Re: How to dump vcpu regs when a domain is killed during xl create

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 19/08/14 11:02, manish jaggi wrote:
> On 19 August 2014 14:31, Andrew Cooper <andrew.cooper3@citrix.com> wrote:
>> On 19/08/14 06:11, manish jaggi wrote:
>>> Adding the question on xen-devel
>>>
>>> On 18 August 2014 14:08, manish jaggi <manishjaggi.oss@gmail.com> wrote:
>>>> I tried to start a domain using xl create, which showed some xen logs
>>>> and then hanged for a minute or so and then displayed a messgae
>>>> killed. Below is the log
>>>>
>>>> linux:~ # xl create domU.cfg
>>>> Parsing config from domU.cfg
>>>> (XEN)  ....
>>>> Killed
>>>>
>>>> Is there a way to know why it was killed and dump core regs (vcpu
>>>> regs) at the point it was killed.
>> There is no guarantee the domain has successfully started.
>>
>> Put "loglvl=all guest_loglvl=all" on the Xen command line, reboot, and
>> attach the results of
>>
>> xl -vvvv create domU.cfg
>>
>> and xl dmesg after the domain has failed in this way.
>>
>> ~Andrew
> Below is the log
> linux:~ # xl -vvv create domU.cfg -d -p
> Parsing config from domU.cfg
> {
>     "domid": null,
>     "config": {
>         "c_info": {
>             "type": "pv",
>             "name": "guest",
>             "uuid": "e5cb14f1-085d-4511-bca5-d6e3a0c35672",
>             "run_hotplug_scripts": "True"
>         },
>         "b_info": {
>             "max_vcpus": 1,
>             "avail_vcpus": [
>                 0
>             ],
>             "max_memkb": 262144,
>             "target_memkb": 262144,
>             "shadow_memkb": 3072,
>             "sched_params": {
>
>             },
>             "claim_mode": "True",
>             "type.pv": {
>                 "kernel": "/root/Image",
>                 "cmdline": "console=hvc0 root=/dev/xvda ro"
>             }
>         },
>         "disks": [
>             {
>                 "pdev_path": "/dev/loop0",
>                 "vdev": "xvda",
>                 "format": "raw",
>                 "readwrite": 1
>             }
>         ],
>         "on_reboot": "restart"
>     }
> }
>
> libxl: verbose:
> libxl_create.c:134:libxl__domain_build_info_setdefault: qemu-xen is
> unavailable, use qemu-xen-traditional instead: No such file or
> directory
> libxl: debug: libxl_create.c:1401:do_domain_create: ao 0xd297c20:
> create: how=(nil) callback=(nil) poller=0xd293d90
> libxl: debug: libxl_device.c:251:libxl__device_disk_set_backend: Disk
> vdev=xvda spec.backend=unknown
> libxl: debug: libxl_device.c:280:libxl__device_disk_set_backend: Disk
> vdev=xvda, using backend phy
> libxl: debug: libxl_create.c:851:initiate_domain_create: running bootloader
> libxl: debug: libxl_bootloader.c:329:libxl__bootloader_run: no
> bootloader configured, using user supplied kernel
> libxl: debug: libxl_event.c:618:libxl__ev_xswatch_deregister: watch
> w=0xd294648: deregister unregistered
> domainbuilder: detail: xc_dom_allocate: cmdline="console=hvc0
> root=/dev/xvda ro", features="(null)"
> libxl: debug: libxl_dom.c:410:libxl__build_pv: pv kernel mapped 0 path
> /root/Image
> domainbuilder: detail: xc_dom_kernel_file: filename="/root/Image"
> domainbuilder: detail: xc_dom_malloc_filemap    : 8354 kB
> domainbuilder: detail: xc_dom_boot_xen_init: ver 4.5, caps
> xen-3.0-aarch64 xen-3.0-armv7l
> domainbuilder: detail: xc_dom_rambase_init: RAM starts at 40000
> domainbuilder: detail: xc_dom_parse_image: called
> domainbuilder: detail: xc_dom_find_loader: trying multiboot-binary loader ...
> domainbuilder: detail: loader probe failed
> domainbuilder: detail: xc_dom_find_loader: trying Linux zImage (ARM64)
> loader ...
> domainbuilder: detail: loader probe OK
> domainbuilder: detail: xc_dom_parse_zimage64_kernel: called
> domainbuilder: detail: xc_dom_parse_zimage64_kernel: xen-3.0-aarch64:
> 0x40080000 -> 0x408a8b50
> libxl: debug: libxl_arm.c:474:libxl__arch_domain_init_hw_description:
> constructing DTB for Xen version 4.5 guest
> libxl: debug: libxl_arm.c:291:make_memory_nodes: Creating placeholder
> node /memory@40000000
> libxl: debug: libxl_arm.c:291:make_memory_nodes: Creating placeholder
> node /memory@200000000
> libxl: debug: libxl_arm.c:539:libxl__arch_domain_init_hw_description:
> fdt total size 1218
> domainbuilder: detail: xc_dom_devicetree_mem: called
> domainbuilder: detail: xc_dom_mem_init: mem 256 MB, pages 0x10000 pages, 4k each
> domainbuilder: detail: xc_dom_mem_init: 0x10000 pages
> domainbuilder: detail: xc_dom_boot_mem_init: called
> domainbuilder: detail: set_mode: guest xen-3.0-aarch64, address size 6
> domainbuilder: detail: xc_dom_malloc            : 512 kB
> domainbuilder: detail: populate_guest_memory: populating RAM @
> 0000000040000000-0000000050000000 (256MB)
> domainbuilder: detail: populate_one_size: populated 0x80/0x80 entries
> with shift 9
> domainbuilder: detail: arch_setup_meminit: placing boot modules at 0x48000000
> domainbuilder: detail: arch_setup_meminit: devicetree: 0x48000000 -> 0x48001000
> libxl: debug: libxl_arm.c:570:finalise_one_memory_node: Populating
> placeholder node /memory@40000000
> libxl: debug: libxl_arm.c:564:finalise_one_memory_node: Nopping out
> placeholder node /memory@200000000
> domainbuilder: detail: xc_dom_build_image: called
> domainbuilder: detail: xc_dom_alloc_segment:   kernel       :
> 0x40080000 -> 0x408a9000  (pfn 0x40080 + 0x829 pages)
> Killed

That is only half of the items I asked for, but this indicates that
something in dom0 killed the domain builder while it was constructing
the domain.

Try consulting dom0's dmesg.

~Andrew