[PATCH 00/12] Add support for nested SVM (kernel) v6

[Alexander Graf <agraf@suse.de>]

The current generation of virtualization extensions only supports one VM layer.
While we can't change that, it is pretty easy to emulate the CPU's behavior
and implement the virtualization opcodes ourselves.

This patchset does exactly this for SVM. Using it, KVM can run within a VM.
Since we're emulating the real CPU's behavior, this should also enable other
VMMs to run within KVM.
So far I've only tested to run KVM inside the VM though.

As always, comments and suggestions are highly welcome.

v2 takes most comments from Avi into account.

v3 addresses Joergs comments, including

- V_INTR_MASKING support
- a generic permission checking helper

v4 addresses even more comments from Joerg, including

- don't use the guest's hsave to store the guest's vmcb in
- add nested=<int> flag for kvm-amd.ko, defaults to 0 (off)
- include Joerg's VM_CR MSR patch

v5 removes the IOPM merging code

v6 addresses comments from Joerg and Anthony:

- don't flood the host's log with printks
- export SVM capability to userspace (SVM CPUID capability)
- prettify nsvm_printk
- pass an error code on inject_gp (0)
- always close interrupt_window if GIF=0
- fix 32-bit l1 guests
- warn in syslog if nested=1 on module load
- huge speed improvements

To be usable, this patchset requires simple changes in the userspace part.
For now you can easily use the patches I sent to the list when I sent the first
version if you comment out the new svm masking in qemu/target-i386/helper.c.

I will submit a newer version of the userspace patch once the kernel parts are OK.

Known issues:

- TODO: #VMEXIT on save/restore
- SMP l2 guests break with in-kernel-apic

Thanks for reviewing!

Alex

Alexander Graf (11):
  Clean up VINTR setting v6
  Move EFER and MSR constants to generic x86 code v6
  Add helper functions for nested SVM v6
  Implement GIF, clgi and stgi v6
  Implement hsave v6
  Add VMLOAD and VMSAVE handlers v6
  Add VMRUN handler v6
  Add VMEXIT handler and intercepts v6
  Allow setting the SVME bit v6
  Only allow setting of EFER_SVME when CPUID SVM is set v6
  Accelerate nested SVM by emulating parts of GIF=0 v6

Joerg Roedel (1):
  Allow read access to MSR_VM_VR v6

 arch/x86/include/asm/kvm_host.h  |    6 +
 arch/x86/include/asm/msr-index.h |    7 +
 arch/x86/kvm/kvm_svm.h           |   10 +
 arch/x86/kvm/svm.c               |  763 +++++++++++++++++++++++++++++++++++++-
 arch/x86/kvm/svm.h               |    4 -
 arch/x86/kvm/x86.c               |   60 +++-
 6 files changed, 811 insertions(+), 39 deletions(-)