[PATCH v3 08/18] KVM: arm64: Add {get,put}_pkvm_hyp_vm() helpers

[Quentin Perret <qperret@google.com>]

In preparation for accessing pkvm_hyp_vm structures at EL2 in a context
where we can't always expect a vCPU to be loaded (e.g. MMU notifiers),
introduce get/put helpers to get temporary references to hyp VMs from
any context.

Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/kvm/hyp/include/nvhe/pkvm.h |  3 +++
 arch/arm64/kvm/hyp/nvhe/pkvm.c         | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
index 24a9a8330d19..f361d8b91930 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
@@ -70,4 +70,7 @@ struct pkvm_hyp_vcpu *pkvm_load_hyp_vcpu(pkvm_handle_t handle,
 					 unsigned int vcpu_idx);
 void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu);
 
+struct pkvm_hyp_vm *get_pkvm_hyp_vm(pkvm_handle_t handle);
+void put_pkvm_hyp_vm(struct pkvm_hyp_vm *hyp_vm);
+
 #endif /* __ARM64_KVM_NVHE_PKVM_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 071993c16de8..d46a02e24e4a 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -327,6 +327,26 @@ void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 	hyp_spin_unlock(&vm_table_lock);
 }
 
+struct pkvm_hyp_vm *get_pkvm_hyp_vm(pkvm_handle_t handle)
+{
+	struct pkvm_hyp_vm *hyp_vm;
+
+	hyp_spin_lock(&vm_table_lock);
+	hyp_vm = get_vm_by_handle(handle);
+	if (hyp_vm)
+		hyp_page_ref_inc(hyp_virt_to_page(hyp_vm));
+	hyp_spin_unlock(&vm_table_lock);
+
+	return hyp_vm;
+}
+
+void put_pkvm_hyp_vm(struct pkvm_hyp_vm *hyp_vm)
+{
+	hyp_spin_lock(&vm_table_lock);
+	hyp_page_ref_dec(hyp_virt_to_page(hyp_vm));
+	hyp_spin_unlock(&vm_table_lock);
+}
+
 static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struct kvm *host_kvm)
 {
 	struct kvm *kvm = &hyp_vm->kvm;
-- 
2.47.1.613.gc27f4b7a9f-goog