Re: How to change page permission from inside the kernel?

On Fri, 06 Jul 2018 20:06:29 +0200, Ahmed Soliman said:

I have a memory page allocated with mmap() from user space, This address is passed to some kernel module (kvm_intel to be specific) and i want to know how can I change the page permission from inside there My goal is to achieve something like this mprotect(mem, PAGE_SIZE, PROT_READ) except for mprotect can't be called from the kernel, and I couldn't find the right way to do it.

You better have a *really* good reason for wanting to do that from inside the kernel, when userspace is perfectly able to do it for itself. So there's two questions here: 1) Why does the page's protection need to be changed? 2) And why from inside the kernel?