From: Laurent Dufour <ldufour@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
kvm-ppc@vger.kernel.org
Cc: Bharata B Rao <bharata@linux.ibm.com>
Subject: [PATCH 1/2] KVM: PPC: Book3S HV: check caller of H_SVM_* Hcalls
Date: Fri, 20 Mar 2020 11:26:42 +0100 [thread overview]
Message-ID: <20200320102643.15516-2-ldufour@linux.ibm.com> (raw)
In-Reply-To: <20200320102643.15516-1-ldufour@linux.ibm.com>
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 <bharata@linux.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
---
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 33be4d93248a..43773182a737 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1074,25 +1074,35 @@ 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:
--
2.25.2
next prev parent reply other threads:[~2020-03-20 10:40 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-20 10:26 [PATCH 0/2] Fix SVM hang at startup Laurent Dufour
2020-03-20 10:26 ` Laurent Dufour [this message]
2020-03-20 12:22 ` [PATCH 1/2] KVM: PPC: Book3S HV: check caller of H_SVM_* Hcalls Greg Kurz
2020-03-20 14:43 ` Laurent Dufour
2020-03-23 23:43 ` Paul Mackerras
2020-03-24 12:00 ` Greg Kurz
2020-03-24 13:13 ` Laurent Dufour
2020-03-21 0:40 ` Ram Pai
2020-03-20 10:26 ` [PATCH 2/2] KVM: PPC: Book3S HV: H_SVM_INIT_START must call UV_RETURN Laurent Dufour
2020-03-20 11:24 ` Bharata B Rao
2020-03-20 14:36 ` Laurent Dufour
2020-03-23 4:21 ` Bharata B Rao
2020-03-21 0:47 ` Ram Pai
2020-03-23 14:09 ` Fabiano Rosas
2020-03-24 2:54 ` [PATCH 0/2] Fix SVM hang at startup Paul Mackerras
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