Bug 492868 - Xen guest kernel advertises absolute mouse pointer feature which it is incapable of setting up correctly
Xen guest kernel advertises absolute mouse pointer feature which it is incap...
Status: CLOSED ERRATA
Product: Red Hat Enterprise Linux 4
Classification: Red Hat
Component: kernel-xen (Show other bugs)
4.9
All Linux
low Severity medium
: rc
: ---
Assigned To: Andrew Jones
Virtualization Bugs
: FutureFeature
Depends On:
Blocks: 458302
  Show dependency treegraph
 
Reported: 2009-03-30 09:35 EDT by Daniel Berrange
Modified: 2016-04-26 12:39 EDT (History)
7 users (show)

See Also:
Fixed In Version:
Doc Type: Enhancement
Doc Text:
Story Points: ---
Clone Of: 492866
Environment:
Last Closed: 2011-02-16 11:03:46 EST
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
CRM:
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---


Attachments (Terms of Use)
Patch to change PVFB not to select abs. pointer (2.89 KB, patch)
2009-07-31 11:08 EDT, Andrew Jones
no flags Details | Diff

  None (edit)
Description Daniel Berrange 2009-03-30 09:35:13 EDT
+++ This bug was initially created as a clone of Bug #492866 +++

Description of problem:
The PVFB graphics driver includes a paravirt mouse input device. When talking to the host OS over xenbus, it advertises that it supports absolute coordinate mode. RHEL-5 userspace is incapable of actually running the mouse in absolute mode by default though, so out of the box the guest OS is doing abs -> rel coordinate conversion.  This in turn causes problems for anyone connecting to the guest OS using the VNC server in the host OS because their mouse pointer will likely hit an invisible wall.

The absolute mouse coordinate feature should be disabled by default in RHEL-5 guest kernels. A boot parameter, or other tunable should be provided to allow absolute mode to be re-enabled  if the admin has manually configured an xorg.conf that supports it.

Version-Release number of selected component (if applicable):
kernel-xen-2.6.18-128.el5

How reproducible:
Always

Steps to Reproduce:
1. Boot RHEL-5 guest
2. On host run xenstore-ls /local/domain/0/backend/vkbd
3.
  
Actual results:
  feature-abs-pointer = "1"


Expected results:
  feature-abs-pointer = "0"


Additional info:
Comment 1 Markus Armbruster 2009-04-16 14:03:43 EDT
Patch for RHEL-5 applies fine.
Comment 2 Andrew Jones 2009-07-31 11:08:26 EDT
Created attachment 355824 [details]
Patch to change PVFB not to select abs. pointer

Attached backported patch.
Comment 4 Vivek Goyal 2009-08-25 15:23:07 EDT
Committed in 89.11.EL . RPMS are available at http://people.redhat.com/vgoyal/rhel4/
Comment 6 Binbin Yu 2010-12-20 02:19:53 EST
Verification failed on,
host: rhel5.5-i386
kernel-xen-2.6.18-233.el5
xen-3.0.3-120.el5
guest: rhel4.8 i386 pv, with kernel updated to 89.32.EL


Steps to Reproduce:
1. Boot RHEL-4.8 PV guest, and update the guest kernel to 89.32.EL
2. Restart the guest
3. On host run xenstore-ls /local/domain/0/backend/vkbd


Actual results:
  feature-abs-pointer = "1"


Expected results:
  feature-abs-pointer = "0"


Additional info:
1. On the same environment, I start a rhel5u5-32-pv guest and run the same command, also feature-abs-pointer = "1"
Comment 7 Binbin Yu 2010-12-20 02:43:18 EST
Additional info:
2. On the same environment, I even update the rhel4.8 guest' kernel to 93.EL, and also get feature-abs-pointer = "1".
3. On the same environment, I even update the rhel5.5 guest kernel-xen to kernel-xen-2.6.18-233, also feature-abs-pointer = "1".
Comment 8 Binbin Yu 2010-12-21 21:13:21 EST
Hi, Andrew, do you think this bug has been patched and fixed in rhel4.9(93.EL) ?
Comment 9 Paolo Bonzini 2010-12-22 04:51:34 EST
Hi Binbin, you need to search for "request-abs-pointer".  It should be "1" without the patch and "0" or absent with the patch.  See bug 492866 comment #11.
Comment 10 Paolo Bonzini 2010-12-22 04:56:00 EST
(See also bug 492866 comment #1 which explains that the original description of the bug was not accurate):

> Xenstore node /local/domain/0/backend/vkbd shows whether the backend (host)
> offered the feature.  To see whether the frontend (guest) accepted it, which is
> what you want here, you run
> 
> # xenstore-read /local/domain/$DOMID/device/vkbd/0/request-abs-pointer
Comment 11 Binbin Yu 2010-12-23 00:11:44 EST
test steps:
host: rhel5.5-i386 and x86_64
kernel-xen-2.6.18-231.el5
xen-3.0.3-120.el5
guest: rhel4.9 pv (by updating rhel4.8 guest kernel to 93.ELxenU)

1. Boot RHEL-4.8 PV guest, and update the guest kernel to 93.ELxenU, reboot
2. create the rhel4.9 pv guest
3. On host run xenstore-read /local/domain/$guestid/device/vkbd/0/request-abs-pointer


Reproduce on rhel4.8 pv guest with kernel 89.ELxenU:
[HOST]# xenstore-read /local/domain/1/device/vkbd/0/request-abs-pointer
1


Verified on rhel4.9 pv guest with kernel 93.ELxenU:
[host]# xenstore-read /local/domain/3/device/vkbd/0/request-abs-pointer
xenstore-read: couldn't read path /local/domain/3/device/vkbd/0/request-abs-pointer


So set this bug be VERIFIED
Comment 12 errata-xmlrpc 2011-02-16 11:03:46 EST
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-2011-0263.html

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