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Bug 665972

Summary: ISVM bit (ECX:31) for CPUID 0x00000001 is missing for HVM on AMD
Product: Red Hat Enterprise Linux 5 Reporter: Jinxin Zheng <jzheng>
Component: kernel-xenAssignee: Paolo Bonzini <pbonzini>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: low    
Version: 5.6CC: drjones, herrold, mshao, qcai, qwan, xen-maint
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
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Clone Of: Environment:
Last Closed: 2011-07-21 10:28:38 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:
Attachments:
Description Flags
fix for the bug none

Description Jinxin Zheng 2010-12-28 07:36:19 UTC 
Description of problem:
Bug 573771 adds IsVM test support for guest. However this is found not working for HVM on an AMD CPU.

Version-Release number of selected component (if applicable):
kernel-xen-2.6.18-238.el5

How reproducible:
Always on AMD.

Steps to Reproduce:
In the HVM guest, run the code attached in bug 573771. It outputs

HVM guest, hypervisor present bit *NOT* set

or

$ x86info -r | grep 0x00000001
eax in: 0x00000001, eax = 00100f23 ebx = 02010800 ecx = 00002001 edx = 0789fbff

see bit 31 of ecx is not set.
Comment 1 Paolo Bonzini 2011-01-05 08:21:19 UTC 
Created attachment 471812 [details]
fix for the bug

Alternatively, one could backport c/s 16990 from upstream.
Comment 2 RHEL Program Management 2011-02-01 16:50:59 UTC 
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.
Comment 4 Jarod Wilson 2011-02-09 14:57:27 UTC 
in kernel-2.6.18-243.el5
You can download this test kernel (or newer) from http://people.redhat.com/jwilson/el5

Detailed testing feedback is always welcomed.
Comment 6 Qixiang Wan 2011-02-24 06:39:27 UTC 
Test with kernel 2.6.18-243.el5xen, ISVM bit is set on AMD cpu now, run the program attached in but 573771 comment 1 will get the output:

HVM guest, hypervisor present bit set

change to VERIFIED.
Comment 8 errata-xmlrpc 2011-07-21 10:28:38 UTC 
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-2011-1065.html