Bug 489274

Summary: [RHEL5.3 Xen]: Cannot attach > 16 PV disks using PV-on-HVM drivers
Product: Red Hat Enterprise Linux 5 Reporter: Chris Lalancette <clalance>
Component: kernel-xenAssignee: Chris Lalancette <clalance>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: low    
Version: 5.3CC: ddutile, dzickus, james.brown, xen-maint
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2009-09-02 08:55:11 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description Flags
Backport of xen-unstable c/s 18266 and 19266 that seems to fix the problem none

Description Chris Lalancette 2009-03-09 09:42:56 UTC 
Description of problem:
While attempting to do some testing on a RHEL-5.3 guest, I wanted to attach 32 disks to an i386 guest.  I used the following command 30 times:

xm block-attach rhel5fv_i386 tap:aio:/var/lib/xen/images/disk.img /dev/xvd? w

Devices xvda->xvdq attached just fine, and I was able to use them in the guest.  However, devices beyond that (/dev/xvdr and higher) did not show up in the guest.  I also performed this test on a PV i386 guest, a PV x86_64 guest, and an FV x86_64 guest; in all 3 of those cases, it worked just fine.  So this seems to be particular to 32-bit FV on 64-bit dom0.
Comment 1 Chris Lalancette 2009-03-09 09:44:18 UTC 
This recent upstream discussion may also be relevant here:

http://lists.xensource.com/archives/html/xen-devel/2009-03/msg00146.html
Comment 4 Chris Lalancette 2009-03-27 14:43:09 UTC 
Created attachment 337016 [details]
Backport of xen-unstable c/s 18266 and 19266 that seems to fix the problem
Comment 7 Don Zickus 2009-04-16 18:39:39 UTC 
in kernel-2.6.18-139.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.
Comment 13 errata-xmlrpc 2009-09-02 08:55:11 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-2009-1243.html