Re: [PATCH 08/30] x86, kaiser: unmap kernel from userspace page tables (core patch)

From: Dave Hansen
Date: Wed Nov 22 2017 - 17:54:38 EST

On 11/20/2017 09:21 AM, Thomas Gleixner wrote:
>> +page tables are switched to the full "kernel" copy. When the
>> +system switches back to user mode, the user/shadow copy is used.
>> +
>> +The minimalistic kernel portion of the user page tables try to
>> +map only what is needed to enter/exit the kernel such as the
>> +entry/exit functions themselves and the interrupt descriptor
>> +table (IDT).
> s/try to//

Actually, they do _aspire_ "to map only what is needed". But, there
*is* some non-necessary cruft (like the first C function in an
interrupt). So, removing this language actually makes the description
less precise.