I am experiencing the same thing as tstrike on bug #1813165 on the qemu launchpad (https://bugs.launchpad.net/qemu/+bug/1813165).

When I create a new VM, it quickly goes into a paused state and never seems to start working. Log shows emulation failure.

2020-03-15 18:46:33.010+0000: starting up libvirt version: 6.0.0, package: 0ubuntu5 (Christian Ehrhardt <email address hidden> Tue, 10 Mar 2020 08:58:04 +0100), qemu version: 4.2.0Debian 1:4.2-3ubuntu2, kernel: 5.4.0-14-generic, hostname: hood-vmh-1
LC_ALL=C \
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin \
HOME=/var/lib/libvirt/qemu/domain-1-plex \
XDG_DATA_HOME=/var/lib/libvirt/qemu/domain-1-plex/.local/share \
XDG_CACHE_HOME=/var/lib/libvirt/qemu/domain-1-plex/.cache \
XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain-1-plex/.config \
QEMU_AUDIO_DRV=spice \
/usr/bin/qemu-system-x86_64 \
-name guest=plex,debug-threads=on \
-S \
-object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-1-plex/master-key.aes \
-machine pc-q35-4.2,accel=kvm,usb=off,vmport=off,dump-guest-core=off \
-cpu Nehalem-IBRS,vme=on,vmx=on,x2apic=on,tsc-deadline=on,hypervisor=on,arat=on,tsc-adjust=on,umip=on,stibp=on,arch-capabilities=on,ssbd=on,rdtscp=on,ibpb=on,amd-ssbd=on,skip-l1dfl-vmentry=on \
-m 8196 \
-overcommit mem-lock=off \
-smp 4,sockets=4,cores=1,threads=1 \
-uuid efa551c2-9863-42ab-87ed-fd0010d7a9db \
-no-user-config \
-nodefaults \
-chardev socket,id=charmonitor,fd=31,server,nowait \
-mon chardev=charmonitor,id=monitor,mode=control \
-rtc base=utc,driftfix=slew \
-global kvm-pit.lost_tick_policy=delay \
-no-hpet \
-no-reboot \
-global ICH9-LPC.disable_s3=1 \
-global ICH9-LPC.disable_s4=1 \
-boot strict=on \
-device pcie-root-port,port=0x10,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x2 \
-device pcie-root-port,port=0x11,chassis=2,id=pci.2,bus=pcie.0,addr=0x2.0x1 \
-device pcie-root-port,port=0x12,chassis=3,id=pci.3,bus=pcie.0,addr=0x2.0x2 \
-device pcie-root-port,port=0x13,chassis=4,id=pci.4,bus=pcie.0,addr=0x2.0x3 \
-device pcie-root-port,port=0x14,chassis=5,id=pci.5,bus=pcie.0,addr=0x2.0x4 \
-device pcie-root-port,port=0x15,chassis=6,id=pci.6,bus=pcie.0,addr=0x2.0x5 \
-device ich9-usb-ehci1,id=usb,bus=pcie.0,addr=0x1d.0x7 \
-device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pcie.0,multifunction=on,addr=0x1d \
-device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pcie.0,addr=0x1d.0x1 \
-device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pcie.0,addr=0x1d.0x2 \
-device virtio-serial-pci,id=virtio-serial0,bus=pci.2,addr=0x0 \
-blockdev '{"driver":"file","filename":"/VMs/images/plex/plex.qcow2","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"}' \
-blockdev '{"node-name":"libvirt-2-format","read-only":false,"driver":"qcow2","file":"libvirt-2-storage","backing":null}' \
-device virtio-blk-pci,scsi=off,bus=pci.3,addr=0x0,drive=libvirt-2-format,id=virtio-disk0,bootindex=2 \
-blockdev '{"driver":"file","filename":"/VMs/isos/ubuntu-bionic-mini.iso","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}' \
-blockdev '{"node-name":"libvirt-1-format","read-only":true,"driver":"raw","file":"libvirt-1-storage"}' \
