Re: automatically detaching PCI host devices from guest for SRIOV usage.

[Alex Jia <ajia@xxxxxxxxxx>]

On 08/21/2012 11:22 AM, Rajesh Kumar Mallah wrote:

Dear Alex / List  ,

Thanks for the response.

The problem is regarding detaching from the guest not host.

I see, if you attach a PCI device into guest with 'managed' mode(managed='yes') then the device is automatically detached from guest and returned to host after guest exiting, for example.

# lspci | grep Eth
00:19.0 Ethernet controller: Intel Corporation 82566DM-2 Gigabit Network Connection (rev 02)

# readlink /sys/bus/pci/devices/0000\:00\:19.0/driver/ -f
/sys/bus/pci/drivers/e1000e

# virsh start foo
Domain foo started

# ping -c 3 xx.xx.xx.xx
PING xx.xx.xx.xx (xx.xx.xx.xx) 56(84) bytes of data.
64 bytes from nx-in-f160.1e100.net (xx.xx.xx.xx): icmp_seq=1 ttl=49 time=87.8 ms
64 bytes from nx-in-f160.1e100.net (xx.xx.xx.xx): icmp_seq=2 ttl=49 time=85.2 ms
64 bytes from nx-in-f160.1e100.net (xx.xx.xx.xx): icmp_seq=3 ttl=49 time=91.8 ms
--- xx.xx.xx.xx ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2093ms
rtt min/avg/max/mdev = 85.240/88.327/91.881/2.731 ms

# cat hostdev.xml
<hostdev mode='subsystem' type='pci' managed='yes'>
   <source>
      <address domain='0x0000' bus='0x00' slot='0x19' function='0x0'/>
   </source>
</hostdev>

# virsh attach-device foo hostdev.xml
Device attached successfully

# readlink /sys/bus/pci/devices/0000\:00\:19.0/driver/ -f
/sys/bus/pci/drivers/pci-stub

# ping -c 3 xx.xx.xx.xx
connect: Network is unreachable

# virsh destroy foo
Domain foo destroyed

# readlink /sys/bus/pci/devices/0000\:00\:19.0/driver/ -f
/sys/bus/pci/drivers/e1000e

# ping -c 3 xx.xx.xx.xx
PING xx.xx.xx.xx (xx.xx.xx.xx) 56(84) bytes of data.
64 bytes from xx.xx.xx.xx: icmp_seq=1 ttl=49 time=79.7 ms
64 bytes from xx.xx.xx.xx: icmp_seq=2 ttl=49 time=83.2 ms
64 bytes from xx.xx.xx.xx: icmp_seq=3 ttl=49 time=84.5 ms

--- xx.xx.xx.xx ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2087ms
rtt min/avg/max/mdev = 79.714/82.480/84.513/2.040 ms

Notes, need to wait for local network recovery again then check network connectivity.

If your network still is disconnect, it may be a bug IMHO, please show your libvirt
and qemu-kvm version, or my example is not what you want, please let me know.

Thanks,
Alex

In our case since ixgbevf driver is NOT present in the host hence the virtual
interfaces never really attach themselves to the host.

Regards,
Rajesh Kumar Mallah
Tel. 91-11-46710500 (Ext:303)
Cell +919811255597
Website: http://www.tradeindia.com/
\|/ \|/ \|/   stop printing   \|/ \|/ \|/
 |   |   |    start planting   |   |   |


----- "Alex Jia" <ajia@xxxxxxxxxx> wrote:
| From: "Alex Jia" <ajia@xxxxxxxxxx>
| To: "Rajesh Kumar Mallah" <mallah@xxxxxxxxxxxxxx>
| Cc: libvirt-users@xxxxxxxxxx
| Sent: Tuesday, August 21, 2012 8:31:21 AM
| Subject: Re: automatically detaching PCI host devices from guest for SRIOV usage.
|
| On 08/20/2012 08:34 PM, Rajesh Kumar Mallah wrote:

Dear List ,

We are using intel 82599EB based SRIOV capable 10GbE cards
on the host machine.The VFs are being assigned to the guest 
in pass through mode and are providing the network connectivity 
as expected.

However when we shutdown the guest the connectivity does not
comes back via the VFs on the guest in next boot unless
the VFs are detached from the *guest* *before* initiating a
shutdown of the guests.

Dear Rajesh,
|
| Please see the following comments.
|
|

( 
the detach is explicitly done via virsh command 
/usr/local/libvirt/bin/virsh  detach-device guest01   ~/nic.xml
nic.xml contained
<hostdev mode='subsystem' type='pci' managed='yes'>
   <source>
      <address domain='0x0000' bus='0x04' slot='0x10' function='0x0'/>
   </source>
   <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</hostdev>
)

The question is anyone else facing similar problem and
if so what solution was used?

Secondly , is there anyway to automate the detaching of the
VFs from the guest when the guest is put in the shutdown 
sequence ? (or for that matter destroyed).

| When managed is "yes" for a PCI device, it is automatically detached from the host before being passed on to the guest, and automatically reattached to the host after the guest exits such as shutdown a guest.
|
| Regards,
| Alex
|
|

Regards,
Rajesh Kumar Mallah
Tel. 91-11-46710500 (Ext:303)
Cell +919811255597
Website: http://www.tradeindia.com/
\|/ \|/ \|/   stop printing   \|/ \|/ \|/
 |   |   |    start planting   |   |   |

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