Bug 521514

Summary:	mkinitrd needs to load virtio_pci for KVM
Product:	Red Hat Enterprise Linux 5	Reporter:	Rik van Riel <riel>
Component:	mkinitrd	Assignee:	Peter Jones <pjones>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Release Test Team <release-test-team-automation>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	5.4	CC:	atodorov, ddumas, knoel, ma
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:	2010-07-12 13:24:36 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:

Description Rik van Riel 2009-09-06 16:30:37 UTC

Description of problem:

If a KVM guest is booted from a virtio disk, specified with "scsi_controller virtio_blk" in /etc/modprobe.conf, then mkinitrd should make sure virtio_pci is also loaded.

The kernel module virtio_blk cannot depend on virtio_pci because it can also work with the alternatives virtio_s390 (for s390 kvm) or virtio_lguest (for lguest).  However, RHEL only supports KVM on x86-64, so it would be nice to make it work by default.

Steps to Reproduce:
1. install a KVM guest
2. configure the guest to use virtio, both on the host side and with "scsi_controller virtio_blk" in the guest
3. watch the guest fail to boot
  
Expected results:

It would be really nice if it just worked.

Additional information:

mkinitrd by default does not let the initrd rescan the block devices for the LVM VGs, so changing the block device from emulated IDE to virtio will also break a RHEL 5 guest in other ways.  I'm filing another bug on that now :)

Comment 1 RHEL Program Management 2010-07-02 03:09:19 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 2 Alexander Todorov 2010-07-12 12:32:33 UTC

Rik,
can you be more verbose?

With RHEL5.5 and default install on RHEL6 KVM host the guesat is configured to use virtio by default. The modprobe.conf looks like:
alias scsi_hostadapter ata_piix
alias scsi_hostadapter1 virtio_blk

and the system boots successfully.

Comment 3 Rik van Riel 2010-07-12 12:51:31 UTC

OK, then I guess we fixed the bug between then and now.