[PATCH AUTOSEL 5.7 289/388] KVM: PPC: Book3S HV: Relax check on H_SVM_INIT_ABORT

Sasha Levin
2020-06-18T02:27:43Z

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 93493f0cbfe8..ee581cde4878 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