diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 158d118..a925500 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -5779,6 +5779,23 @@ it hard or impossible to use it correctly.  The availability of
 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed.
 Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT.
 
+7.19 KVM_CAP_PPC_SECURE_GUEST
+------------------------------
+
+:Architectures: ppc
+
+This capability indicates that KVM is running on a host that has
+ultravisor firmware and thus can support a secure guest.  On such a
+system, a guest can ask the ultravisor to make it a secure guest,
+one whose memory is inaccessible to the host except for pages which
+are explicitly requested to be shared with the host.  The ultravisor
+notifies KVM when a guest requests to become a secure guest, and KVM
+has the opportunity to veto the transition.
+
+If present, this capability can be enabled for a VM, meaning that KVM
+will allow the transition to secure guest mode.  Otherwise KVM will
+veto the transition.
+
 8. Other capabilities.
 ======================
 
diff --git a/arch/powerpc/include/asm/kvm_book3s_uvmem.h b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
index 5a9834e..9cb7d8b 100644
--- a/arch/powerpc/include/asm/kvm_book3s_uvmem.h
+++ b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
@@ -5,6 +5,7 @@
 #ifdef CONFIG_PPC_UV
 int kvmppc_uvmem_init(void);
 void kvmppc_uvmem_free(void);
+bool kvmppc_uvmem_available(void);
 int kvmppc_uvmem_slot_init(struct kvm *kvm, const struct kvm_memory_slot *slot);
 void kvmppc_uvmem_slot_free(struct kvm *kvm,
 			    const struct kvm_memory_slot *slot);
@@ -30,6 +31,11 @@ static inline int kvmppc_uvmem_init(void)
 
 static inline void kvmppc_uvmem_free(void) { }
 
+static inline bool kvmppc_uvmem_available(void)
+{
+	return false;
+}
+
 static inline int
 kvmppc_uvmem_slot_init(struct kvm *kvm, const struct kvm_memory_slot *slot)
 {
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 6e8b8ff..f99b433 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -303,6 +303,7 @@ struct kvm_arch {
 	u8 radix;
 	u8 fwnmi_enabled;
 	u8 secure_guest;
+	u8 svm_enabled;
 	bool threads_indep;
 	bool nested_enable;
 	pgd_t *pgtable;
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index e716862..94f5a32 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -313,6 +313,7 @@ struct kvmppc_ops {
 			       int size);
 	int (*store_to_eaddr)(struct kvm_vcpu *vcpu, ulong *eaddr, void *ptr,
 			      int size);
+	int (*enable_svm)(struct kvm *kvm);
 	int (*svm_off)(struct kvm *kvm);
 };
 
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 85e75b1..8b8e1ed 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -5419,6 +5419,21 @@ static void unpin_vpa_reset(struct kvm *kvm, struct kvmppc_vpa *vpa)
 }
 
 /*
+ * Enable a guest to become a secure VM, or test whether
+ * that could be enabled.
+ * Called when the KVM_CAP_PPC_SECURE_GUEST capability is
+ * tested (kvm == NULL) or enabled (kvm != NULL).
+ */
+static int kvmhv_enable_svm(struct kvm *kvm)
+{
+	if (!kvmppc_uvmem_available())
+		return -EINVAL;
+	if (kvm)
+		kvm->arch.svm_enabled = 1;
+	return 0;
+}
+
+/*
  *  IOCTL handler to turn off secure mode of guest
  *
  * - Release all device pages
@@ -5538,6 +5553,7 @@ static struct kvmppc_ops kvm_ops_hv = {
 	.enable_nested = kvmhv_enable_nested,
 	.load_from_eaddr = kvmhv_load_from_eaddr,
 	.store_to_eaddr = kvmhv_store_to_eaddr,
+	.enable_svm = kvmhv_enable_svm,
 	.svm_off = kvmhv_svm_off,
 };
 
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 79b1202..da454e2 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -113,6 +113,15 @@ struct kvmppc_uvmem_page_pvt {
 	bool skip_page_out;
 };
 
+bool kvmppc_uvmem_available(void)
+{
+	/*
+	 * If kvmppc_uvmem_bitmap != NULL, then there is an ultravisor
+	 * and our data structures have been initialized successfully.
+	 */
+	return !!kvmppc_uvmem_bitmap;
+}
+
 int kvmppc_uvmem_slot_init(struct kvm *kvm, const struct kvm_memory_slot *slot)
 {
 	struct kvmppc_uvmem_slot *p;
@@ -216,6 +225,10 @@ unsigned long kvmppc_h_svm_init_start(struct kvm *kvm)
 	if (!kvm_is_radix(kvm))
 		return H_UNSUPPORTED;
 
+	/* NAK the transition to secure if not enabled */
+	if (!kvm->arch.svm_enabled)
+		return H_AUTHORITY;
+
 	srcu_idx = srcu_read_lock(&kvm->srcu);
 	slots = kvm_memslots(kvm);
 	kvm_for_each_memslot(memslot, slots) {
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index e229a81..c48862d 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -669,6 +669,12 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		     (hv_enabled && cpu_has_feature(CPU_FTR_P9_TM_HV_ASSIST));
 		break;
 #endif
+#if defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE)
+	case KVM_CAP_PPC_SECURE_GUEST:
+		r = hv_enabled && kvmppc_hv_ops->enable_svm &&
+			!kvmppc_hv_ops->enable_svm(NULL);
+		break;
+#endif
 	default:
 		r = 0;
 		break;
@@ -2167,6 +2173,14 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 		r = kvm->arch.kvm_ops->enable_nested(kvm);
 		break;
 #endif
+#if defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE)
+	case KVM_CAP_PPC_SECURE_GUEST:
+		r = -EINVAL;
+		if (!is_kvmppc_hv_enabled(kvm) || !kvm->arch.kvm_ops->enable_svm)
+			break;
+		r = kvm->arch.kvm_ops->enable_svm(kvm);
+		break;
+#endif
 	default:
 		r = -EINVAL;
 		break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 5e6234c..428c7dd 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1016,6 +1016,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_ARM_INJECT_EXT_DABT 178
 #define KVM_CAP_S390_VCPU_RESETS 179
 #define KVM_CAP_S390_PROTECTED 180
+#define KVM_CAP_PPC_SECURE_GUEST 181
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
