[PATCH v2 18/20] KVM: s390: vsie: 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 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.h |  4 ++++
 arch/s390/kvm/kvm-s390.c         |  4 ++++
 arch/s390/kvm/vsie.c             | 11 +++++++++++
 3 files changed, 19 insertions(+)

diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 932f0437fce5..171472b8d721 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -466,6 +466,10 @@ 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/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 6f458e7b27e3..95eb1494370a 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -86,6 +86,10 @@ 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/vsie.c b/arch/s390/kvm/vsie.c
index 892023dc92d4..8640435c9d5f 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -1104,6 +1104,7 @@ 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_reuseable_vsie_sca(kvm);
@@ -1126,6 +1127,7 @@ 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))
@@ -1983,6 +1985,7 @@ 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) {
@@ -1995,6 +1998,7 @@ 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 = vsie_page_init(vcpu, vsie_page, addr);
@@ -2021,6 +2025,7 @@ 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];
@@ -2041,6 +2046,7 @@ 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);
 
@@ -2058,6 +2064,11 @@ static struct vsie_page *get_vsie_page_cpu_nr(struct kvm_vcpu *vcpu, struct vsie
 			put_vsie_page(vsie_page);
 			return ERR_PTR(rc);
 		}
+
+		if (vsie_page_is_new)
+			vcpu->kvm->stat.vsie_shadow_scb++;
+		else
+			vcpu->kvm->stat.vsie_shadow_scb_reuse++;
 	}
 
 	return vsie_page;

-- 
2.55.0