Kernel panic when running qemu/vfio-user-v0.9 with -cpu host option

[karlatec]

Guest OS freezes or kernel panics when Qemu is run with -cpu host option.

qemu built with:

vfio-user-v0.9

commit 29e3142d6c23adb327c9752a4dd988b24c33d24b (HEAD -> vfio-user-v0.9, origin/vfio-user-v0.9)
Author: John Johnson <john.g.johnson@oracle.com>
Date:   Sun Jun 6 22:51:22 2021 -0700

    remove MAPPABLE flag
    change max_msg to max_xfer
    threading is hard - fix discon race


./configure --target-list="x86_64-softmmu" --enable-kvm --enable-linux-aio --enable-numa && make -j100

Qemu command line:

taskset -a -c 1-2 /home/klateck/work/qemu-vfiouser/build/qemu-system-x86_64 \
-m 1024 \
--enable-kvm \
-cpu host \
-smp 2 \
-vga std \
-vnc :100 -daemonize \
-object memory-backend-file,id=mem,size=1024M,mem-path=/dev/hugepages,share=on,prealloc=yes,host-nodes=0,policy=bind \
-snapshot -monitor telnet:127.0.0.1:10002,server,nowait \
-numa node,memdev=mem \
-pidfile /home/klateck/vhost_test/vms/0/qemu.pid \
-serial file:/home/klateck/vhost_test/vms/0/serial.log \
-D /home/klateck/vhost_test/vms/0/qemu.log \
-chardev file,path=/home/klateck/vhost_test/vms/0/seabios.log,id=seabios \
-device isa-debugcon,iobase=0x402,chardev=seabios \
-net user,hostfwd=tcp::10000-:22,hostfwd=tcp::10001-:8765 \
-net nic \
-drive file=/home/sys_sgci/spdk_dependencies/spdk_test_image.qcow2,if=none,id=os_disk \
-device ide-hd,drive=os_disk,bootindex=0

This results in either a guest OS kernel panic:
kp1.txt
kp2.txt

Or a freeze when booting guest OS:
freeze1.txt
which seems to produce a dmesg error on host at the same time:

[1960842.564891] kvm [4075811]: vcpu0, guest rIP: 0xffffffffaf06b064 disabled perfctr wrmsr: 0xc0010007 data 0xffff

Host OS info:
Fedora 32 5.8.15-201.fc32.x86_64
gcc version 10.2.1 20201125 (Red Hat 10.2.1-9) (GCC)

Guest OS info:
Fedora 32 vhost32-cloud-12806 5.6.6-300.fc32.x86_64

[karlatec]

Same issue on qemu/vfio-user-v0.91 branch