hi,
>>> 
>>> On Mon, Apr 14, 2014 at 03:38:26AM +0000, Zhang, Yang Z wrote:
>>>> Hi Daniel
>>>> 
>>>> Are kexec/kdump supported by latest Xen + upstream Linux?
>>>> I remember it only works with xen+2.6.18 linux. I know you are
>>>> working on enable it. So I wonder to know what the current status is.
> Thanks.
>>> 
>>> Xen 4.4 has new kexec implementation written by David Vrabel.
>>> It does not require any specific Linux Kernel version because this
>>> implementation is self contained. However, please do not forget to
>>> use
>> 
>> Cool..
>> 
>>> latest stable version of kexec-tools too.
>> 
>> Is there any BKM to use it? I saw an old wiki page but not sure
>> whether it is still suitable.
> 
> I assume that you are asking about kexec/kdump support in dom0.
> 
> Just build kexec-tools with Xen support enabled (you must provide
> relevant Xen header files and libraries).
> Then add crashkernel argument to Xen (e.g. crashkernel=512m@64m) and
> reboot machine. Use kexec-tools like on bare metal machines.

I am trying to kexec from Xen to Linux. But it fails to work.
./kexec -l /boot/vmlinuz-2.6.32-358.el6.x86_64 

kexec_load failed: Invalid argument
entry       = 0x7fff6760 flags = 0x3e0000
nr_segments = 3
segment[0].buf   = 0x138f660
segment[0].bufsz = 0x3641
segment[0].mem   = 0x3000
segment[0].memsz = 0x4000
segment[1].buf   = 0x7fc68badf610
segment[1].bufsz = 0x3d8110
segment[1].mem   = 0x1000000
segment[1].memsz = 0x3d9000
segment[2].buf   = 0x1387540
segment[2].bufsz = 0x80e0
segment[2].mem   = 0x7fff6000
segment[2].memsz = 0xa000


Here is my environment:
Xen version: latest Xen
Xen boot command:
        kernel (hd0,0)/boot/xen.gz dom0_mem=4096M loglvl=all guest_loglvl=all 
conring_size=4M crashkernel=128M@64M
    module (hd0,0)/boot/vmlinuz-xen o 
root=UUID=03a5e7c4-b8d0-45b4-a090-c34b06821cea pci=noaer max_loop=64 3 debug
    module (hd0,0)/boot/initrd-xen.img
kexec version with Xen enabled:  kexec-tools 2.0.6 released 18 April 2014

Also, it shows error when trying to kexec (Xen -> Xen)
./kexec -l /boot/xen.gz
Segmentation fault (core dumped)

BTW: kexec from Linux to Linux works well.

Best regards,
Yang



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