Re: [PATCH] x86_64: disable identity mappings statically

[Eric W. Biederman]

Jiri Olsa <jolsa@xxxxxxxxxx> writes:

> hi,
>
> while browsing the page table setup code, I noticed the x86_64 head
> code might not need the identity mappings at all.
> It seems it's ok to switch it off completely from the begining,
> unless I'm missing something.

Have you tested it?

I expect you will find that we need the identity mapping because
before we load this page table we are running with virt==phys
and we need the identity mapping retained  in the new page table
so we can get to the instruction after movq %rax, %cr0.

Eric
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