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Cause: vhost keeps being enabled when qemu NIC link is set to 'off'.
Consequence: 'set_link <tap> off' doesn't work when using vhost-net.
Fix: disable vhost when 'set_link <tap> off' monitor command is used.
Result: 'set_link <tap> off' monitor command now works when using vhost.
DescriptionMichael S. Tsirkin
2011-02-08 15:54:09 UTC
Test Procedure:
-----------------------
1) Boot up guest with one nic
2) Ping guest from host
3) Disable guest link from qemu monitor using set_link <adapter>
off and ping guest from host
4) Re-enable guest link and ping guest from host
Expected results:
-------------------------
When guest network link is disabled using "set_link" command from
qemu monitor, guest network should go down and then host shouldnt be
pingable from guest.
Actual results:
--------------------
i tried to disable netowrk link using "set_link",
When vhost is enabled, network never goes down for guest.
When vhost disabled, set_link works as expected.
Guest Kernel:
------------------
2.6.32-71.el6.x86_64
Host Kernel:
-----------------------
2.6.37.rc8 on HS22
command used:
-------------------------
/usr/local/bin/qemu-system-x86_64 -name vm1 -monitor
unix:/tmp/monitor-humanmonitor1-20110128-125452-iQor,server,nowait
-serial unix:/tmp/serial-20110128-125452-iQor,server,nowait -drive
file=/tmp/kvm_autotest_root/images/rhel6-64.raw,index=0,if=virtio,cache=none,boot=on
-device virtio-net-pci,netdev=idDUN4bZ,mac=9a:85:7a:7f:c1:94 -netdev
tap,id=idDUN4bZ,vhost=on,ifname=t0-125452-iQor,script=/home/new/autotest/client/tests/kvm/scripts/qemu-ifup,downscript=no
-m 1024 -smp 2 -vnc :0 -monitor stdio
Qemu_monitor commands used:
(qemu) set_link idDUN4bZ off
(qemu) set_link idDUN4bZ on
(qemu) set_link idDUN4bZ off
--Pradeep
Notes:
- set_link on the virtio device works fine.
- link state was tested by ping
Verify this bug with qemu-kvm-0.12.1.2-2.146.el6 as following steps:
Test Procedure:
----------------
1.boot guest with vhost=off, ping guest from host.
2.in qemu monitor:
(qemu)set_link hostnet0 off
3.in qemu monitor:
(qemu)set_link hostnet0 on
4.boot guest with vhost=on, then do step 2-3
Actual results:
----------------
Both vhost=on/off works correctly.
Conclusion:
---------------
According to above results, this bug has been resolved.
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
New Contents:
Cause: vhost keeps being enabled when qemu NIC link is set to 'off'.
Consequence: 'set_link <tap> off' doesn't work when using vhost-net.
Fix: disable vhost when 'set_link <tap> off' monitor command is used.
Result: 'set_link <tap> off' monitor command now works when using vhost.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.
http://rhn.redhat.com/errata/RHSA-2011-0534.html
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.
http://rhn.redhat.com/errata/RHSA-2011-0534.html
Test Procedure: ----------------------- 1) Boot up guest with one nic 2) Ping guest from host 3) Disable guest link from qemu monitor using set_link <adapter> off and ping guest from host 4) Re-enable guest link and ping guest from host Expected results: ------------------------- When guest network link is disabled using "set_link" command from qemu monitor, guest network should go down and then host shouldnt be pingable from guest. Actual results: -------------------- i tried to disable netowrk link using "set_link", When vhost is enabled, network never goes down for guest. When vhost disabled, set_link works as expected. Guest Kernel: ------------------ 2.6.32-71.el6.x86_64 Host Kernel: ----------------------- 2.6.37.rc8 on HS22 command used: ------------------------- /usr/local/bin/qemu-system-x86_64 -name vm1 -monitor unix:/tmp/monitor-humanmonitor1-20110128-125452-iQor,server,nowait -serial unix:/tmp/serial-20110128-125452-iQor,server,nowait -drive file=/tmp/kvm_autotest_root/images/rhel6-64.raw,index=0,if=virtio,cache=none,boot=on -device virtio-net-pci,netdev=idDUN4bZ,mac=9a:85:7a:7f:c1:94 -netdev tap,id=idDUN4bZ,vhost=on,ifname=t0-125452-iQor,script=/home/new/autotest/client/tests/kvm/scripts/qemu-ifup,downscript=no -m 1024 -smp 2 -vnc :0 -monitor stdio Qemu_monitor commands used: (qemu) set_link idDUN4bZ off (qemu) set_link idDUN4bZ on (qemu) set_link idDUN4bZ off --Pradeep Notes: - set_link on the virtio device works fine. - link state was tested by ping