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    Subject[PATCH v2 1/6] KVM: SVM: restore the L1 host state prior to resuming nested guest on SMM exit
    Date
    Otherwise guest entry code might see incorrect L1 state (e.g paging state).

    Fixes: 37be407b2ce8 ("KVM: nSVM: Fix L1 state corruption upon return from SMM")

    Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
    ---
    arch/x86/kvm/svm/svm.c | 23 +++++++++++++----------
    1 file changed, 13 insertions(+), 10 deletions(-)

    diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
    index 1a70e11f0487..4aa269a587d0 100644
    --- a/arch/x86/kvm/svm/svm.c
    +++ b/arch/x86/kvm/svm/svm.c
    @@ -4347,27 +4347,30 @@ static int svm_leave_smm(struct kvm_vcpu *vcpu, const char *smstate)
    gpa_to_gfn(vmcb12_gpa), &map) == -EINVAL)
    return 1;

    - if (svm_allocate_nested(svm))
    + if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr),
    + &map_save) == -EINVAL)
    return 1;

    - vmcb12 = map.hva;
    -
    - nested_load_control_from_vmcb12(svm, &vmcb12->control);
    -
    - ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12);
    - kvm_vcpu_unmap(vcpu, &map, true);
    + if (svm_allocate_nested(svm))
    + return 1;

    /*
    * Restore L1 host state from L1 HSAVE area as VMCB01 was
    * used during SMM (see svm_enter_smm())
    */
    - if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr),
    - &map_save) == -EINVAL)
    - return 1;

    svm_copy_vmrun_state(&svm->vmcb01.ptr->save,
    map_save.hva + 0x400);

    + /*
    + * Restore L2 state
    + * */
    +
    + vmcb12 = map.hva;
    + nested_load_control_from_vmcb12(svm, &vmcb12->control);
    + ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12);
    +
    + kvm_vcpu_unmap(vcpu, &map, true);
    kvm_vcpu_unmap(vcpu, &map_save, true);
    }
    }
    --
    2.26.3
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