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Bug 570056

Summary: hvm guest will always restart when VCPU bound to specific CPU
Product: Red Hat Enterprise Linux 5 Reporter: Yewei Shao <mshao>
Component: kernel-xenAssignee: Xen Maintainance List <xen-maint>
Status: CLOSED DUPLICATE QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: low    
Version: 5.5CC: drjones, leiwang, mrezanin, pbonzini, rlerch, xen-maint, yuzhang
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2010-06-25 11:38:11 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: 540752    
Attachments:
Description Flags
The config file
none
dmesg
none
Bug earlyprink screenshot none

Description Yewei Shao 2010-03-03 05:32:39 UTC 
Description of problem:
When bind VCPU to specific CPU (via cpus parameter (cpus = "0") in config
file), the hvm guest will always restart automatically and can not boot up successfully. Please use the config file that in attachment to reproduce the bug.

Version-Release number of selected component (if applicable):
xen-3.0.3-105.el5

How reproducible:
Always

Steps to Reproduce:
1.Start a guest with cpus="0":
   # xm cr $guest cpus="0" vcpus=4
2.
3.
  
Actual results:
The guest will always restart automatically and can not boot up successfully.

Expected results:
The guest should boot up successfully.

Additional info:
Comment 1 Yewei Shao 2010-03-03 05:35:02 UTC 
Created attachment 397475 [details]
The config file
Comment 2 Yewei Shao 2010-03-03 05:35:22 UTC 
Created attachment 397476 [details]
dmesg
Comment 4 Miroslav Rezanina 2010-03-11 09:39:21 UTC 
This is kernel bz. There's similiar bug filled against pv guest - bz #541840. 

CPU's binding is passed to guest correctly. It works for single vcpu on single cpu or multiple vcpus on multiple cpus. I will attach screenshot of earlyprints.

Reassign to kernel-xen
Comment 5 Miroslav Rezanina 2010-03-11 09:40:46 UTC 
Created attachment 399298 [details]
Bug earlyprink screenshot
Comment 6 Andrew Jones 2010-03-11 14:07:46 UTC 
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.

New Contents:
Xen guests will not boot with a configuration that binds multiple vcpus to a single cpu.
Comment 8 Ryan Lerch 2010-03-23 03:41:36 UTC 
Technical note updated. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.

Diffed Contents:
@@ -1 +1 @@
-Xen guests will not boot with a configuration that binds multiple vcpus to a single cpu.+Xen guests will not boot using configurations that bind multiple virtualized CPUs to a single CPU.
Comment 9 Paolo Bonzini 2010-06-02 13:23:49 UTC 
If we want to forbid this configuration, this can simply be a dup of bug 541840.
Comment 10 Paolo Bonzini 2010-06-25 11:38:11 UTC 
Since this is what we're doing in bug 541840 (and it makes no sense to forbid PV but allow HVM), marking as dup.

*** This bug has been marked as a duplicate of bug 541840 ***
Comment 11 Paolo Bonzini 2011-07-14 08:03:20 UTC 
The duplicate bug was fixed, removing technical notes.
Comment 12 Paolo Bonzini 2011-07-14 08:03:20 UTC 
Deleted Technical Notes Contents.

Old Contents:
Xen guests will not boot using configurations that bind multiple virtualized CPUs to a single CPU.