Bug 626277

Description of problem:
Create a HVM guest with vif model=rtl8130 which is misspelled in vif specification, xm create command does not return any error, but in virt-viewer could see error message "TCP/IP error:VNC connection to hypervisor host got refused or disconnected!" and when execute "ps aux |grep qemu-dm" could notice "[qemu-dm] <defunct>".

Version-Release number of selected component (if applicable):
xen-3.0.3-115.el5
kernel-xen-2.6.18-212.el5
host:rhel5.5 x86_64
guest:rhel5.5 i386

How reproducible:
Always

Steps to Reproduce:
1.Create a HVM guest with vif model misspelled.
2.virt-viewer
3.#ps aux |grep qemu-dm
4.#xm list
5.#cat /var/log/xen/qemu-dem.4592.log
6.#tail /var/log/xen/xend.log

Actual results:
At step1:
xm create command executed successfully without error.

At step3:
root      4592  0.0  0.0      0     0 ?        Z    11:00   0:00 [qemu-dm] <defunct>
root      4832  0.0  0.0  61196   748 pts/1    S+   11:01   0:00 grep qemu

At step4:
Name                                      ID Mem(MiB) VCPUs State   Time(s)
Domain-0                                   0     3296     2 r-----     34.5
rhel-5.5-32                                1      511     1 ------      0.0

At step5:
domid: 1
qemu: the number of cpus is 1
Watching /local/domain/1/logdirty/next-active
Watching /local/domain/0/device-model/1/command
xs_read(): vncpasswd get error. /vm/11bf03f8-1cbf-1d39-131c-970e25881cb7/vncpasswd.
qemu_map_cache_init nr_buckets = 10000
shared page at pfn 1ffff
buffered io page at pfn 1fffd
xs_read(/vm/11bf03f8-1cbf-1d39-131c-970e25881cb7/rtc/timeoffset): read error
qemu: Unsupported NIC: rtl8130

At step6: (xend hangs here)
[2010-08-23 11:00:23 xend 3541] DEBUG (DevController:538) hotplugStatusCallback /local/domain/0/backend/vbd/1/768/hotplug-status.
[2010-08-23 11:00:23 xend 3541] DEBUG (DevController:552) hotplugStatusCallback 1.
[2010-08-23 11:00:23 xend 3541] DEBUG (DevController:160) Waiting for devices irq.
[2010-08-23 11:00:23 xend 3541] DEBUG (DevController:160) Waiting for devices vkbd.
[2010-08-23 11:00:23 xend 3541] DEBUG (DevController:160) Waiting for devices vfb.
[2010-08-23 11:00:23 xend 3541] DEBUG (DevController:160) Waiting for devices pci.
[2010-08-23 11:00:23 xend 3541] DEBUG (DevController:160) Waiting for devices ioports.
[2010-08-23 11:00:23 xend 3541] DEBUG (DevController:160) Waiting for devices tap.
[2010-08-23 11:00:23 xend 3541] DEBUG (DevController:160) Waiting for devices vtpm.
[2010-08-23 11:00:23 xend 3541] INFO (XendDomain:386) Domain rhel-5.5-32 (1) unpaused.

Expected results:
Xend should check the vif model available or not before really create the HVM guest, if not available report an detailed error message to user or use the default model rtl8139 as a replacement, just like it change xvda to hda when the first disk specified with blktap driver which is actually not supported.