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From:   Michael Kelley <mikelley@microsoft.com>
To:     James Morris <jmorris@namei.org>, Sasha Levin <sashal@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Borislav Petkov <bp@alien8.de>
CC:     x86-ml <x86@kernel.org>, lkml <linux-kernel@vger.kernel.org>,
        James Morris <James.Morris@microsoft.com>
Subject: RE: [GIT PULL] x86/urgent for v5.13-rc5
Thread-Topic: [GIT PULL] x86/urgent for v5.13-rc5
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From: James Morris <jmorris@namei.org> Sent: Monday, June 7, 2021 11:47 AM
>=20
> On Sun, 6 Jun 2021, Sasha Levin wrote:
>=20
> > >
> > >Let's see if Sasha can dig out something... CCed.
> > >
> > >@Sasha, can you figure out who we can talk to whether Windoze reserves
> > >the first megabyte of memory unconditionally?
> >
> > That's a great question, but I can't help there anymore :)
> >
> > Adding James Morris...
>=20
> Adding Michael Kelley.
>=20

I checked with the Windows team.  Peter Anvin's statement from 11
years ago is true.  On Intel and AMD processors, Windows unconditionally
reserves the 1st megabyte of memory, minus one page used for real
mode startup.   This is done to work around BIOS bugs.

Michael