KVM: Make the instruction emulator aware of Nested Virtualization

Hi Avi, Hi Marcelo,

here is a patch-set to make the instruction emulator aware of nested
virtualization. It basically works by introducing a new callback into
the x86_ops to check if a decoded instruction must be intercepted. If it
is intercepted the instruction emulator returns straight into the guest.

I am not entirely happy with this solution because it partially
duplicates the code in the x86_emulate_insn function. But there are so
many SVM specific cases that need to be taken care of that I consider
this solution the better one (even when looking at the diff-stat).
Keeping this (SVM-specific) complexity in the SVM specific code is
better than extending the generic instruction emulator code path.

The last patch removes the ugly hacks which were required without this
patch-set to correctly handle the selective-cr0-write intercept.

I appreciate your feedback.

Thanks,

	Joerg

Diffstat:

 arch/x86/include/asm/kvm_emulate.h |    2 +
 arch/x86/include/asm/kvm_host.h    |    3 +
 arch/x86/kvm/svm.c                 |  330 ++++++++++++++++++++++++++++++------
 arch/x86/kvm/vmx.c                 |    8 +
 arch/x86/kvm/x86.c                 |    5 +
 5 files changed, 297 insertions(+), 51 deletions(-)

Shortlog:

Joerg Roedel (9):
      KVM: Add infrastructure to emulate instruction intercepts
      KVM: SVM: Add checks for CRx read and write intercepts
      KVM: SVM: Add checks for DRx read and write intercepts
      KVM: SVM: Add intercept checks for descriptor table accesses
      KVM: SVM: Add checks for all group 7 instructions
      KVM: SVM: Add intercept checks for remaining twobyte instructions
      KVM: SVM: Add intercept checks for one-byte instructions
      KVM: SVM: Add checks for IO instructions
      KVM: SVM: Remove nested sel_cr0_write handling code