Re: [PATCH] [v2] x86/doc: add PTI description

From: Hector Martin 'marcan'
Date: Thu Jan 04 2018 - 20:43:38 EST


On 2018-01-05 09:24, Dave Hansen wrote:
> + Not specifying this option nothing is equivalent to
> + pti=auto.

-nothing

> +Page Table Isolation (pti, previously known as KAISER[1]) is a
> +countermeasure against attacks on kernel address information such
> +as the "Meltdown" approach[2].

It's not really just address information, but any data. Maybe "attacks
that leak kernel memory"?

> +To avoid leaking address information, we create an new, independent

Same issue here. Also an -> a.

> +copy of the page tables which are used only when running userspace

are -> is. The copy is singular.

> +applications. When the kernel is entered via syscalls, interrupts or
> +exceptions, page tables are switched to the full "kernel" copy. When

"the page tables".

> +crippled by setting the NX bit in the top level. This ensures
> +that if a kernel->user CR3 switch is missed that userspace will
> +crash immediately upon executing its first instruction.

"that userspace" -> "then userspace"

--
Hector Martin "marcan" (marcan@xxxxxxxxx)
Public Key: https://mrcn.st/pub