Bug 2034942 - <hint-dedicated> should not require <cpu mode='host-passthrough'> [rhel-8.4.0.z]
Summary: <hint-dedicated> should not require <cpu mode='host-passthrough'> [rhel-8.4.0.z]
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux Advanced Virtualization
Classification: Red Hat
Component: libvirt
Version: 8.4
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: rc
: 8.5
Assignee: Tim Wiederhake
QA Contact: Luyao Huang
URL:
Whiteboard:
Depends On: 1857671
Blocks: 2029343
TreeView+ depends on / blocked
 
Reported: 2021-12-22 14:30 UTC by RHEL Program Management Team
Modified: 2022-01-31 15:29 UTC (History)
13 users (show)

Fixed In Version: libvirt-7.0.0-14.6.el8
Doc Type: Bug Fix
Doc Text:
Cause: When a guest is defined its XML is validated against some hard coded rules. Part of that was a check whether hint-dedicated feature is set if and only if guest cpu model is 'host-passthrough'. But as it turned out, this check is wrong, because all the hint-dedicated feature is available for all cpu models. Consequence: Libvirt denied defining or starting such guest. Fix: The fix consists of removing the problematic check. Result: Our validation is one bad check lighter and users can start their hint-dedicated guests happily.
Clone Of: 1857671
Environment:
Last Closed: 2022-01-31 15:18:50 UTC
Type: ---
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker RHELPLAN-106413 0 None None None 2021-12-22 14:32:38 UTC
Red Hat Product Errata RHSA-2022:0325 0 None None None 2022-01-31 15:19:02 UTC

Comment 6 Luyao Huang 2022-01-13 02:03:19 UTC 
Verify this bug with libvirt-daemon-7.0.0-14.6.module+el8.4.0+13801+378af433.x86_64:

1. prepare a guest which enable hint-dedicated and use host-model cpu mode

# virsh edit q35.xml
...
  <features>
    <acpi/>
    <apic/>
    <pae/>
    <kvm>
      <hint-dedicated state='on'/>
    </kvm>
  </features>
  <cpu mode='host-model' check='partial'/>

Domain 'vm1' XML configuration edited

2. start guest
# virsh start vm1
Domain 'vm1' started

3. check qemu command line:
# ps aux|grep qemu
...kvm-hint-dedicated=on...

And test enable hint-dedicated with custom,host-passthrough cpu mode, got the same result
Comment 8 errata-xmlrpc 2022-01-31 15:18:50 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 (Low: virt:av and virt-devel:av security and bug fix update), 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://access.redhat.com/errata/RHSA-2022:0325
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