[PATCH RFC v2 11/11] KVM: s390: Add VSIE shadow stat counters

[Christoph Schlameuss <schlameuss@linux.ibm.com>]

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 cpus.
* vsie_shadow_sca shows the number of allocated system control area
  shadows. Should count upwards between 0 and the max number of cpus.
* vsie_shadow_sca_create shows the number of newly allocated system
  control area 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.h | 4 ++++
 arch/s390/kvm/kvm-s390.c         | 4 ++++
 arch/s390/kvm/vsie.c             | 9 ++++++++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 191b23edf0ac7e9a3e1fd9cdc6fc4c9a9e6769f8..ef7bf2d357f8d289b5f163ec95976c5d270d1380 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -457,6 +457,10 @@ 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_sca;
+	u64 vsie_shadow_sca_create;
+	u64 vsie_shadow_sca_reuse;
 };
 
 struct kvm_arch_memory_slot {
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index e3fc53e33e90be7dab75f73ebd0b949c13d22939..d86bf2206c230ce25fd48610c8305326e260e590 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -79,6 +79,10 @@ 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_sca),
+	STATS_DESC_COUNTER(VM, vsie_shadow_sca_create),
+	STATS_DESC_COUNTER(VM, vsie_shadow_sca_reuse),
 };
 
 const struct kvm_stats_header kvm_vm_stats_header = {
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index cd114df5e119bd289d14037d1f1c5bfe148cf5c7..f7c1a217173cefe93d0914623df08efa14270771 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -767,6 +767,8 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 out:
 	if (rc)
 		unshadow_scb(vcpu, vsie_page);
+	else
+		vcpu->kvm->stat.vsie_shadow_scb++;
 	return rc;
 }
 
@@ -843,8 +845,10 @@ static struct vsie_sca *get_existing_vsie_sca(struct kvm *kvm, hpa_t sca_o_gpa)
 {
 	struct vsie_sca *sca = radix_tree_lookup(&kvm->arch.vsie.osca_to_sca, sca_o_gpa);
 
-	if (sca)
+	if (sca) {
 		WARN_ON_ONCE(atomic_inc_return(&sca->ref_count) < 1);
+		kvm->stat.vsie_shadow_sca_reuse++;
+	}
 	return sca;
 }
 
@@ -958,6 +962,8 @@ static struct vsie_sca *get_vsie_sca(struct kvm_vcpu *vcpu, struct vsie_page *vs
 		sca_new = NULL;
 
 		kvm->arch.vsie.scas[kvm->arch.vsie.sca_count] = sca;
+		kvm->arch.vsie.sca_count++;
+		kvm->stat.vsie_shadow_sca++;
 	} else {
 		/* reuse previously created vsie_sca allocation for different osca */
 		sca = get_free_existing_vsie_sca(kvm);
@@ -992,6 +998,7 @@ static struct vsie_sca *get_vsie_sca(struct kvm_vcpu *vcpu, struct vsie_page *vs
 
 	atomic_set(&sca->ref_count, 1);
 	radix_tree_insert(&kvm->arch.vsie.osca_to_sca, sca->sca_gpa, sca);
+	kvm->stat.vsie_shadow_sca_create++;
 
 out:
 	up_write(&kvm->arch.vsie.ssca_lock);

-- 
2.51.1