[PATCH 4/5] vhost: add statistics for IOTLB

[Maxime Coquelin <maxime.coquelin@redhat.com>]

This patch adds statistics for IOTLB hits and misses.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/vhost/vhost.c | 10 +++++++++-
 lib/vhost/vhost.h |  2 ++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index fa708c1f9c..721b3a3247 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -43,6 +43,8 @@ static const struct vhost_vq_stats_name_off vhost_vq_stat_strings[] = {
 	{"size_1024_1518_packets", offsetof(struct vhost_virtqueue, stats.size_bins[6])},
 	{"size_1519_max_packets",  offsetof(struct vhost_virtqueue, stats.size_bins[7])},
 	{"guest_notifications",    offsetof(struct vhost_virtqueue, stats.guest_notifications)},
+	{"iotlb_hits",             offsetof(struct vhost_virtqueue, stats.iotlb_hits)},
+	{"iotlb_misses",           offsetof(struct vhost_virtqueue, stats.iotlb_misses)},
 };
 
 #define VHOST_NB_VQ_STATS RTE_DIM(vhost_vq_stat_strings)
@@ -60,8 +62,14 @@ __vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	tmp_size = *size;
 
 	vva = vhost_user_iotlb_cache_find(vq, iova, &tmp_size, perm);
-	if (tmp_size == *size)
+	if (tmp_size == *size) {
+		if (dev->flags & VIRTIO_DEV_STATS_ENABLED)
+			vq->stats.iotlb_hits++;
 		return vva;
+	}
+
+	if (dev->flags & VIRTIO_DEV_STATS_ENABLED)
+		vq->stats.iotlb_misses++;
 
 	iova += tmp_size;
 
diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
index 13c5c2266d..872675207e 100644
--- a/lib/vhost/vhost.h
+++ b/lib/vhost/vhost.h
@@ -134,6 +134,8 @@ struct virtqueue_stats {
 	/* Size bins in array as RFC 2819, undersized [0], 64 [1], etc */
 	uint64_t size_bins[8];
 	uint64_t guest_notifications;
+	uint64_t iotlb_hits;
+	uint64_t iotlb_misses;
 };
 
 /**
-- 
2.35.1