I'm not sure if this is a bug or my fault, but when I create a domain
with a vTPM attached, detaching it sometimes causes the following error
to be thrown (I post the command sequence):
[root@localhost ~]# xl create /etc/xen/vtpmmgr-stubdom
Parsing config from /etc/xen/vtpmmgr-stubdom
[root@localhost ~]# xl create /etc/xen/vtpm1
Parsing config from /etc/xen/vtpm1
[root@localhost ~]# xl create /etc/xen/dom1_ima
Parsing config from /etc/xen/dom1_ima
[root@localhost ~]# xl vtpm-detach dom1 vtpm1
[root@localhost ~]# xl destroy dom1
[root@localhost ~]# xl vtpm-detach vtpm1 vtpmmgr
libxl: error: libxl_device.c:952:device_backend_callback: unable to
remove device with path /local/domain/18/backend/vtpm/19/0
libxl: error: libxl.c:1995:device_addrm_aocomplete: unable to remove
vtpm with id 0
libxl_device_vtpm_remove failed.
Sometimes the error is raised while detaching vtpmmgr from vtpm (as
reported), other times while detaching vtpm from domain. I think
this could be a synchronization problem.
I report some info:
[root@localhost ~]# xl info
host : localhost.localdomain
release : 3.18.25-19.without_tpm.el7.centos.x86_64
version : #1 SMP Sun Apr 10 18:10:14 CEST 2016
machine : x86_64
nr_cpus : 2
max_cpu_id : 3
nr_nodes : 1
cores_per_socket : 2
threads_per_core : 1
cpu_mhz : 2394
hw_caps : bfebfbff:20100800:00000000:00000900:0408e3fd:00000000:00000001:00000000
virt_caps : hvm hvm_directio
total_memory : 3996
free_memory : 2888
sharing_freed_memory : 0
sharing_used_memory : 0
outstanding_claims : 0
free_cpus : 0
xen_major : 4
xen_minor : 6
xen_extra : .1-5.el7
xen_version : 4.6.1-5.el7
xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xffff800000000000
xen_changeset : Tue Mar 29 11:02:43 2016 +0100 git:8210a62-dirty
xen_commandline : placeholder dom0_mem=1024M,max:1024M cpuinfo com1=115200,8n1 console=com1,tty loglvl=all guest_loglvl=all
cc_compiler : gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-4)
cc_compile_by : mockbuild
cc_compile_domain : centos.org
cc_compile_date : Tue Mar 29 12:15:50 UTC 2016
xend_config_format : 4
[root@localhost ~]# cat /etc/xen/vtpmmgr-stubdom
name = "vtpmmgr"
kernel="/usr/lib/xen/boot/vtpmmgr-stubdom.gz"
memory=16
disk=["file:/srv/xen/vtpmmgr-stubdom.img,hda,w"]
iomem=["fed40,5"]
[root@localhost ~]# cat /etc/xen/vtpm1
name="vtpm1"
kernel="/usr/lib/xen/boot/vtpm-stubdom.gz"
memory=8
disk=["file:/srv/xen/vtpm1.img,hda,w"]
vtpm=["backend=vtpmmgr,uuid=8aca22b3-768a-41e7-b2cb-123d23901996"]
[root@localhost ~]# cat /etc/xen/dom1_ima
kernel = "/srv/xen/vmlinuz-xen"
ramdisk = "/srv/xen/initrd-xen"
name = "dom1"
memory = "512"
disk = [ 'tap:aio:/srv/xen/dom1.img,xvda1,w' ]
vcpus=1
root = '/dev/xvda1 ro'
extra = 'ima_tcb'
vtpm=['backend=vtpm1']
