Created attachment 1152202 [details]
Booting pre-installed pv image failed.

Description of problem:
There is no response when installing a pv guest on Fedora24 xen-4.6.1 host, and the boot process hangs with message "Starting monitoring for VG vg_dhcp66145125:" when booting a pre-installed pv image.

Version-Release number of selected component (if applicable):
Host Fedora24 with:
kernel-4.5.2-301.fc24.x86_64
xen-4.6.1-6.fc24.x86_64

Guest RHEL6.8 with:
kernel-2.6.32-642.el6.x86_64

How reproducible:
Always

Precondition:
The xenstored.service failed when booting xen hypervisor, should insert xen modules manually and start the service again as below:
xen_wdt               
xen_pciback            
xen_netfront    
xen_netback           
xen_gntdev  
xen_gntalloc         
xen_evtchn            
xen_blkfront    
xen_blkback           
xen_acpi_processor   

Steps to Reproduce:
1. Create a disk for the guest with command:
   # dd if=/dev/zero of=/mnt/xen-pv-64.img bs=1M count=10000
2. Create a RHEL6.8 pv guest on Fedora24 Xen, with xl command and the configure file including below lines:
   name = "xen-pv-64"
   maxmem = 1024
   memory = 1024
   vcpus = 2
   kernel = "/root/vmlinuz"
   ramdisk = "/root/initrd.img"
   extra = "method=http://download.eng.pek2.redhat.com/pub/rhel/rel-eng/RHEL-6.8-20160414.0/compose/Server/x86_64/os/"
   on_poweroff = "restart"
   on_reboot = "restart"
   on_crash = "destroy"
   vfb = [ 'type=vnc,vncunused=1,keymap=en-us,vnclisten=0.0.0.0' ]
   disk = [ "file:/mnt/xen-pv-64.img,xvda,w" ]
   vif = [ "mac=00:16:36:63:75:48,bridge=xenbr0,script=vif-bridge" ]
   serial = "pty"

3. Check the guest status and connect guest with console or vnc to continue installation.

Actual results:
The PV guest status is "r" and no response when connecting guest with console or vnc. Cannot connect the guest with vncviewer, but the screen is black and no response.  
[root@dhcp-9-56 ~]# xl list
Name                                        ID   Mem VCPUs        State        Time(s)
Domain-0                                     0  5891     8     r-----      77.3
xen-pv-64                                    6  1024     1     r-----    1211.7

Expected results:  
The pv guest status should be "b" and when connecting guest with vncviewer, the installation wizard will display.

Additional info:
1. If create a pre-installed pv image with xl command and below configuration file:
[root@dhcp-9-56 ~]# cat xen-pv-guest.cfg
name = "xen-pv-6"
memory = 1024
vcpus = 2
bootloader = "/usr/bin/pygrub"
vnc = 1
vncconsole = 1
on_poweroff = "destroy"
on_reboot = "restart"
on_crash = "restart"
vfb = [ 'type=vnc,vncunused=1,keymap=en-us,vnclisten=0.0.0.0' ]
disk = [ "file:/home/RHEL-Server-6.8-32-20160414.0-pv.raw,xvda,w" ]
vif = [ "mac=00:16:36:43:73:e7,bridge=xenbr0,script=vif-bridge" ]
serial = "pty"

The pv guest status is also "r" and no response when connecting guest with console. If connect guest with vncviewer, it will display the boot progress hangs in step:
"Starting monitoring for VG vg_dhcp66145125:" as in attachment.

2. Create a pvhvm guest with hvmloader but xvda disk driver, the guest will boot as normal and this step start OK as below:
"Starting monitoring for VG vg_dhcp66145125: [OK]"

3. Booting the same pre-installed pv image in xen-4.5.2 on Fedora23 Host is also OK.