KVM: arm64: Introduce and use predicates that check for protected VMs

In order to determine whether or not a VM or vcpu are protected,
introduce helpers to query this state. While at it, use the vcpu
helper to check vcpus protected state instead of the kvm one.

Co-authored-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-19-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Fuad Tabba

arch/arm64/include/asm/kvm_host.h

@@ -211,6 +211,7 @@ typedef unsigned int pkvm_handle_t;
 struct kvm_protected_vm {
 	pkvm_handle_t handle;
 	struct kvm_hyp_memcache teardown_mc;
+	bool enabled;
 };
 
 struct kvm_mpidr_data {
@@ -1295,10 +1296,9 @@ struct kvm *kvm_arch_alloc_vm(void);
 
 #define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
 
-static inline bool kvm_vm_is_protected(struct kvm *kvm)
-{
-	return false;
-}
+#define kvm_vm_is_protected(kvm)	(is_protected_kvm_enabled() && (kvm)->arch.pkvm.enabled)
+
+#define vcpu_is_protected(vcpu)		kvm_vm_is_protected((vcpu)->kvm)
 
 int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature);
 bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu);

arch/arm64/kvm/hyp/include/nvhe/pkvm.h

@@ -53,6 +53,11 @@ pkvm_hyp_vcpu_to_hyp_vm(struct pkvm_hyp_vcpu *hyp_vcpu)
 	return container_of(hyp_vcpu->vcpu.kvm, struct pkvm_hyp_vm, kvm);
 }
 
+static inline bool pkvm_hyp_vcpu_is_protected(struct pkvm_hyp_vcpu *hyp_vcpu)
+{
+	return vcpu_is_protected(&hyp_vcpu->vcpu);
+}
+
 void pkvm_hyp_vm_table_init(void *tbl);
 void pkvm_host_fpsimd_state_init(void);
 

arch/arm64/kvm/hyp/nvhe/switch.c

@@ -209,7 +209,7 @@ static const exit_handler_fn pvm_exit_handlers[] = {
 
 static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu)
 {
-	if (unlikely(kvm_vm_is_protected(kern_hyp_va(vcpu->kvm))))
+	if (unlikely(vcpu_is_protected(vcpu)))
 		return pvm_exit_handlers;
 
 	return hyp_exit_handlers;
@@ -228,9 +228,7 @@ static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu)
  */
 static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code)
 {
-	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
-
-	if (kvm_vm_is_protected(kvm) && vcpu_mode_is_32bit(vcpu)) {
+	if (unlikely(vcpu_is_protected(vcpu) && vcpu_mode_is_32bit(vcpu))) {
 		/*
 		 * As we have caught the guest red-handed, decide that it isn't
 		 * fit for purpose anymore by making the vcpu invalid. The VMM