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Bug 1366919

Summary: extend virtio-net to expose host MTU to guest
Product: Red Hat Enterprise Linux 7 Reporter: Michael S. Tsirkin <mst>
Component: qemu-kvm-rhevAssignee: Maxime Coquelin <maxime.coquelin>
Status: CLOSED ERRATA QA Contact: xiywang
Severity: high Docs Contact:
Priority: high    
Version: 7.4CC: aconole, ailan, atelang, chayang, egarver, fbaudin, fleitner, hsowa, jbenc, juzhang, lrichard, mrezanin, psutter, rkhan, weliao, wtownsen, xiywang, zhengtli
Target Milestone: rcKeywords: FutureFeature
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: qemu-kvm-rhev-2.9.0-1.el7 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of:
: 1408701 1412234 (view as bug list) Environment:
Last Closed: 2017-08-01 23:32:13 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:    
Bug Blocks: 1395265, 1408701, 1411862, 1412234, 1429163, 1450162    

Description Michael S. Tsirkin 2016-08-14 23:54:32 UTC 
Description of problem:

It is useful to expose
host MTU to guest. In particular, guest can
then disable guest offloads and be sure that packets
will fit in MTU sized receive buffers,
and / or disable host offloads and still be sure
that packets can be transmitted.

Will need to clone to linux and dpdk down the road.
Comment 1 Maxime Coquelin 2016-12-05 13:52:19 UTC 
QEMU RFC v3 sent on the ML:
https://mail-archive.com/qemu-devel@nongnu.org/msg416009.html
Message-Id: <20161130101017.13382-1-maxime.coquelin>

In this version, the MTU value is specified by the user (management
tool) in QEMU command line via the host_mtu virtio-net parameter.
Comment 2 Maxime Coquelin 2017-01-19 09:10:34 UTC 
Upstream commits:
a93e599 virtio-net: Add MTU feature support
45a368a vhost-net: Notify the backend about the host MTU
c5f048d vhost-user: Add MTU protocol feature and op
Comment 4 xiywang 2017-06-07 01:13:31 UTC 
Verified.
Test result can be find in:
https://bugzilla.redhat.com/show_bug.cgi?id=1452756#c15
Related bug is:
https://bugzilla.redhat.com/show_bug.cgi?id=1412234
Comment 6 errata-xmlrpc 2017-08-01 23:32:13 UTC 
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/RHSA-2017:2392
Comment 7 errata-xmlrpc 2017-08-02 01:09:52 UTC 
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/RHSA-2017:2392
Comment 8 errata-xmlrpc 2017-08-02 02:01:51 UTC 
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/RHSA-2017:2392
Comment 9 errata-xmlrpc 2017-08-02 02:42:37 UTC 
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/RHSA-2017:2392
Comment 10 errata-xmlrpc 2017-08-02 03:07:20 UTC 
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/RHSA-2017:2392
Comment 11 errata-xmlrpc 2017-08-02 03:27:29 UTC 
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/RHSA-2017:2392