If you're not running a Zen 2 CPU or APU, you don't have to worry about this.
If you're running the latest kernel, which automatically sets the chicken bit, you don't have to worry about this.
If you're running fixed microcode, which is only available for Rome, Castle Peak and Mendocino, you don't have to worry about this. Good microcode revisions are:
Rome / Castle Peak: 0x0830107a (published)
Xbox Series X: unknown
Renoir / Grey Hawk: 0x0860010b
Lucienne: 0x08608105
Matisse: 0x08701032
Van Gogh (Steam Deck): unknown
Mendocino: 0x08a00008 (published)
If you're running neither the latest kernel, nor fixed microcode, you should set the chicken bit yourself until you have updated those.
wrmsr -a 0xc0011029 $(($(rdmsr -c 0xc0011029) | (1<<9)))
Comments
If you're not running a Zen 2 CPU or APU, you don't have to worry about this.
If you're running the latest kernel, which automatically sets the chicken bit, you don't have to worry about this.
If you're running fixed microcode, which is only available for Rome, Castle Peak and Mendocino, you don't have to worry about this. Good microcode revisions are:
If you're running neither the latest kernel, nor fixed microcode, you should set the chicken bit yourself until you have updated those.