Bug 1018897

Summary:	Nodedev-detach fails for devices without driver
Product:	[Community] Virtualization Tools	Reporter:	Vlastimil Holer <vlastimil.holer>
Component:	libvirt	Assignee:	Libvirt Maintainers <libvirt-maint>
Status:	CLOSED NEXTRELEASE	QA Contact:
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	unspecified	CC:	acathrow, dyuan, honzhang, mprivozn, xuzhang
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:
Clones:	1019387 (view as bug list)		Environment:
Last Closed:	2013-11-04 16:33:24 UTC	Type:	Bug
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:	1028629

Description Vlastimil Holer 2013-10-14 16:10:56 UTC

Description of problem:
When device is not managed by any driver (real or stub), sysfs device entries doesn't contain "driver" symlink. Domain with PCI device in managed mode fails to start due to missing "driver" symlink on sysfs. Libvirt nodedev-detach fails as well.

Version-Release number of selected component (if applicable):
1.1.3

How reproducible:

Steps to Reproduce:
1. find device without driver
2. virsh nodedev-detach pci_...

Actual results:
Device must be manually assigned to stub driver.

Expected results:
Device is assigned to stub driver automatically.

Additional info:
# ls -a /sys/bus/pci/devices/0000:03:00.0/
. enable msi_bus resource2
.. firmware_node numa_node resource2_wc
broken_parity_status index power subsystem
class irq remove subsystem_device
config label rescan subsystem_vendor
consistent_dma_mask_bits local_cpulist reset uevent
device local_cpus resource vendor
dma_mask_bits modalias resource0 vpd

# virsh create deployment.0
setlocale: No such file or directory
error: Failed to create domain from deployment.0
error: internal error: Invalid device 0000:03:00.0 driver file /sys/bus/pci/devices/0000:03:00.0/driver is not a symlink

# virsh nodedev-detach pci_0000_03_00_0
setlocale: No such file or directory
error: Failed to detach device pci_0000_03_00_0
error: internal error: Invalid device 0000:03:00.0 driver file /sys/bus/pci/devices/0000:03:00.0/driver is not a symlink

# modprobe pci_stub ids=15b3:1003
# virsh nodedev-detach pci_0000_03_00_0
Device pci_0000_03_00_0 detached

Comment 1 Michal Privoznik 2013-11-04 16:33:24 UTC

I've just pushed patch to upstream to fix this issue:

commit df4283a55bf3516b333352e2052dbe3317936953
Author:     Michal Privoznik <mprivozn>
AuthorDate: Thu Oct 31 10:32:58 2013 +0000
Commit:     Michal Privoznik <mprivozn>
CommitDate: Mon Nov 4 17:28:51 2013 +0100

    virpci: Don't error on unbinded devices
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1018897
    
    If a PCI deivce is not binded to any driver (e.g. there's yet no PCI
    driver in the linux kernel) but still users want to passthru the device
    we fail the whole operation as we fail to resolve the 'driver' link
    under the PCI device sysfs tree. Obviously, this is not a fatal error
    and it shouldn't be error at all.
    
    Signed-off-by: Michal Privoznik <mprivozn>

v1.1.4-15-gdf4283a