linux-kernel - Re: [PATCH] x86/mm: Create an SME workarea in the kernel for early encryption

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Message-ID: <053ded24-eb70-0e88-5e0c-312ea93a6fd0@intel.com>
Date:   Wed, 12 Jun 2019 08:00:37 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     "Lendacky, Thomas" <Thomas.Lendacky@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Baoquan He <bhe@...hat.com>, Lianbo Jiang <lijiang@...hat.com>
Subject: Re: [PATCH] x86/mm: Create an SME workarea in the kernel for early
 encryption

On 6/12/19 6:32 AM, Lendacky, Thomas wrote:
> Create a section for SME in the vmlinux.lds.S.  Position it after "_end"
> so that the memory will be reclaimed during boot and, since it is all
> zeroes, it compresses well. 

I don't think I realized that things after _end get reclaimed.  Do we do
that at the same spot that we do init data or somewhere else?

How much does compressing 8MB of zeros slow down my kernel compile? ;)