system becomes extremely slow after disable cache

Question

I disable the cache by setting the CD bit of CR0 for my intel machine. I used the code described in my previous post

I also use the smp_call_function() function to set all CPU's CR0.

The problem is:

After I set all CPU's CR0's CD bit, the machine becomes extremely slow. I cannot even use keyboard.

My question is:

I want to check the CR0 register after I disable the cache by setting the CD bit of CR0. So I need to be able to use the keyboard at least.

Is there anyway that can help me use the keyboard after I disable cache?

It's totally out of my expectation that disabling the cache can make the system almost freeze.