KVM: nVMX: nSVM: 'nested_run' should count guest-entry attempts that make it to guest code

Currently, the 'nested_run' statistic counts all guest-entry attempts,
including those that fail during vmentry checks on Intel and during
consistency checks on AMD. Convert this statistic to count only those
guest-entries that make it past these state checks and make it to guest
code. This will tell us the number of guest-entries that actually executed
or tried to execute guest code.
Signed-off-by: Krish Sadhukhan <Krish.Sadhukhan@oracle.com>
Message-Id: <20210609180340.104248-2-krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/nested.c

@@ -596,8 +596,6 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
 	struct kvm_host_map map;
 	u64 vmcb12_gpa;
 
-	++vcpu->stat.nested_run;
-
 	if (is_smm(vcpu)) {
 		kvm_queue_exception(vcpu, UD_VECTOR);
 		return 1;

arch/x86/kvm/svm/svm.c

@@ -3844,6 +3844,12 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
 	svm->next_rip = 0;
 	if (is_guest_mode(vcpu)) {
 		nested_sync_control_from_vmcb02(svm);
+
+		/* Track VMRUNs that have made past consistency checking */
+		if (svm->nested.nested_run_pending &&
+		    svm->vmcb->control.exit_code != SVM_EXIT_ERR)
+                        ++vcpu->stat.nested_run;
+
 		svm->nested.nested_run_pending = 0;
 	}
 

arch/x86/kvm/vmx/nested.c

@@ -3470,8 +3470,6 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 	u32 interrupt_shadow = vmx_get_interrupt_shadow(vcpu);
 	enum nested_evmptrld_status evmptrld_status;
 
-	++vcpu->stat.nested_run;
-
 	if (!nested_vmx_check_permission(vcpu))
 		return 1;
 

arch/x86/kvm/vmx/vmx.c

@@ -6809,7 +6809,18 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
 	kvm_load_host_xsave_state(vcpu);
 
+	if (is_guest_mode(vcpu)) {
+		/*
+		 * Track VMLAUNCH/VMRESUME that have made past guest state
+		 * checking.
+		 */
+		if (vmx->nested.nested_run_pending &&
+		    !vmx->exit_reason.failed_vmentry)
+			++vcpu->stat.nested_run;
+
 		vmx->nested.nested_run_pending = 0;
+	}
+
 	vmx->idt_vectoring_info = 0;
 
 	if (unlikely(vmx->fail)) {