fix vnc screen corruption bugs and viewer exits
Fixes "rect too big" on rapidly changing output or slow connections
add two missing cirrus_update_memory_access
Said to fix possible segfaults in qemu, safe
Right, this is good to have when somebody is using VNC directly instead of virt-manager or any GTK-VNC based tool so I'm going to work on this one.
Created attachment 471483 [details]
I had started backporting the patches so here they are. If you want to test them (Windows guests on high latency connections are good) and post them, I'm happy to pass the bug to you
This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated in the
current release, Red Hat is unfortunately unable to address this
request at this time. Red Hat invites you to ask your support
representative to propose this request, if appropriate and relevant,
in the next release of Red Hat Enterprise Linux.
This request was erroneously denied for the current release of
Red Hat Enterprise Linux. The error has been fixed and this
request has been re-proposed for the current release.
Fix built into xen-3.0.3-126.el5
Failed for test with latest xen-3.0.3-131.el5, still can repro the "rect too big" issue with xen-131.
Procedure to verify:
1. Install host and install it with xen-125 and kernel-2.6.18-262, the last build before the fix.
2. create a winxp 32 hvm guest
3. connect to the xen host with vncviewer on my notebook which connects to the network with VNC( in order to create a low bandwidth environment of 100~400kbps), play some animation in the windows guest, e.g. "Tour windows XP" from start menu or some movie.
4. random move the mouse in the VM and after 2~5 min, it will got "rect too big" error.
After I upgrade the xen to xen-3.0.3-131, repeat the above steps and I still can get "rect too big" error.
Please check the attached screenshot and log files
Created attachment 500424 [details]
screenshot for the repro
Created attachment 500425 [details]
Created attachment 500426 [details]
qemu-dm log before fix
Created attachment 500427 [details]
qemu-dm log after fix
As fixing the problem is not trivial and we're late in 5.7 testing phase, fixing the bug is moved to 5.8
Even the patch in #1 improves vnc handling, problem with too big rect still exists. Solving this issue require too invasive changes for current state of rhel xen. As this is internal reported problem, we will notfix it.