*Here's the commit that causes the problem:*
$ git checkout d185c094b404b4ff392b77d1244c0233da7d53bd
qemu-char: eliminate busy waiting on can_read returning zero
*Symptoms:*
When the VM boots everything crawls and the host CPU is at 100%,
messages are printing extremely slowly on the VM console
and the VM is not making any boot progress......... printing kernel
messages once a second or so.......
Something in QEMU appears to be spinning.
Here's my command line:
qemu-system-x86_64 -enable-kvm -m 2048 -smp
2,sockets=1,cores=1,threads=1 -nodefconfig -rtc base=utc -no-shutdown
disk.img -serial pty -monitor unix:/tmp/devguest,server,nowait -netdev
type=tap,vhost=on,id=hostnet0,script=kvmifup.sh,downscript=kvmifdown.sh
-device virtio-net-pci,netdev=hostnet0,mac=12:34:36:00:00:02 -usb
-device usb-tablet,id=input0 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5
- Michael Hines
