Bug 525743

Summary:	Regression between 2.6.29 and 2.6.30 causing qemu.git KVM support to break
Product:	[Fedora] Fedora	Reporter:	Juan Quintela <quintela>
Component:	kernel	Assignee:	Juan Quintela <quintela>
Status:	CLOSED ERRATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	11	CC:	dougsland, gansalmon, itamar, kernel-maint, markmc, mtosatti, virt-maint
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	2.6.30.9-90.fc11	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2009-10-30 17:58:54 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:	480594

Description Juan Quintela 2009-09-25 14:15:42 UTC

Description of problem:

Upstream qemu git worked with 2.6.29.x Fedora kernel.  With new 2.6.30.5-43.fc11
qemu --enable-kvm -loadvm don't work anymore.

Version-Release number of selected component (if applicable):

2.6.30.5-43.fc11

How reproducible:

always

Steps to Reproduce:
1. Boot a guest with qemu-system-x86_64 --enable-kvm .... rest args...
2. in the qemu monitor type: savevm foo
3. Now try to load the snapshot: qemu-system-x86 --enable-kvm -loadvm foo ... rest arguments
  
Actual results:

guest machine loads correctly, but just after load it resets the guest and it restarts.

Expected results:

Execution continues from saved state

Additional info:

upstream qemu.git without --enable-kvm still works (it don't use kvm)
qemu-kvm from F11 updates work
upsntream qemu-kvm.git also work

Comment 1 Juan Quintela 2009-09-25 14:16:14 UTC

I am trying to bisect between 2.6.29 and 2.6.30 what commit caused the breakage

Comment 2 Juan Quintela 2009-09-26 01:28:00 UTC

Reverting this commit from upstream fixes the issue.  Commit was already reverted
in kvm upstream git.


    Revert "KVM: x86: check for cr3 validity in ioctl_set_sregs"
    
    This reverts commit d42a5ebb5ecc66aa692a1141c7ba284ec612e9cc.

Comment 3 Chuck Ebbert 2009-09-27 10:06:59 UTC

Interesting... 2.6.30.6 got the more robust check in mmu_alloc_roots (commit 8986ecc0ef58c96eec48d8502c048f3ab67fd8e2) mentioned in the revert patch but did not get that revert (commit dc7e795e3dd2a763e5ceaa1615f307e808cf3932).

Comment 4 Chuck Ebbert 2009-09-27 10:25:01 UTC

This patch didn't get into 2.6.31.1 either, so is needed for f-12 as well.

Comment 5 Chuck Ebbert 2009-09-28 16:59:06 UTC

Fixed in  2.6.30.8-69

Comment 6 Marcelo Tosatti 2009-10-01 16:10:07 UTC

Chuck,

Revert patch already in -stable queue for .30/.31.

Comment 7 Fedora Update System 2009-10-18 01:57:02 UTC

kernel-2.6.30.9-90.fc11 has been submitted as an update for Fedora 11.
http://admin.fedoraproject.org/updates/kernel-2.6.30.9-90.fc11

Comment 8 Fedora Update System 2009-10-27 06:47:00 UTC

kernel-2.6.30.9-90.fc11 has been pushed to the Fedora 11 stable repository.  If problems still persist, please make note of it in this bug report.