linux-kernel - [RFC PATCH 0/2] KVM: nSVM: use vmcb_ctrl_area

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Message-Id: <20210917124956.2042052-1-eesposit@redhat.com>
Date:   Fri, 17 Sep 2021 08:49:54 -0400
From:   Emanuele Giuseppe Esposito <eesposit@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
        linux-kernel@...r.kernel.org,
        Emanuele Giuseppe Esposito <eesposit@...hat.com>
Subject: [RFC PATCH 0/2] KVM: nSVM: use vmcb_ctrl_area_cached instead

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@...hat.com>
Suggested-by: Maxim Levitsky <mlevitsk@...hat.com> 
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@...hat.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(-)

-- 
2.27.0