Re: [PATCH 4/6] x86/mtrr: don't let mtrr_type_lookup() return MTRR_TYPE_INVALID

[Linus Torvalds]

On Mon, Feb 6, 2023 at 11:29 PM Juergen Gross <jgross@xxxxxxxx> wrote:
>
> mtrr_type_lookup() should always return a valid memory type. In case
> there is no information available, it should return the default UC.

Why isn't the second case (ie MTRR_STATE_MTRR_ENABLED not being set)
returning 'mtrr_state.def_type'. That's what the hw does, no?

> At the same time the mtrr_type_lookup() stub for the !CONFIG_MTRR
> case should set uniform to 1, as if the memory range would be
> covered by no MTRR at all.

.. but you didn't do that for the CONFIG_MTRR, so now they return
MTRR_TYPE_UNCACHABLE, but don't set uniform=1.

              Linus