Add new stat counters to VSIE shadowing to be able to verify and monitor
the functionality.

* vsie_shadow_scb shows the number of allocated SIE control block
  shadows. Should count upwards between 0 and the max number of active
  CPUs or configured value.
* vsie_shadow_sca shows the number of allocated system control area
  shadows. Should count upwards between 0 and the max number of active
  CPUs or configured value.
* vsie_shadow_scb_reuse shows the number of reused SIE control block
  shadows.
* vsie_shadow_sca_reuse shows the number of reused system control area
  shadows.

Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
---
 arch/s390/include/asm/kvm_host_s390.h |  4 ++++
 arch/s390/kvm/s390/s390.c             |  4 ++++
 arch/s390/kvm/s390/vsie.c             | 10 ++++++++++
 3 files changed, 18 insertions(+)

diff --git a/arch/s390/include/asm/kvm_host_s390.h b/arch/s390/include/asm/kvm_host_s390.h
index 9768c9dca27c..a19d3a5f550c 100644
--- a/arch/s390/include/asm/kvm_host_s390.h
+++ b/arch/s390/include/asm/kvm_host_s390.h
@@ -412,6 +412,10 @@ struct kvm_vm_stat {
 	u64 gmap_shadow_r3_entry;
 	u64 gmap_shadow_sg_entry;
 	u64 gmap_shadow_pg_entry;
+	u64 vsie_shadow_scb;
+	u64 vsie_shadow_scb_reuse;
+	u64 vsie_shadow_sca;
+	u64 vsie_shadow_sca_reuse;
 };
 
 struct kvm_arch_memory_slot {
diff --git a/arch/s390/kvm/s390/s390.c b/arch/s390/kvm/s390/s390.c
index ae0177d74b11..a1ce75be3955 100644
--- a/arch/s390/kvm/s390/s390.c
+++ b/arch/s390/kvm/s390/s390.c
@@ -87,6 +87,10 @@ const struct kvm_stats_desc kvm_vm_stats_desc[] = {
 	STATS_DESC_COUNTER(VM, gmap_shadow_r3_entry),
 	STATS_DESC_COUNTER(VM, gmap_shadow_sg_entry),
 	STATS_DESC_COUNTER(VM, gmap_shadow_pg_entry),
+	STATS_DESC_COUNTER(VM, vsie_shadow_scb),
+	STATS_DESC_COUNTER(VM, vsie_shadow_scb_reuse),
+	STATS_DESC_COUNTER(VM, vsie_shadow_sca),
+	STATS_DESC_COUNTER(VM, vsie_shadow_sca_reuse),
 };
 
 const struct kvm_stats_header kvm_vm_stats_header = {
diff --git a/arch/s390/kvm/s390/vsie.c b/arch/s390/kvm/s390/vsie.c
index fe94587511b0..335ed1a927aa 100644
--- a/arch/s390/kvm/s390/vsie.c
+++ b/arch/s390/kvm/s390/vsie.c
@@ -1133,6 +1133,7 @@ static struct vsie_sca *get_vsie_sca(struct kvm_vcpu *vcpu, struct kvm_s390_sie_
 		kvm->arch.vsie.scas[kvm->arch.vsie.sca_count] = vsie_sca;
 		kvm->arch.vsie.sca_count++;
 		atomic_set(&vsie_sca->ref_count, 1);
+		kvm->stat.vsie_shadow_sca++;
 	} else {
 		/* reuse previously created vsie_sca allocation for different osca */
 		vsie_sca = get_vsie_sca_unused(kvm);
@@ -1154,6 +1155,7 @@ static struct vsie_sca *get_vsie_sca(struct kvm_vcpu *vcpu, struct kvm_s390_sie_
 		}
 		unpin_sca(kvm, vsie_sca);
 		clear_vsie_sca(vsie_sca);
+		kvm->stat.vsie_shadow_sca_reuse++;
 	}
 
 	if (sie_uses_esca(scb_o))
@@ -2006,6 +2008,7 @@ static struct vsie_page *get_vsie_page(struct kvm_vcpu *vcpu, unsigned long addr
 		vsie_page_new = NULL;
 		WRITE_ONCE(kvm->arch.vsie.pages[kvm->arch.vsie.page_count], vsie_page);
 		kvm->arch.vsie.page_count++;
+		kvm->stat.vsie_shadow_scb++;
 	} else {
 		/* reuse an existing entry that belongs to nobody */
 		while (true) {
@@ -2018,6 +2021,7 @@ static struct vsie_page *get_vsie_page(struct kvm_vcpu *vcpu, unsigned long addr
 		}
 
 		unpin_scb(kvm, vsie_page);
+		kvm->stat.vsie_shadow_scb_reuse++;
 	}
 
 	rc = init_vsie_page(vcpu, vsie_page, addr);
@@ -2043,6 +2047,7 @@ static struct vsie_page *get_vsie_page_cpu_nr(struct kvm_vcpu *vcpu, struct vsie
 					      gpa_t scb_gpa, u16 cpu_nr)
 {
 	struct vsie_page *vsie_page, *vsie_page_new = NULL;
+	bool vsie_page_is_new = true;
 	int rc;
 
 	vsie_page = vsie_sca->pages[cpu_nr];
@@ -2063,6 +2068,7 @@ static struct vsie_page *get_vsie_page_cpu_nr(struct kvm_vcpu *vcpu, struct vsie
 		}
 	}
 	if (vsie_page != vsie_page_new) {
+		vsie_page_is_new = false;
 		if (vsie_page_new)
 			free_vsie_page(vsie_page_new);
 
@@ -2076,6 +2082,10 @@ static struct vsie_page *get_vsie_page_cpu_nr(struct kvm_vcpu *vcpu, struct vsie
 			unpin_scb(vcpu->kvm, vsie_page);
 			rc = init_vsie_page(vcpu, vsie_page, scb_gpa);
 		}
+		if (vsie_page_is_new)
+			vcpu->kvm->stat.vsie_shadow_scb++;
+		else
+			vcpu->kvm->stat.vsie_shadow_scb_reuse++;
 		if (rc) {
 			put_vsie_page(vsie_page);
 			return ERR_PTR(rc);

-- 
2.55.0