Bug 616501

Summary:	publish used ABI incompatible with future guests
Product:	Red Hat Enterprise Linux 6	Reporter:	Michael S. Tsirkin <mst>
Component:	qemu-kvm	Assignee:	Michael S. Tsirkin <mst>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	low
Version:	6.0	CC:	khong, llim, mkenneth, syeghiay, tburke, virt-maint
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	qemu-kvm-0.12.1.2-2.98.el6	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:
Clones:	616503 (view as bug list)		Environment:
Last Closed:	2010-11-10 21:26:42 UTC	Type:	---
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:	616503

Description Michael S. Tsirkin 2010-07-20 15:48:41 UTC

Description of problem:
publish used feature was revertred upstream,
and discussion is ongoing to make it trigger
layout change that won't be compatible with RHEL.

This will be a big problem with support going forward,
so the right thing for now is to revert this in RHEL6,
as performance gain from it is minor.

Version-Release number of selected component (if applicable):
2:0.12.1.2-2.90.el6

How reproducible:
always

Steps to Reproduce:
1. boot rhel6 guest with virtio-net
2. look at features
  
Actual results:
bit 29 should be off

Expected results:
bit 29 is on

Additional info:

Comment 5 Keqin Hong 2010-07-30 07:36:38 UTC

Reproduced in qemu-kvm-0.12.1.2-2.97 and verified in qemu-kvm-0.12.1.2-2.99.

Steps:
1. boot a rhel6 guest with "-netdev tap,id=hostnet0,vhost=on"
2. under qemu monitor, execute "info qtree"

Result: publish_used feature is removed

(qemu) info qtree
...
dev: virtio-net-pci, id "net0"
        dev-prop: vectors = 3
        dev-prop: indirect_desc = off
        dev-prop: publish_used = off
        dev-prop: csum = on
        dev-prop: guest_csum = on
        dev-prop: gso = on
        dev-prop: guest_tso4 = on
        dev-prop: guest_tso6 = off
        dev-prop: guest_ecn = off
        dev-prop: guest_ufo = off
        dev-prop: host_tso4 = off
        dev-prop: host_tso6 = off
        dev-prop: host_ecn = off
        dev-prop: host_ufo = off
        dev-prop: mrg_rxbuf = off
        dev-prop: status = off
        dev-prop: ctrl_vq = off
        dev-prop: ctrl_rx = off
        dev-prop: ctrl_vlan = off
        dev-prop: ctrl_rx_extra = off
        dev-prop: mac = 54:52:00:1d:c0:af
        dev-prop: vlan = <null>
        dev-prop: netdev = hostnet0
        bus-prop: addr = 04.0
        bus-prop: romfile = "pxe-virtio.bin"
        bus-prop: rombar = 1
        class Ethernet controller, addr 00:04.0, pci id 1af4:1000 (sub 1af4:0001)
        bar 0: i/o at 0xffffffffffffffff [0x1e]
        bar 1: mem at 0xffffffffffffffff [0xffe]
        bar 6: mem at 0xffffffffffffffff [0xfffe]

qemu-kvm-0.12.1.2-2.99
(qemu) info qtree
...
dev: virtio-net-pci, id "net0"
        dev-prop: vectors = 3
        dev-prop: indirect_desc = off
        dev-prop: csum = on
        dev-prop: guest_csum = on
        dev-prop: gso = on
        dev-prop: guest_tso4 = on
        dev-prop: guest_tso6 = off
        dev-prop: guest_ecn = off
        dev-prop: guest_ufo = off
        dev-prop: host_tso4 = off
        dev-prop: host_tso6 = off
        dev-prop: host_ecn = off
        dev-prop: host_ufo = off
        dev-prop: mrg_rxbuf = off
        dev-prop: status = off
        dev-prop: ctrl_vq = off
        dev-prop: ctrl_rx = off
        dev-prop: ctrl_vlan = off
        dev-prop: ctrl_rx_extra = off
        dev-prop: mac = 54:52:00:1d:c0:af
        dev-prop: vlan = <null>
        dev-prop: netdev = hostnet0
        bus-prop: addr = 04.0
        bus-prop: romfile = "pxe-virtio.bin"
        bus-prop: rombar = 1
        class Ethernet controller, addr 00:04.0, pci id 1af4:1000 (sub 1af4:0001)
        bar 0: i/o at 0xffffffffffffffff [0x1e]
        bar 1: mem at 0xffffffffffffffff [0xffe]
        bar 6: mem at 0xffffffffffffffff [0xfffe]

Comment 6 releng-rhel@redhat.com 2010-11-10 21:26:42 UTC

Red Hat Enterprise Linux 6.0 is now available and should resolve
the problem described in this bug report. This report is therefore being closed
with a resolution of CURRENTRELEASE. You may reopen this bug report if the
solution does not work for you.