Re: [PATCH v2 07/20] x86: decompressor: Only call the trampoline when changing paging levels

From: Kirill A. Shutemov
Date: Mon May 15 2023 - 10:07:48 EST

On Mon, May 08, 2023 at 09:03:17AM +0200, Ard Biesheuvel wrote:
> Since we know the current and desired number of paging levels when
> preparing the trampoline, let's not call the trampoline at all when we
> know that calling it is not going to result in a change to the number of
> paging levels. Given that we are already running in long mode, the PAE
> and LA57 settings are necessarily consistent with the currently active
> page tables - the only difference is that we will always preserve
> CR4.MCE in this case, but this will be cleared by the real kernel
> startup code if CONFIG_X86_MCE is not enabled.
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>

Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>

Kiryl Shutsemau / Kirill A. Shutemov