Bug 636494
| Summary: | -cpu check does not correctly enforce CPUID items | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Daniel Berrangé <berrange> |
| Component: | qemu-kvm | Assignee: | john cooper <john.cooper> |
| Status: | CLOSED ERRATA | QA Contact: | Virtualization Bugs <virt-bugs> |
| Severity: | medium | Docs Contact: | |
| Priority: | low | ||
| Version: | 6.1 | CC: | bcao, mhusnain, michen, mjenner, mkenneth, nobody, snagar, tburke, virt-maint |
| Target Milestone: | rc | ||
| Target Release: | 6.1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | qemu-kvm-0.12.1.2-2.132.el6 | Doc Type: | Bug Fix |
| Doc Text: |
Previously, the VMX and SVM CPU features were not applied in a uniform manner. Additionally, the check and enforce options were incorrectly validated, which caused confusion for guests in specific scenarios. This is now fixed to uniformly disallow VMX for all instances and to allow SVM only if nested kvm is in effect. This fix removes the confusions for guests that occurs due to unintentional VMX and SVM exposure.
-- Comments --
Perhaps a more concise summary of the issue would be:
"VMX and SVM cpuid flags were not correctly screened and
could be passed to the guest even in the case they did not
exist on the host or could not be supported by kvm. As
this has the potential to confuse a guest, this fix
assures these cpuid flags are visible only when
appropriate and warns an interested user in the event
they have been requested but cannot be made available."
|
Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2011-05-19 11:33:24 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: | 580954 | ||
|
Description
Daniel Berrangé
2010-09-22 11:27:15 UTC
Case addressed by the following patch (resolution detail within): http://post-office.corp.redhat.com/archives/rhvirt-patches/2010-October/msg00141.html Note "enforce" implies "check" and the latter needn't accompany the former. Reproduced on qemu-kvm-0.12.1.2-2.131.el6 Verified on qemu-kvm-0.12.1.2-2.144.el6 Actual Results: #/usr/libexec/qemu-kvm -cpu Penryn,+vmx,check,enforce warning: host cpuid 0000_0001:ecx flag restricted to guest 'vmx' [0x00000020] Unable to support requested x86 CPU definition #/usr/libexec/qemu-kvm -cpu Penryn,+svm,check,enforce warning: host cpuid 8000_0001:ecx lacks requested flag 'svm' [0x00000004] Unable to support requested x86 CPU definition Based on above ,this issue has already been fixed. Add CCFR.
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:
Cause
Cpu features "vmx" and "svm" are not validated correctly for
"check" and "enforce" options.
Consequence
These flags may confuse a guest in certain scenarios if exposed.
Also "check" and "enforce" semantics should be uniformly
applied.
Fix
Disallow "vmx" in all cases and "svm" only if nested kvm is
in effect.
Result
Elimination of guest confusion related to unintententional exposure
of "vmx' and "svm".
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:
@@ -1,16 +1 @@
-Cause
+Previously, the VMX and SVM CPU features were not applied in a uniform manner. Additionally, the check and enforce options were incorrectly validated, which caused confusion for guests in specific scenarios. This is now fixed to uniformly disallow VMX for all instances and to allow SVM only if nested kvm is in effect. This fix removes the confusions for guests that occurs due to unintentional VMX and SVM exposure.- Cpu features "vmx" and "svm" are not validated correctly for
-"check" and "enforce" options.
-
-Consequence
- These flags may confuse a guest in certain scenarios if exposed.
-Also "check" and "enforce" semantics should be uniformly
-applied.
-
-Fix
- Disallow "vmx" in all cases and "svm" only if nested kvm is
-in effect.
-
-Result
- Elimination of guest confusion related to unintententional exposure
-of "vmx' and "svm".
tech notes update.
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 +1,13 @@
-Previously, the VMX and SVM CPU features were not applied in a uniform manner. Additionally, the check and enforce options were incorrectly validated, which caused confusion for guests in specific scenarios. This is now fixed to uniformly disallow VMX for all instances and to allow SVM only if nested kvm is in effect. This fix removes the confusions for guests that occurs due to unintentional VMX and SVM exposure.+Previously, the VMX and SVM CPU features were not applied in a uniform manner. Additionally, the check and enforce options were incorrectly validated, which caused confusion for guests in specific scenarios. This is now fixed to uniformly disallow VMX for all instances and to allow SVM only if nested kvm is in effect. This fix removes the confusions for guests that occurs due to unintentional VMX and SVM exposure.
+
+-- Comments --
+
+Perhaps a more concise summary of the issue would be:
+
+"VMX and SVM cpuid flags were not correctly screened and
+could be passed to the guest even in the case they did not
+exist on the host or could not be supported by kvm. As
+this has the potential to confuse a guest, this fix
+assures these cpuid flags are visible only when
+appropriate and warns an interested user in the event
+they have been requested but cannot be made available."
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-2011-0534.html 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-2011-0534.html |