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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc:     Sean Christopherson <seanjc@google.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Maxim Levitsky <mlevitsk@redhat.com>,
        Cathy Avery <cavery@redhat.com>,
        Emanuele Giuseppe Esposito <eesposit@redhat.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Michael Roth <mdroth@linux.vnet.ibm.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH 0/6] KVM: nSVM: Fix issues when SMM is entered from L2
Date:   Mon, 28 Jun 2021 12:44:19 +0200
Message-Id: <20210628104425.391276-1-vkuznets@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

This is a continuation of "[PATCH RFC] KVM: nSVM: Fix L1 state corruption
upon return from SMM". 

VMCB split commit 4995a3685f1b ("KVM: SVM: Use a separate vmcb for the
nested L2 guest") broke return from SMM when we entered there from guest
(L2) mode. Gen2 WS2016/Hyper-V is known to do this on boot. The problem
appears to be that VMCB01 gets irreversibly destroyed during SMM execution.
Previously, we used to have 'hsave' VMCB where regular (pre-SMM) L1's state
was saved upon nested_svm_vmexit() but now we just switch to VMCB01 from
VMCB02.

While writing a selftest for the issue, I've noticed that 'svm->nested.ctl'
doesn't get restored after KVM_GET_NESTED_STATE/KVM_SET_NESTED_STATE cycle
when guest happens to be in SMM triggered from L2. "KVM: nSVM: Restore
nested control upon leaving SMM" is aimed to fix that.

First two patches of the series add missing sanity checks for 
MSR_VM_HSAVE_PA which has to be page aligned and not zero.

Vitaly Kuznetsov (6):
  KVM: nSVM: Check the value written to MSR_VM_HSAVE_PA
  KVM: nSVM: Check that VM_HSAVE_PA MSR was set before VMRUN
  KVM: nSVM: Introduce svm_copy_nonvmloadsave_state()
  KVM: nSVM: Fix L1 state corruption upon return from SMM
  KVM: nSVM: Restore nested control upon leaving SMM
  KVM: selftests: smm_test: Test SMM enter from L2

 arch/x86/kvm/svm/nested.c                     | 45 +++++++-----
 arch/x86/kvm/svm/svm.c                        | 51 +++++++++++++-
 arch/x86/kvm/svm/svm.h                        |  4 ++
 tools/testing/selftests/kvm/x86_64/smm_test.c | 70 +++++++++++++++++--
 4 files changed, 144 insertions(+), 26 deletions(-)

-- 
2.31.1