RISC-V: KVM: Record number of signal exits as a vCPU stat

Record a statistic indicating the number of times a vCPU has exited
due to a pending signal.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org

arch/riscv/include/asm/kvm_host.h

@@ -67,6 +67,7 @@ struct kvm_vcpu_stat {
 	u64 mmio_exit_kernel;
 	u64 csr_exit_user;
 	u64 csr_exit_kernel;
+	u64 signal_exits;
 	u64 exits;
 };
 

arch/riscv/kvm/vcpu.c

@@ -29,6 +29,7 @@ const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
 	STATS_DESC_COUNTER(VCPU, mmio_exit_kernel),
 	STATS_DESC_COUNTER(VCPU, csr_exit_user),
 	STATS_DESC_COUNTER(VCPU, csr_exit_kernel),
+	STATS_DESC_COUNTER(VCPU, signal_exits),
 	STATS_DESC_COUNTER(VCPU, exits)
 };
 
@@ -993,6 +994,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		if (signal_pending(current)) {
 			ret = -EINTR;
 			run->exit_reason = KVM_EXIT_INTR;
+			++vcpu->stat.signal_exits;
 		}
 
 		/*