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From:   Mohammed Gamal <mgamal@redhat.com>
To:     kvm@vger.kernel.org, pbonzini@redhat.com
Cc:     sean.j.christopherson@intel.com, vkuznets@redhat.com,
        wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org,
        linux-kernel@vger.kernel.org, Mohammed Gamal <mgamal@redhat.com>
Subject: [PATCH 0/5] KVM: Support guest MAXPHYADDR < host MAXPHYADDR
Date:   Thu, 27 Feb 2020 19:23:01 +0200
Message-Id: <20200227172306.21426-1-mgamal@redhat.com>
MIME-Version: 1.0
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Sender: linux-kernel-owner@vger.kernel.org
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When EPT/NPT is enabled, KVM does not really look at guest physical=20
address size. Address bits above maximum physical memory size are reserve=
d.=20
Because KVM does not look at these guest physical addresses, it currently=
=20
effectively supports guest physical address sizes equal to the host.

This can be problem when having a mixed setup of machines with 5-level pa=
ge=20
tables and machines with 4-level page tables, as live migration can chang=
e=20
MAXPHYADDR while the guest runs, which can theoretically introduce bugs.

In this patch series we add checks on guest physical addresses in EPT=20
violation/misconfig and NPF vmexits and if needed inject the proper=20
page faults in the guest.

A more subtle issue is when the host MAXPHYADDR is larger than that of th=
e
guest. Page faults caused by reserved bits on the guest won't cause an EP=
T
violation/NPF and hence we also check guest MAXPHYADDR and add PFERR_RSVD=
_MASK
error code to the page fault if needed.


Mohammed Gamal (5):
  KVM: x86: Add function to inject guest page fault with reserved bits
    set
  KVM: VMX: Add guest physical address check in EPT violation and
    misconfig
  KVM: SVM: Add guest physical address check in NPF interception
  KVM: x86: mmu: Move translate_gpa() to mmu.c
  KVM: x86: mmu: Add guest physical address check in translate_gpa()

 arch/x86/include/asm/kvm_host.h |  6 ------
 arch/x86/kvm/mmu/mmu.c          | 10 ++++++++++
 arch/x86/kvm/mmu/paging_tmpl.h  |  2 +-
 arch/x86/kvm/svm.c              |  7 +++++++
 arch/x86/kvm/vmx/vmx.c          | 13 +++++++++++++
 arch/x86/kvm/x86.c              | 14 ++++++++++++++
 arch/x86/kvm/x86.h              |  1 +
 7 files changed, 46 insertions(+), 7 deletions(-)

--=20
2.21.1