I found that things were unstable unless the following were also added -cpu Nehalem,-rdtscp (the CPU can be higher than Nehalem but obviously your host CPU actually has to be equal or greater too)
-rdtscp is a known issue that has since been workedaround (see bug #1894836 ). -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1872644 Title: MacOS host qemu-system-x86_64 -cpu host not working Status in QEMU: New Bug description: MacOS: 10.15.4 uname -a: Linux door 4.15.0-96-generic #97-Ubuntu SMP Wed Apr 1 03:25:46 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux I am using qemu on mac host, with ubuntu client. I used to have "-cpu host" in my qemu command as follow:- qemu-system-x86_64 \ -no-user-config \ -nodefaults \ -name u64d01 \ -show-cursor \ -M q35,accel=hvf,usb=off,vmport=off \ -cpu host \ -m 8192M \ -smp 4 \ -rtc base=utc,clock=host \ -device virtio-blk-pci,drive=ssd1 \ -drive id=ssd1,file=/Users/js/code/vm/qemu/u64d01.qcow2,if=none,format=qcow2 \ -device virtio-net-pci,netdev=nic1,mac=52:54:98:76:54:33 \ -netdev user,id=nic1,ipv4=on,ipv6=on,hostname=u64d01,hostfwd=tcp::2222-:22 \ -device virtio-tablet-pci \ -device virtio-vga \ -device ich9-intel-hda,id=snd,msi=on \ -device hda-output,id=snd-codec0,bus=snd.0,cad=0,audiodev=snd0 \ -audiodev coreaudio,id=snd0 Base on log of one of the vm, it was definitely working on 2020-01-17(base on journal inside vm), with qemu 4.2.0, which I installed with brew. The only way to make it work is to remove "-cpu host". Already tried with 4.1.1, 4.2 and 5.0rc2. Same result. To reproduce, try above with a Ubuntu 18.04 installation cd. Client will crash during kernel loading. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1872644/+subscriptions
