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    Subject[PATCH 5.7 284/477] KVM: PPC: Book3S HV: Relax check on H_SVM_INIT_ABORT
    Date
    From: Laurent Dufour <ldufour@linux.ibm.com>

    [ Upstream commit e3326ae3d59e443a379367c6936941d6ab55d316 ]

    The commit 8c47b6ff29e3 ("KVM: PPC: Book3S HV: Check caller of H_SVM_*
    Hcalls") added checks of secure bit of SRR1 to filter out the Hcall
    reserved to the Ultravisor.

    However, the Hcall H_SVM_INIT_ABORT is made by the Ultravisor passing the
    context of the VM calling UV_ESM. This allows the Hypervisor to return to
    the guest without going through the Ultravisor. Thus the Secure bit of SRR1
    is not set in that particular case.

    In the case a regular VM is calling H_SVM_INIT_ABORT, this hcall will be
    filtered out in kvmppc_h_svm_init_abort() because kvm->arch.secure_guest is
    not set in that case.

    Fixes: 8c47b6ff29e3 ("KVM: PPC: Book3S HV: Check caller of H_SVM_* Hcalls")
    Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
    Reviewed-by: Greg Kurz <groug@kaod.org>
    Reviewed-by: Ram Pai <linuxram@us.ibm.com>
    Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/powerpc/kvm/book3s_hv.c | 11 ++++++++---
    1 file changed, 8 insertions(+), 3 deletions(-)

    diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
    index 93493f0cbfe8e..ee581cde48788 100644
    --- a/arch/powerpc/kvm/book3s_hv.c
    +++ b/arch/powerpc/kvm/book3s_hv.c
    @@ -1099,9 +1099,14 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
    ret = kvmppc_h_svm_init_done(vcpu->kvm);
    break;
    case H_SVM_INIT_ABORT:
    - ret = H_UNSUPPORTED;
    - if (kvmppc_get_srr1(vcpu) & MSR_S)
    - ret = kvmppc_h_svm_init_abort(vcpu->kvm);
    + /*
    + * Even if that call is made by the Ultravisor, the SSR1 value
    + * is the guest context one, with the secure bit clear as it has
    + * not yet been secured. So we can't check it here.
    + * Instead the kvm->arch.secure_guest flag is checked inside
    + * kvmppc_h_svm_init_abort().
    + */
    + ret = kvmppc_h_svm_init_abort(vcpu->kvm);
    break;

    default:
    --
    2.25.1


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