-device ide-cd,bus=ide.0,drive=libvirt-1-format,id=sata0-0-0,bootindex=1 \
-netdev tap,fd=33,id=hostnet0,vhost=on,vhostfd=34 \
-device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:9f:2b:21,bus=pci.1,addr=0x0 \
-chardev pty,id=charserial0 \
-device isa-serial,chardev=charserial0,id=serial0 \
-chardev socket,id=charchannel0,fd=35,server,nowait \
-device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0 \
-chardev spicevmc,id=charchannel1,name=vdagent \
-device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=com.redhat.spice.0 \
-device usb-tablet,id=input0,bus=usb.0,port=1 \
-spice port=5900,addr=127.0.0.1,disable-ticketing,image-compression=off,seamless-migration=on \
-device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,max_outputs=1,bus=pcie.0,addr=0x1 \
-device ich9-intel-hda,id=sound0,bus=pcie.0,addr=0x1b \
-device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 \
-chardev spicevmc,id=charredir0,name=usbredir \
-device usb-redir,chardev=charredir0,id=redir0,bus=usb.0,port=2 \
-chardev spicevmc,id=charredir1,name=usbredir \
-device usb-redir,chardev=charredir1,id=redir1,bus=usb.0,port=3 \
-device virtio-balloon-pci,id=balloon0,bus=pci.4,addr=0x0 \
-object rng-random,id=objrng0,filename=/dev/urandom \
-device virtio-rng-pci,rng=objrng0,id=rng0,bus=pci.5,addr=0x0 \
-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \
-msg timestamp=on
char device redirected to /dev/pts/1 (label charserial0)
2020-03-15T18:46:33.106365Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48FH).vmx-exit-load-perf-global-ctrl [bit 12]
2020-03-15T18:46:33.106430Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(490H).vmx-entry-load-perf-global-ctrl [bit 13]
2020-03-15T18:46:33.108205Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48FH).vmx-exit-load-perf-global-ctrl [bit 12]
2020-03-15T18:46:33.108221Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(490H).vmx-entry-load-perf-global-ctrl [bit 13]
2020-03-15T18:46:33.109232Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48FH).vmx-exit-load-perf-global-ctrl [bit 12]
2020-03-15T18:46:33.109247Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(490H).vmx-entry-load-perf-global-ctrl [bit 13]
2020-03-15T18:46:33.110399Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(48FH).vmx-exit-load-perf-global-ctrl [bit 12]
2020-03-15T18:46:33.110414Z qemu-system-x86_64: warning: host doesn't support requested feature: MSR(490H).vmx-entry-load-perf-global-ctrl [bit 13]
KVM internal error. Suberror: 1
emulation failure
EAX=00000000 EBX=00000000 ECX=000086d4 EDX=00000000
ESI=00000000 EDI=00000000 EBP=000086d4 ESP=00006d7c
EIP=00007acf EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =0000 00000000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     000f6200 00000037
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000000
Code=b8 90 d9 00 00 66 e8 6b f7 ff ff 66 b8 0a 00 00 00 e9 61 f2 <f3> 0f 1e fb 66 57 66 56 66 53 66 53 66 89 c7 67 66 89 14 24 66 89 ce 66 e8 15 f8 ff ff 88


This is a fairly clean install of 20.04, and I was planning to install an 18.04 guest to run plex.

# kvm-ok
INFO: /dev/kvm exists
KVM acceleration can be used
# df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            9.8G     0  9.8G   0% /dev
tmpfs           2.0G  1.6M  2.0G   1% /run
/dev/sda3       2.6T  2.9G  2.5T   1% /
tmpfs           9.8G     0  9.8G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           9.8G     0  9.8G   0% /sys/fs/cgroup
/dev/loop0       54M   54M     0 100% /snap/lxd/11348
/dev/loop1       92M   92M     0 100% /snap/core/8689
/dev/sdb1       2.7T  193M  2.6T   1% /VMs
tmpfs           2.0G     0  2.0G   0% /run/user/1000
# cat /sys/module/kvm_intel/parameters/nested
Y
root@hood-vmh-1:/home/jon# rmmod kvm_intel
root@hood-vmh-1:/home/jon# modprobe kvm_intel nested=0
# cat /sys/module/kvm_intel/parameters/nested
N
# tail -n 60 /var/log/libvirt/qemu/plex.log
-global ICH9-LPC.disable_s4=1 \
-boot strict=on \
-device pcie-root-port,port=0x10,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x2 \
-device pcie-root-port,port=0x11,chassis=2,id=pci.2,bus=pcie.0,addr=0x2.0x1 \
-device pcie-root-port,port=0x12,chassis=3,id=pci.3,bus=pcie.0,addr=0x2.0x2 \
-device pcie-root-port,port=0x13,chassis=4,id=pci.4,bus=pcie.0,addr=0x2.0x3 \
-device pcie-root-port,port=0x14,chassis=5,id=pci.5,bus=pcie.0,addr=0x2.0x4 \
-device pcie-root-port,port=0x15,chassis=6,id=pci.6,bus=pcie.0,addr=0x2.0x5 \
-device ich9-usb-ehci1,id=usb,bus=pcie.0,addr=0x1d.0x7 \
-device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pcie.0,multifunction=on,addr=0x1d \
-device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pcie.0,addr=0x1d.0x1 \
-device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pcie.0,addr=0x1d.0x2 \
-device virtio-serial-pci,id=virtio-serial0,bus=pci.2,addr=0x0 \
-blockdev '{"driver":"file","filename":"/VMs/images/plex/plex.qcow2","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"}' \
-blockdev '{"node-name":"libvirt-2-format","read-only":false,"driver":"qcow2","file":"libvirt-2-storage","backing":null}' \
-device virtio-blk-pci,scsi=off,bus=pci.3,addr=0x0,drive=libvirt-2-format,id=virtio-disk0,bootindex=1 \
-device ide-cd,bus=ide.0,id=sata0-0-0 \
-netdev tap,fd=33,id=hostnet0,vhost=on,vhostfd=34 \
-device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:9f:2b:21,bus=pci.1,addr=0x0 \
-chardev pty,id=charserial0 \
-device isa-serial,chardev=charserial0,id=serial0 \
-chardev socket,id=charchannel0,fd=35,server,nowait \
-device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0 \
-chardev spicevmc,id=charchannel1,name=vdagent \
-device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=com.redhat.spice.0 \
-device usb-tablet,id=input0,bus=usb.0,port=1 \
-spice port=5900,addr=127.0.0.1,disable-ticketing,image-compression=off,seamless-migration=on \
-device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,max_outputs=1,bus=pcie.0,addr=0x1 \
-device ich9-intel-hda,id=sound0,bus=pcie.0,addr=0x1b \
-device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 \
-chardev spicevmc,id=charredir0,name=usbredir \
-device usb-redir,chardev=charredir0,id=redir0,bus=usb.0,port=2 \
-chardev spicevmc,id=charredir1,name=usbredir \
-device usb-redir,chardev=charredir1,id=redir1,bus=usb.0,port=3 \
-device virtio-balloon-pci,id=balloon0,bus=pci.4,addr=0x0 \
-object rng-random,id=objrng0,filename=/dev/urandom \
-device virtio-rng-pci,rng=objrng0,id=rng0,bus=pci.5,addr=0x0 \
-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \
-msg timestamp=on
char device redirected to /dev/pts/1 (label charserial0)
KVM internal error. Suberror: 1
emulation failure
EAX=00000000 EBX=00000000 ECX=000086d4 EDX=00000000
ESI=00000000 EDI=00000000 EBP=000086d4 ESP=00006d7c
EIP=00007acf EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 ffffffff 00809300
