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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun, 6 Jun 2021 14:23:21 -0700
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Subject: Re: [GIT PULL] x86/urgent for v5.13-rc5
To:     Mike Rapoport <rppt@linux.ibm.com>
Cc:     Borislav Petkov <bp@suse.de>, x86-ml <x86@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>
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On Sun, Jun 6, 2021 at 1:58 PM Mike Rapoport <rppt@linux.ibm.com> wrote:
>
> A while ago hpa said:
>
>         As far as I know, Windows 7 actually reserves all memory below
>         1 MiB to avoid BIOS bugs.
>
> (https://bugzilla.kernel.org/show_bug.cgi?id=16661#c2)

It would be good to have that checked somehow.

I don't think this matters on any machine with gigs of RAM, but I do
wonder about the people who want to do small configurations. Maybe
they've given up on x86?

It also eats into that somewhat precious legacy DMA resource and eats
up a fair chunk of that. Again, not an issue on modern hardware, but
..

> I believe that reserving everything below 1M after the real mode trampoline
> is allocated reduces amount of hidden dependencies and makes things simpler
> overall.

Simpler, perhaps, and _I_ personally don't care about about 512kB of
memory any more on any machines I have, but ..

          Linus