[PATCH v2 0/5] Fix EFER.NX=0 with EPT

[Avi Kivity <avi@redhat.com>]

Currently we run with EFER.NX=1 on the guest even if the guest value is 0.
This is fine with shadow, since we check bit 63 when instantiating a page
table, and fault if bit 63 is set while EFER.NX is clear.

This doesn't work with EPT, since we no longer get the change to check guest
ptes.  So we need to run with EFER.NX=0.

This is complicated by the fact that if we switch EFER.NX on the host, we'll
trap immediately, since some host pages are mapped with the NX bit set.  As
a result, we need to switch the MSR atomically during guest entry and exit.

This patchset implements the complications described above.

v2:
    Fix transition from long mode to legacy mode

Avi Kivity (5):
  KVM: Let vcpu structure alignment be determined at runtime
  KVM: VMX: Add definition for msr autoload entry
  KVM: VMX: Add definitions for guest and host EFER autoswitch vmcs
    entries
  KVM: VMX: Add facility to atomically switch MSRs on guest entry/exit
  KVM: VMX: Atomically switch efer if EPT && !EFER.NX

 arch/ia64/kvm/vmm.c        |    2 +-
 arch/powerpc/kvm/44x.c     |    2 +-
 arch/powerpc/kvm/book3s.c  |    3 +-
 arch/powerpc/kvm/e500.c    |    2 +-
 arch/s390/kvm/kvm-s390.c   |    2 +-
 arch/x86/include/asm/vmx.h |   12 +++++++-
 arch/x86/kvm/svm.c         |    2 +-
 arch/x86/kvm/vmx.c         |   64 +++++++++++++++++++++++++++++++++++++++++++-
 include/linux/kvm_host.h   |    2 +-
 virt/kvm/kvm_main.c        |    7 +++--
 10 files changed, 86 insertions(+), 12 deletions(-)