[RFC PATCH 0/2] KVM: nSVM: use vmcb_ctrl_area_cached instead

[Emanuele Giuseppe Esposito <eesposit@redhat.com>]

Similar to what is being done for svm save area in the nested
state (svm->nested.save), svm->nested.ctl contains some fields
that are not used. This introduces the possibility of passing
around uninitialized values, producing unnecessary bugs.

RFC: changing svm->nested.ctl however means that all functions
called with svm->nested.ctl or a normal vmcb control area
struct will need to be modified to handle the new struct. 
This is the case of vmcb_is_intercept(), which results in an
additional function definition. And this looks a little bit ugly IMO.
Therefore, the aim of this serie is to gather feedback to see
if there is a better way to change svm->nested.ctl
or if it's even worth doing it.

Based-on: <20210917120329.2013766-1-eesposit@redhat.com>
Suggested-by: Maxim Levitsky <mlevitsk@redhat.com> 
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>

Emanuele Giuseppe Esposito (2):
  nSVM: introduce struct vmcb_ctrl_area_cached
  nSVM: use vmcb_ctrl_area_cached instead of vmcb_control_area in
    svm_nested_state

 arch/x86/kvm/svm/nested.c | 74 +++++++++++++++++++++++++++++----------
 arch/x86/kvm/svm/svm.c    |  4 +--
 arch/x86/kvm/svm/svm.h    | 39 ++++++++++++++++++---
 3 files changed, 93 insertions(+), 24 deletions(-)

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2.27.0