Harden kvm_vcpu_map() usage against memory leaks by yelling if there's already
a valid mapping, and then unmapping the existing mapping before establishing a
new one.  To get there, add a CLASS() for local, on-stack usage, to guarantee
the map metadata is zero-initialized (well, so long as the CLASS() is used).

Prompted by 2f2312c422fd ("KVM: nVMX: Put vmcs12 pages if nested VM-Enter fails
due to invalid guest state").

Patch 1 is related in that it's needed to avoid tripping the new WARN.

The PPC change is compile-tested only.

Sean Christopherson (6):
  KVM: nVMX: Ensure KVM_REQ_GET_NESTED_STATE_PAGES is cleared on VM-Exit
  KVM: nSVM: Add CLASS()es for automagically handling local
    kvm_vcpu_map() usage
  KVM: nSVM: Use CLASS(kvm_vcpu_map_local) for SMM VMCB mappings
  KVM: nVMX: Use CLASS(kvm_vcpu_map_local_readonly) for MSR bitmap
    merging
  KVM: PPC: Use CLASS(kvm_vcpu_map_local_readonly) for patching dcbz
  KVM: Harden kvm_vcpu_map() against double-mapping and thus leaking
    references

 arch/powerpc/kvm/book3s_pr.c |  9 +++----
 arch/x86/kvm/svm/nested.c    | 18 ++++++--------
 arch/x86/kvm/svm/svm.c       | 46 +++++++++++++-----------------------
 arch/x86/kvm/vmx/nested.c    | 13 +++++-----
 include/linux/kvm_host.h     | 19 +++++++++++++++
 virt/kvm/kvm_main.c          |  3 +++
 6 files changed, 55 insertions(+), 53 deletions(-)


base-commit: 6bc96b971766fbbbbdd9fb2642cedacaf02da957
-- 
2.55.0.229.g6434b31f56-goog