KVM: x86/PVM: Provide exit reason for PVM VM entry fails

Extend pvm_get_exit_info() to provide the exit reason when PVM VM entry
fails. This change improves handling of failed VM entry scenarios, thus
increasing overall robustness and reliability of virtual machines.

Suggested-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Jinrong Liang <cloudliang@tencent.com>

Author: Jinrong Liang

arch/x86/kvm/pvm/pvm.c

@@ -2481,6 +2481,8 @@ static void pvm_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason, u64 *info1, u6
 	else if (pvm->exit_vector >= FIRST_EXTERNAL_VECTOR &&
 		 pvm->exit_vector < NR_VECTORS)
 		*reason = PVM_EXIT_REASONS_INTERRUPT;
+	else if (pvm->exit_vector == SWITCH_EXIT_REASONS_FAILED_VMETNRY)
+		*reason = PVM_FAILED_VMENTRY_VECTOR;
 	else
 		*reason = pvm->exit_vector;
 	*info1 = pvm->exit_vector;