From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 30 Jul 2015 11:30:03 +0000 (+0200)
Subject: Merge tag 'kvm-s390-master-20150730' of git://git.kernel.org/pub/scm/linux/kernel... 
X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~11852^2~1
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=7307f70c6d525aa050d3027035215fb5473aa1bb;p=mirror_ubuntu-focal-kernel.git

Merge tag 'kvm-s390-master-20150730' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-master

KVM: s390: bugfix for kvm/master (4.2)

Here is a bugfix for a regression that was introduced after 4.1
with the commit commit 785dbef407d8 ("KVM: s390: optimize round
trip time in request handling"). After lots of cpu hotplugs in the
guest (online/offline) sometimes a guest CPU did loop within host
KVM code. Reason was that PROG_REQUEST was set in the sie control
block, but no request was pending. This made commit 785dbef407d8
the suspect and changing that area to always reset PROG_REQUEST
did indeed fix the problem.

Special thanks to David Hildenbrand, who helped understanding the
exact sequence that led to the problem.
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7307f70c6d525aa050d3027035215fb5473aa1bb