[Xen-devel] Problem with migrating/saving 2.6.30 vanilla kernel with multiple VCPUs

[Denis Chapligin <chollya@xxxxxxxxxxx>]

Hi

I have xen 3.4.1 installed, with dom0 running linux-2.6.18-xen.hg (four
weeks old) I've made a domU with a vanilla 2.6.30.4 kernel and tried to
save it to a file. 
xm save command stuck and resulting file was only 1503 bytes.

Here are some details - xm list after xm save command:
dom0:~# xm list
Name                                        ID   Mem VCPUs      State
Time(s) Domain-0                                     0   254     1
r-----     90.7 migrating-test                               9
256     4 -b----     12.3

Snapshot file:
dom0:/tmp# ls -l 
total 0
-rwxr-xr-x 1 root root 1503 2009-08-10 10:51 test.mem

Contents of test.mem file:
dom0:/tmp# cat test.mem 
LinuxGuestRecordïdomain (domid 9) (on_crash restart) (uuid
e3ac4f7e-d1e4-e9ce-8d9f-dfb229ced941) (bootloader_args ) (vcpus 4)
(name test) (on_poweroff destroy) (on_reboot restart) (cpus (() () ()
())) (bootloader ) (maxmem 256) (memory 256) (shadow_memory 0)
(vcpu_avail 15) (features ) (on_xend_start ignore) (on_xend_stop
ignore) (start_time 1249890685.85) (cpu_time 0.0) (online_vcpus 1)
(image (linux (kernel /GFS/kernels/vmlinuz-2.6.30.4)
(ramdisk /GFS/kernels/initrd.img-2.6.30.4) (args 'root=/dev/xvda
clocksource=jiffies') (videoram 4) (notes (HV_START_LOW 4118806528)
(FEATURES '!writable_page_tables|pae_pgdir_above_4gb') (VIRT_BASE
3221225472) (GUEST_VERSION 2.6) (PADDR_OFFSET 0) (GUEST_OS linux)
(HYPERCALL_PAGE 3222282240) (LOADER generic) (SUSPEND_CANCEL 1)
(PAE_MODE yes) (ENTRY 3225649152) (XEN_VERSION xen-3.0)))) (status 2)
(state --p---) (store_mfn 1165228) (console_mfn 1165227) (device (vif
(bridge br6) (mac 00:16:3e:2e:4c:8b)
(script /etc/xen/scripts/vif-bridge) (uuid
668ceb77-5657-79d0-a6d8-20442e718d79) (backend 0))) (device (vbd
(protocol x86_32-abi) (uuid da6930eb-f7eb-893e-6d87-a27db331b957)
(bootable 1) (dev xvda:disk) (uname phy:/dev/etherd/e1.2) (mode w)
(backend 0) (bootable 1) (VDI ))) (device (console (protocol vt100)
(location 2) (uuid becf1aa4-e58c-7404-f2ff-8e33ec7f788e))) (cpuid
((2147483648 ((eax 00000000000000000000000000000011) (edx
00000000000000000000000000000000) (ebx
00000000000000000000000000000000) (ecx
00000000000000000000000000000000))))))

There is nothing on xen's dmesg and dom0 dmesg. Here are part of
xend.log:
[2009-08-10 10:51:45 2186] DEBUG (XendCheckpoint:110)
[xc_save]: /usr/lib/xen-3.4/bin/xc_save 46 9 0 0 0 
[2009-08-10 10:51:452186] DEBUG (XendCheckpoint:388) suspend 
[2009-08-10 10:51:45 2186]DEBUG (XendCheckpoint:113) In
saveInputHandler suspend 
[2009-08-1010:51:45 2186] DEBUG (XendCheckpoint:115) Suspending 9 ... 
[2009-08-1010:51:45 2186] DEBUG (XendDomainInfo:511)
XendDomainInfo.shutdown(suspend) 
[2009-08-10 10:51:45 2186] DEBUG
(XendDomainInfo:1709) XendDomainInfo.handleShutdownWatch 
[2009-08-1010:51:45 2186] DEBUG (XendDomainInfo:1709)
XendDomainInfo.handleShutdownWatch 
[2009-08-10 10:51:45 2186] INFO(XendCheckpoint:417) xc_save: failed to
get the suspend evtchn port 

Xen's info:
dom0:~# xm info
host                   : dom0
release                : 2.6.18.8
version                : #1 SMP Tue Jul 7 18:42:07 EEST 2009
machine                : i686
nr_cpus                : 4
nr_nodes               : 1
cores_per_socket       : 1
threads_per_core       : 2
cpu_mhz                : 2992
hw_caps                :
bfebfbff:20000800:00000000:00000180:0000641d:00000000:0 0000000:00000000
virt_caps              : 
total_memory           : 4095
free_memory            : 3529
node_to_cpu            : node0:0-3
node_to_memory         : node0:3529
xen_major              : 3
xen_minor              : 4
xen_extra              : 
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p 
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xff800000
xen_changeset          : unavailable
cc_compiler            : gcc version 4.3.2 (Debian 4.3.2-1.1) 
cc_compile_by          : chollya
cc_compile_domain      : satgate.net
cc_compile_date        : Fri Aug  7 11:54:19 EEST 2009
xend_config_format     : 4

and the domain configuration file:
dom0:~# cat /GFS/xen/test.cfg 
kernel="/GFS/kernels/vmlinuz-2.6.30.4"
ramdisk="/GFS/kernels/initrd.img-2.6.30.4"
root="/dev/xvda"
extra="clocksource=jiffies"
memory = 256
cpuid=['0x80000000:eax=0x3,ebx=0x0,ecx=0x0,edx=0x0']
name = "test"
vcpus = 4
vif = ['bridge=br6']
disk = ['phy:/dev/etherd/e1.2,xvda,w']


Save/migrate works fine when i use linux-2.6.18-xen.hg as a domU
kernel, so i suppose it could be a bug somewhere, not a configuration
issue.

-- 
                                                Denis Chapligin

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