https://lock.cmpxchg8b.com/zenbleed.html
Unfortunately trying to set the the chicken bit as described in the second link fails:
# wrmsr -a 0xc0011029 $(($(/usr/sbin/rdmsr -c 0xc0011029) | (1<<9)))
rdmsr: open: No such file or directory
bash: | (1<<9): syntax error: operand expected (error token is "| (1<<9)")