KVM: add machine check counter to kvm_stat

This counter can be used for administration, debug or test purposes.
Suggested-by: NVladislav Mironov <mironov@de.ibm.com>
Signed-off-by: NQingFeng Hao <haoqf@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

arch/s390/include/asm/kvm_host.h

@@ -320,6 +320,7 @@ struct kvm_vcpu_stat {
 	u64 deliver_restart_signal;
 	u64 deliver_program_int;
 	u64 deliver_io_int;
+	u64 deliver_machine_check;
 	u64 exit_wait_state;
 	u64 instruction_epsw;
 	u64 instruction_gs;

arch/s390/kvm/interrupt.c

@@ -595,6 +595,7 @@ static int __must_check __deliver_machine_check(struct kvm_vcpu *vcpu)
 		trace_kvm_s390_deliver_interrupt(vcpu->vcpu_id,
 						 KVM_S390_MCHK,
 						 mchk.cr14, mchk.mcic);
+		vcpu->stat.deliver_machine_check++;
 		rc = __write_machine_check(vcpu, &mchk);
 	}
 	return rc;

arch/s390/kvm/kvm-s390.c

@@ -88,6 +88,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ "deliver_restart_signal", VCPU_STAT(deliver_restart_signal) },
 	{ "deliver_program_interruption", VCPU_STAT(deliver_program_int) },
 	{ "deliver_io_interrupt", VCPU_STAT(deliver_io_int) },
+	{ "deliver_machine_check", VCPU_STAT(deliver_machine_check) },
 	{ "exit_wait_state", VCPU_STAT(exit_wait_state) },
 	{ "instruction_epsw", VCPU_STAT(instruction_epsw) },
 	{ "instruction_gs", VCPU_STAT(instruction_gs) },