From 8c47b6ff29e3d88484fe59d02f9db6de7e44e310 Mon Sep 17 00:00:00 2001 From: Laurent Dufour Date: Fri, 20 Mar 2020 11:26:42 +0100 Subject: [PATCH] KVM: PPC: Book3S HV: Check caller of H_SVM_* Hcalls The Hcall named H_SVM_* are reserved to the Ultravisor. However, nothing prevent a malicious VM or SVM to call them. This could lead to weird result and should be filtered out. Checking the Secure bit of the calling MSR ensure that the call is coming from either the Ultravisor or a SVM. But any system call made from a SVM are going through the Ultravisor, and the Ultravisor should filter out these malicious call. This way, only the Ultravisor is able to make such a Hcall. Cc: Bharata B Rao Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Signed-off-by: Laurent Dufour Reviewed-by: Ram Pai Signed-off-by: Paul Mackerras --- arch/powerpc/kvm/book3s_hv.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 85e75b12e513..a308de610cdf 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1073,25 +1073,35 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) kvmppc_get_gpr(vcpu, 6)); break; case H_SVM_PAGE_IN: - ret = kvmppc_h_svm_page_in(vcpu->kvm, - kvmppc_get_gpr(vcpu, 4), - kvmppc_get_gpr(vcpu, 5), - kvmppc_get_gpr(vcpu, 6)); + ret = H_UNSUPPORTED; + if (kvmppc_get_srr1(vcpu) & MSR_S) + ret = kvmppc_h_svm_page_in(vcpu->kvm, + kvmppc_get_gpr(vcpu, 4), + kvmppc_get_gpr(vcpu, 5), + kvmppc_get_gpr(vcpu, 6)); break; case H_SVM_PAGE_OUT: - ret = kvmppc_h_svm_page_out(vcpu->kvm, - kvmppc_get_gpr(vcpu, 4), - kvmppc_get_gpr(vcpu, 5), - kvmppc_get_gpr(vcpu, 6)); + ret = H_UNSUPPORTED; + if (kvmppc_get_srr1(vcpu) & MSR_S) + ret = kvmppc_h_svm_page_out(vcpu->kvm, + kvmppc_get_gpr(vcpu, 4), + kvmppc_get_gpr(vcpu, 5), + kvmppc_get_gpr(vcpu, 6)); break; case H_SVM_INIT_START: - ret = kvmppc_h_svm_init_start(vcpu->kvm); + ret = H_UNSUPPORTED; + if (kvmppc_get_srr1(vcpu) & MSR_S) + ret = kvmppc_h_svm_init_start(vcpu->kvm); break; case H_SVM_INIT_DONE: - ret = kvmppc_h_svm_init_done(vcpu->kvm); + ret = H_UNSUPPORTED; + if (kvmppc_get_srr1(vcpu) & MSR_S) + ret = kvmppc_h_svm_init_done(vcpu->kvm); break; case H_SVM_INIT_ABORT: - ret = kvmppc_h_svm_init_abort(vcpu->kvm); + ret = H_UNSUPPORTED; + if (kvmppc_get_srr1(vcpu) & MSR_S) + ret = kvmppc_h_svm_init_abort(vcpu->kvm); break; default: