linux-kernel - [PATCH 0/2] x86: SME: Kexec/kdump memory loading fix

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Date:   Fri, 14 Jun 2019 21:15:17 +0000
From:   "Lendacky, Thomas" <Thomas.Lendacky@....com>
To:     "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>
Subject: [PATCH 0/2] x86: SME: Kexec/kdump memory loading fix

This series addresses an issue related to kexec/kdump when SME is active.
The SME support uses a workarea located after the end of the kernel to
perform "in-place" encryption of the kernel. When kexec/kdump is used, it
is possible that some other data used by kexec/kdump could be in this area
of memory which would cause the kexec/kdump of the kernel to fail.

Create a section for SME in vmlinux.lds.S that is positioned after "_end",
so that the memory it occupies will be reclaimed after its use during
boot. Since it is part of the kernel image, there is no worry now that
kexec/kdump will place data in the SME workarea when installing the kexec/
kdump kernel. As part of this fix, clarify what occupied kernel memory is
reserved and what parts of the kernel memory are discarded.

The following patches are included:
- Identify and document what parts of the kernel image are reserved (saved)
  and what is discarded.
- Create a new SME workarea section that will be reclaimed after its use
  during boot, thus allow

This patch series is based on tip/master.

---

Tom Lendacky (2):
  x86/mm: Identify the end of the kernel area to be reserved
  x86/mm: Create an SME workarea in the kernel for early encryption

 arch/x86/include/asm/sections.h    |  2 ++
 arch/x86/kernel/setup.c            |  8 +++++++-
 arch/x86/kernel/vmlinux.lds.S      | 33 +++++++++++++++++++++++++++++-
 arch/x86/mm/mem_encrypt_identity.c | 22 ++++++++++++++++++--
 4 files changed, 61 insertions(+), 4 deletions(-)

-- 
2.17.1