RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1261846 - qemu-kvm-rhev: 64-bit PCI bars may overlap hotplugged memory and vice verse
Summary: qemu-kvm-rhev: 64-bit PCI bars may overlap hotplugged memory and vice verse
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm-rhev
Version: 7.2
Hardware: Unspecified
OS: Unspecified
medium
high
Target Milestone: rc
: ---
Assignee: Igor Mammedov
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2015-09-10 10:02 UTC by Igor Mammedov
Modified: 2015-12-04 16:56 UTC (History)
8 users (show)

Fixed In Version: qemu-kvm-rhev-2.3.0-23.el7
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-12-04 16:56:52 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2015:2546 0 normal SHIPPED_LIVE qemu-kvm-rhev bug fix and enhancement update 2015-12-04 21:11:56 UTC

Description Igor Mammedov 2015-09-10 10:02:36 UTC 
Description of problem:
In QEMU reserved-memory-end tells firmware address from which
it could start treating memory as PCI address space
and map PCI BARs after it to avoid collisions with
RAM.
Currently it is incorrectly pointing to address where
hotplugged memory range starts which could redirect
hotplugged RAM accesses to PCI BARs when firmware
maps them over RAM or vice verse.
Fix this by pointing reserved-memory-end to the end
of memory hotplug area.

Version-Release number of selected component (if applicable):
qemu-kvm-1.5.3-102
Comment 4 Igor Mammedov 2015-09-11 12:49:54 UTC 
Easy way to verify bug,

1: 
/usr/libexec/qemu-kvm  -m 4G,slots=1,maxmem=12G \
   -object memory-backend-ram,id=dimm1,size=1G \
   -device ivshmem,size=1G,shm=ssss \
   -device pc-dimm,id=d1,memdev=dimm1 \
   -monitor stdio -M pc-i440fx-rhel7.2.0

2:
execute in monitor prompt command 'info mtree'

Actual results:
  0000000140000000-000000017fffffff (prio 0, RW): ivshmem.bar2
...
0000000140000000-000000037fffffff (prio 0, RW): hotplug-memory
  0000000140000000-000000017fffffff (prio 0, RW): dimm1

Expected results:
ivshmem.bar2 shouldn't intersect with hotplugged memory
and should start beyond hotplug-memory region range, i.e. after 000000037fffffff

with -M pc-i440fx-rhel7.1.0 Expected result should stay broken like in Actual result.
Comment 5 Igor Mammedov 2015-09-11 13:27:16 UTC 
http://post-office.corp.redhat.com/archives/rhvirt-patches/2015-September/msg00211.html
Comment 6 Miroslav Rezanina 2015-09-15 10:51:15 UTC 
Fix included in qemu-kvm-rhev-2.3.0-23.el7
Comment 7 Pei Zhang 2015-09-16 05:24:57 UTC 
Summary: The results of verification can prove that this bug has been fixed.


Reproduced:
Host:
kernel:3.10.0-316.el7.x86_64
qemu-img-rhev-2.3.0-22.el7.x86_64

Steps:
1.# /usr/libexec/qemu-kvm  -m 4G,slots=1,maxmem=12G \
   -object memory-backend-ram,id=dimm1,size=1G \
   -device ivshmem,size=1G,shm=ssss \
   -device pc-dimm,id=d1,memdev=dimm1 \
   -monitor stdio -M pc-i440fx-rhel7.2.0
(qemu)info mtree
...
      0000000140000000-000000017fffffff (prio 0, RW): ivshmem.bar2
...
  0000000140000000-000000037fffffff (prio 0, RW): hotplug-memory
    0000000140000000-000000017fffffff (prio 0, RW): dimm1

ivshmem.bar2 intersect with hotplug-memory. So this bug is reproduced.



Verified:
Host:
kernel:3.10.0-316.el7.x86_64
qemu-img-rhev-2.3.0-23.el7.x86_64

Scenario 1: -M pc-i440fx-rhel7.2.0
#/usr/libexec/qemu-kvm  -m 4G,slots=1,maxmem=12G \
   -object memory-backend-ram,id=dimm1,size=1G \
   -device ivshmem,size=1G,shm=ssss \
   -device pc-dimm,id=d1,memdev=dimm1 \
   -monitor stdio -M pc-i440fx-rhel7.2.0
(qemu)info mtree
...
    0000000380000000-00000003bfffffff (prio 0, RW): ivshmem.bar2
...
  0000000140000000-000000037fffffff (prio 0, RW): hotplug-memory
    0000000140000000-000000017fffffff (prio 0, RW): dimm1

ivshmem.bar2 doesn't intersect with hotplug-memory and start beyong hotplug-memory.　


Scenario 2: -M pc-i440fx-rhel7.1.0
#/usr/libexec/qemu-kvm  -m 4G,slots=1,maxmem=12G \
   -object memory-backend-ram,id=dimm1,size=1G \
   -device ivshmem,size=1G,shm=ssss \
   -device pc-dimm,id=d1,memdev=dimm1 \
   -monitor stdio -M pc-i440fx-rhel7.1.0
(qemu)info mtree
...
      0000000140000000-000000017fffffff (prio 0, RW): ivshmem.bar2
...
  0000000140000000-000000033fffffff (prio 0, RW): hotplug-memory
    0000000140000000-000000017fffffff (prio 0, RW): dimm1

ivshmem.bar2 intersect with hotplug-memory, it is broken.

According to Comment 4, results of Scenario 1 and Scenario 2 is expected. So this bug has been fixed.
Comment 8 juzhang 2015-09-21 03:05:07 UTC 
According to comment4 and comment5, set this issue as verified.
Comment 10 errata-xmlrpc 2015-12-04 16:56:52 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-2546.html
Note You need to log in before you can comment on or make changes to this bug.