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Created attachment 1524472 [details]
XML of guest

Description of problem:
RT guest fails to reboot in RT host.

Version-Release number of selected component (if applicable):
3.10.0-993.rt56.950.el7.x86_64
qemu-kvm-rhev-2.12.0-21.el7.x86_64
libvirt-4.5.0-10.el7.x86_64

How reproducible:
2/2

Steps to Reproduce:
1. Install a rhel7.7 host and setup rt environment.

3. Install a rhel7.7 guest.

4. In guest, do rt setup, then shutdown it.

5. Boot rt guest, fail.


Actual results:
RT guest fails to boot.

Expected results:
RT guest should boot successfully.

Additional info:
1. If removing below line from XML, guest can boot successfully. 
<vcpusched priority="1" scheduler="fifo" vcpus="0-1" />

2. This should be regression bug.
kernel-rt-3.10.0-993.rt56.948.el7.x86_64 works well.

3. Set this bug critical priority because it blocks all rhel7.7 kvm-rt testing.

The patch that fixes the following bug:

https://bugzilla.redhat.com/show_bug.cgi?id=1554851

Fixes this problem.

Jaroslav, can you please include it in the next RHEL-7.7 tuned update? 

TIA.

Created attachment 1526854 [details]
tuned_isolate_vcpu_thread_only.patch

To fix the bug without a new tuned package:

# cd /usr/lib/tuned/realtime-virtual-host/

# patch -p3 < ~/tuned_isolate_vcpu_thread_only.patch

And restart tuned.

(In reply to Marcelo Tosatti from comment #8)
> To fix the bug without a new tuned package:
> 
> # cd /usr/lib/tuned/realtime-virtual-host/
> 
> # patch -p3 < ~/tuned_isolate_vcpu_thread_only.patch
> 
> And restart tuned.

Applying this tuned patch as a workaround, the rt guest can boot up well. Thanks Marcelo.


Best regards,
Pei

I am closing this as a dupe of bug 1554851, because it's resolved by the same patch.

*** This bug has been marked as a duplicate of bug 1554851 ***