linux-kernel - [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1468351223-3250-1-git-send-email-pbonzini@redhat.com>
Date:	Tue, 12 Jul 2016 21:20:19 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [RFC PATCH 0/4] KVM: Emulate UMIP (or almost do so)

UMIP (User-Mode Instruction Prevention) is a feature of future
Intel processors (Cannonlake?) that blocks SLDT, SGDT, STR, SIDT
and SMSW from user-mode processes.

The idea here is to use virtualization intercepts to emulate UMIP; it
slows down the instructions when they're executed in ring 0, but they
are really never executed in practice.  On AMD systems it's possible
to emulate it entirely; instead on Intel systems it's *almost* possible
to emulate it, because SMSW doesn't cause a vmexit, and hence SMSW will
not fault.

This patch series provides the infrastructure and implements it on
Intel.  I tested it through kvm-unit-tests.

Still I think the idea is interesting, even if it's buggy for current
Intel processors.  Any opinions?

Paolo

Paolo Bonzini (4):
  x86: add UMIP feature and CR4 bit
  KVM: x86: emulate sldt and str
  KVM: x86: add support for emulating UMIP
  KVM: vmx: add support for emulating UMIP

 arch/x86/include/asm/cpufeatures.h          |  1 +
 arch/x86/include/asm/kvm_host.h             |  3 ++-
 arch/x86/include/asm/vmx.h                  |  1 +
 arch/x86/include/uapi/asm/processor-flags.h |  2 ++
 arch/x86/include/uapi/asm/vmx.h             |  4 +++
 arch/x86/kvm/cpuid.c                        |  5 +++-
 arch/x86/kvm/cpuid.h                        |  8 ++++++
 arch/x86/kvm/emulate.c                      | 40 ++++++++++++++++++++++++-----
 arch/x86/kvm/svm.c                          |  6 +++++
 arch/x86/kvm/vmx.c                          | 40 ++++++++++++++++++++++++++++-
 arch/x86/kvm/x86.c                          |  3 +++
 11 files changed, 104 insertions(+), 9 deletions(-)

-- 
1.8.3.1