Bug 1456403
| Summary: | Net-KVM: Implement MTU report feature of the virtio-net device | ||
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| Product: | Red Hat Enterprise Linux 7 | Reporter: | Sameeh Jubran <sjubran> |
| Component: | virtio-win | Assignee: | Sameeh Jubran <sjubran> |
| virtio-win sub component: | virtio-win-prewhql | QA Contact: | Virtualization Bugs <virt-bugs> |
| Status: | CLOSED ERRATA | Docs Contact: | |
| Severity: | unspecified | ||
| Priority: | unspecified | CC: | ailan, jherrman, juzhang, lijin, lmiksik, lprosek, michen, mtessun, vrozenfe |
| Version: | 7.5 | Keywords: | RFE |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Enhancement | |
| Doc Text: |
The NetKVM driver is now able to obtain the maximum transmission unit (MTU) of a host and apply it to Windows guests running on this host. As a result, the user can optimize the guest's network interface controller (NIC) when the host MTU value is different than the default 1500 bytes.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2017-08-01 12:58:08 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 1452756 | ||
| Bug Blocks: | |||
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Description
Sameeh Jubran
2017-05-29 10:25:10 UTC
In order to test the feature, the parameter "host_mtu" should be set in the virtio-net's parameters in Qemu command line. For example: -netdev tap,id=hostnet1,script=world_bridge_standalone.sh,downscript=no,ifname=cc1_72 \ -device virtio-net,netdev=hostnet1,mac=56:cc:c1:04:2c:21,id=cc1_72,host_mtu=4000 \ In order to verify that the feature is working correctly from the guest you should run the command "netsh interface ipv4 show subinterfaces" in the command prompt, the Net-KVM interface's MTU should be the same as whatever host_mtu is to. should be fixed in build 139 http://download.eng.bos.redhat.com/brewroot/work/tasks/1396/13321396/virtio-win-prewhql-0.1.zip steps: 1.boot guest with netkvm device and add "host_mtu=4000" -netdev tap,id=hostnet1,script=/etc/qemu-ifup,vhost=on,queues=2 -device virtio-net-pci,host_mtu=4000,mq=on,vectors=6,netdev=hostnet1,mac=4e:63:28:bc:b1:01,id=net1 2.check guest mtu value in cmd: # netsh interface ipv4 show subinterfaces 3.from external host,ping guest 4.from guest,ping external host Result: After step2,mtu is 4000 as expected: MTU MediaSenseState Bytes In Bytes Out Interface ------ --------------- --------- --------- ------------- 4294967295 1 0 0 Loopback Pseudo-Interface 1 4000 1 5509 6678 Ethernet ping can pass after step3 and step4,network works normally. So this bug is fixed,thanks. verified packages info: virtio-win-prewhql-139 kernel-3.10.0-675.el7.x86_64 qemu-kvm-rhev-2.9.0-8.el7.x86_64 seabios-1.10.2-2.el7.x86_64 Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2017:2341 |