Help with record/replay

[Alex Bennée]

Hi Pavel,

I'm trying to get reverse debugging working to look at a Xen problem and
I'm confused about what is going wrong. I've converted by normal setup
which uses a ZFS block device to qcow2 so I have a place for the
snapshots:

  ./qemu-system-aarch64 -machine virt,virtualization=on -cpu cortex-a57 \
    -serial mon:stdio -netdev user,id=net1,hostfwd=tcp::2222-:22 \
    -device virtio-net-pci,netdev=net1 \
    -device virtio-scsi-pci \
    -drive file=debian-buster-arm64.qcow2,id=hd0,index=0,if=none,snapshot=on \
    -device scsi-hd,drive=hd0 \
    -display none -m 8192 \
    -kernel ~/lsrc/xen/xen.build.arm64-xen/xen/xen \
    -append "dom0_mem=2G,max:2G dom0_max_vcpus=4" \
    -device 
guest-loader,addr=0x47000000,kernel=$HOME/lsrc/linux.git/builds/arm64/arch/arm64/boot/Image,bootargs="root=/dev/sda2
  console=hvc0 earlyprintk=xen" \
    -icount shift=5,rr=record,rrfile=xencrash.bin,rrsnapshot=init \
    -object filter-replay,id=replay,netdev=net1

but when I try to replay I get:

  qemu-system-aarch64: Snapshot 'init' does not exist in one or more devices
  qemu-system-aarch64: Could not load snapshot for icount replay

So do I need another qcow device just for snapshots?

-- 
Alex Bennée