Comment 0 for bug 1818645

== Comment: #0 - Satheesh Rajendran <email address hidden> - 2019-02-28 04:38:22 ==
---Problem Description---
Power8 Compat guest(RHEL 7.6) crashes during guest boot with > 256G of memory (kernel/kvm)

Contact Information = <email address hidden>

---uname output---
Host Kernel: 4.15.0-1016-ibm-gt

ii qemu-system-ppc 1:2.11+dfsg-1ubuntu7.8-1ibm3 ppc64el QEMU full system emulation binaries (ppc)

ii libvirt-bin 4.0.0-1ubuntu8.6 ppc64el programs for the libvirt library

Guest kernel: 3.10.0-957.5.1.el7.ppc64le (rhel7.6 zstream)

Machine Type = power9 ppc64le

---Steps to Reproduce---
 1. Boot a power8 compat guest with memory >256G
virsh define avocado-vt-vm1;virsh start --console avocado-vt-vm1 (guest xml sosreport attached)
----Guest crashes while booting

2019-02-28 10:36:44.752+0000: starting up libvirt version: 4.0.0, package: 1ubuntu8.6 (Christian Ehrhardt <email address hidden> Fri, 09 Nov 2018 07:42:01 +0100), qemu version: 2.11.1(Debian 1:2.11+dfsg-1ubuntu7.8-1ibm3), hostname: cs-host-f37-ac922-3.pok.ibm.com
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/qemu-system-ppc64 -name guest=avocado-vt-vm1,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-15-avocado-vt-vm1/master-key.aes -machine pseries-2.11,accel=kvm,usb=off,dump-guest-core=off -m 264192 -realtime mlock=off -smp 256,sockets=256,cores=1,threads=1 -uuid f4e14f88-bf1b-4cc3-b6d6-958d514d6c18 -display none -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-15-avocado-vt-vm1/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot strict=on -device qemu-xhci,id=usb,bus=pci.0,addr=0x3 -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x4 -drive file=/home/sath/avocado-fvt-wrapper/data/avocado-vt/images/rhel76-ppc64le.qcow2,format=qcow2,if=none,id=drive-scsi0-0-0-0 -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 -netdev tap,fd=28,id=hostnet0,vhost=on,vhostfd=30 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:fc:fd:fe,bus=pci.0,addr=0x1 -chardev pty,id=charserial0 -device spapr-vty,chardev=charserial0,id=serial0,reg=0x30000000 -chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/channel/target/domain-15-avocado-vt-vm1/org.qemu.guest_agent.0,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5 -msg timestamp=on
2019-02-28 10:36:44.759+0000: 19598: info : libvirt version: 4.0.0, package: 1ubuntu8.6 (Christian Ehrhardt <email address hidden> Fri, 09 Nov 2018 07:42:01 +0100)
2019-02-28 10:36:44.759+0000: 19598: info : hostname: cs-host-f37-ac922-3
2019-02-28 10:36:44.759+0000: 19598: info : virObjectUnref:350 : OBJECT_UNREF: obj=0x76d594111710
2019-02-28T10:36:44.781703Z qemu-system-ppc64: -chardev pty,id=charserial0: char device redirected to /dev/pts/3 (label charserial0)
2019-02-28T10:36:44.781945Z qemu-system-ppc64: warning: Number of SMP cpus requested (256) exceeds the recommended cpus supported by KVM (128)
2019-02-28T10:36:44.781953Z qemu-system-ppc64: warning: Number of hotpluggable cpus requested (256) exceeds the recommended cpus supported by KVM (128)
2019-02-28 10:37:18.060+0000: shutting down, reason=crashed
2019-02-28T10:37:18.071969Z qemu-system-ppc64: terminating on signal 15 from pid 14056 (/usr/sbin/libvirtd)

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== Comment: #3 - Satheesh Rajendran <email address hidden> - 2019-02-28 04:51:45 ==
Possible Upstream fix: https://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc.git/commit/?h=kvm-ppc-next&id=46dec40fb741f00f1864580130779aeeaf24fb3d