CS =f000 000f0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =0000 00000000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =0000 00000000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     000f6200 00000037
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000000
Code=b8 90 d9 00 00 66 e8 6b f7 ff ff 66 b8 0a 00 00 00 e9 61 f2 <f3> 0f 1e fb 66 57 66 56 66 53 66 53 66 89 c7 67 66 89 14 24 66 89 ce 66 e8 15 f8 ff ff 88
$ lsb_release -rd
Description:    Ubuntu Focal Fossa (development branch)
Release:        20.04

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: libvirt-daemon 6.0.0-0ubuntu5
ProcVersionSignature: Ubuntu 5.4.0-14.17-generic 5.4.18
Uname: Linux 5.4.0-14-generic x86_64
ApportVersion: 2.20.11-0ubuntu20
Architecture: amd64
Date: Sun Mar 15 14:02:54 2020
ProcEnviron:
 SHELL=/bin/bash
 LANG=en_US.UTF-8
 TERM=xterm
 PATH=(custom, no user)
SourcePackage: libvirt
UpgradeStatus: Upgraded to focal on 2020-03-15 (0 days ago)
modified.conffile..etc.libvirt.nwfilter.allow-arp.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.allow-dhcp-server.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.allow-dhcp.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.allow-incoming-ipv4.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.allow-ipv4.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.clean-traffic-gateway.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.clean-traffic.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.no-arp-ip-spoofing.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.no-arp-mac-spoofing.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.no-arp-spoofing.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.no-ip-multicast.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.no-ip-spoofing.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.no-mac-broadcast.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.no-mac-spoofing.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.no-other-l2-traffic.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.no-other-rarp-traffic.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.qemu-announce-self-rarp.xml: [modified]
modified.conffile..etc.libvirt.nwfilter.qemu-announce-self.xml: [modified]
modified.conffile..etc.libvirt.qemu.networks.default.xml: [modified]
mtime.conffile..etc.libvirt.nwfilter.allow-arp.xml: 2020-03-14T22:33:06.061183
mtime.conffile..etc.libvirt.nwfilter.allow-dhcp-server.xml: 2020-03-14T22:33:06.981181
mtime.conffile..etc.libvirt.nwfilter.allow-dhcp.xml: 2020-03-14T22:33:07.121181
mtime.conffile..etc.libvirt.nwfilter.allow-incoming-ipv4.xml: 2020-03-14T22:33:07.189181
mtime.conffile..etc.libvirt.nwfilter.allow-ipv4.xml: 2020-03-14T22:33:07.013181
mtime.conffile..etc.libvirt.nwfilter.clean-traffic-gateway.xml: 2020-03-14T22:33:06.821182
mtime.conffile..etc.libvirt.nwfilter.clean-traffic.xml: 2020-03-14T22:33:06.277182
mtime.conffile..etc.libvirt.nwfilter.no-arp-ip-spoofing.xml: 2020-03-14T22:33:06.445182
mtime.conffile..etc.libvirt.nwfilter.no-arp-mac-spoofing.xml: 2020-03-14T22:33:07.057181
mtime.conffile..etc.libvirt.nwfilter.no-arp-spoofing.xml: 2020-03-14T22:33:06.101183
mtime.conffile..etc.libvirt.nwfilter.no-ip-multicast.xml: 2020-03-14T22:33:07.157181
mtime.conffile..etc.libvirt.nwfilter.no-ip-spoofing.xml: 2020-03-14T22:33:07.089181
mtime.conffile..etc.libvirt.nwfilter.no-mac-broadcast.xml: 2020-03-14T22:33:06.233182
mtime.conffile..etc.libvirt.nwfilter.no-mac-spoofing.xml: 2020-03-14T22:33:06.945181
mtime.conffile..etc.libvirt.nwfilter.no-other-l2-traffic.xml: 2020-03-14T22:33:06.133183
mtime.conffile..etc.libvirt.nwfilter.no-other-rarp-traffic.xml: 2020-03-14T22:33:06.309182
mtime.conffile..etc.libvirt.nwfilter.qemu-announce-self-rarp.xml: 2020-03-14T22:33:06.345182
mtime.conffile..etc.libvirt.nwfilter.qemu-announce-self.xml: 2020-03-14T22:33:06.177183
mtime.conffile..etc.libvirt.qemu.networks.default.xml: 2020-03-14T22:33:05.377184