qmp: add QMP commands for virtio/vhost queue-status

These new commands show the internal status of a VirtIODevice's
VirtQueue and a vhost device's vhost_virtqueue (if active).

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
Message-Id: <1660220684-24909-5-git-send-email-jonah.palmer@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 117 insertions, 0 deletions

diff --git a/hw/virtio/virtio-stub.c b/hw/virtio/virtio-stub.c
index 0b432e8de7..13e5f93652 100644
--- a/hw/virtio/virtio-stub.c
+++ b/hw/virtio/virtio-stub.c
@@ -17,3 +17,17 @@ VirtioStatus *qmp_x_query_virtio_status(const char *path, Error **errp)
 {
     return qmp_virtio_unsupported(errp);
 }
+
+VirtVhostQueueStatus *qmp_x_query_virtio_vhost_queue_status(const char *path,
+                                                            uint16_t queue,
+                                                            Error **errp)
+{
+    return qmp_virtio_unsupported(errp);
+}
+
+VirtQueueStatus *qmp_x_query_virtio_queue_status(const char *path,
+                                                 uint16_t queue,
+                                                 Error **errp)
+{
+    return qmp_virtio_unsupported(errp);
+}
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 6c530567b0..da869e7b51 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -4679,6 +4679,109 @@ VirtioStatus *qmp_x_query_virtio_status(const char *path, Error **errp)
     return status;
 }
 
+VirtVhostQueueStatus *qmp_x_query_virtio_vhost_queue_status(const char *path,
+                                                            uint16_t queue,
+                                                            Error **errp)
+{
+    VirtIODevice *vdev;
+    VirtVhostQueueStatus *status;
+
+    vdev = virtio_device_find(path);
+    if (vdev == NULL) {
+        error_setg(errp, "Path %s is not a VirtIODevice", path);
+        return NULL;
+    }
+
+    if (!vdev->vhost_started) {
+        error_setg(errp, "Error: vhost device has not started yet");
+        return NULL;
+    }
+
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
+    struct vhost_dev *hdev = vdc->get_vhost(vdev);
+
+    if (queue < hdev->vq_index || queue >= hdev->vq_index + hdev->nvqs) {
+        error_setg(errp, "Invalid vhost virtqueue number %d", queue);
+        return NULL;
+    }
+
+    status = g_new0(VirtVhostQueueStatus, 1);
+    status->name = g_strdup(vdev->name);
+    status->kick = hdev->vqs[queue].kick;
+    status->call = hdev->vqs[queue].call;
+    status->desc = (uintptr_t)hdev->vqs[queue].desc;
+    status->avail = (uintptr_t)hdev->vqs[queue].avail;
+    status->used = (uintptr_t)hdev->vqs[queue].used;
+    status->num = hdev->vqs[queue].num;
+    status->desc_phys = hdev->vqs[queue].desc_phys;
+    status->desc_size = hdev->vqs[queue].desc_size;
+    status->avail_phys = hdev->vqs[queue].avail_phys;
+    status->avail_size = hdev->vqs[queue].avail_size;
+    status->used_phys = hdev->vqs[queue].used_phys;
+    status->used_size = hdev->vqs[queue].used_size;
+
+    return status;
+}
+
+VirtQueueStatus *qmp_x_query_virtio_queue_status(const char *path,
+                                                 uint16_t queue,
+                                                 Error **errp)
+{
+    VirtIODevice *vdev;
+    VirtQueueStatus *status;
+
+    vdev = virtio_device_find(path);
+    if (vdev == NULL) {
+        error_setg(errp, "Path %s is not a VirtIODevice", path);
+        return NULL;
+    }
+
+    if (queue >= VIRTIO_QUEUE_MAX || !virtio_queue_get_num(vdev, queue)) {
+        error_setg(errp, "Invalid virtqueue number %d", queue);
+        return NULL;
+    }
+
+    status = g_new0(VirtQueueStatus, 1);
+    status->name = g_strdup(vdev->name);
+    status->queue_index = vdev->vq[queue].queue_index;
+    status->inuse = vdev->vq[queue].inuse;
+    status->vring_num = vdev->vq[queue].vring.num;
+    status->vring_num_default = vdev->vq[queue].vring.num_default;
+    status->vring_align = vdev->vq[queue].vring.align;
+    status->vring_desc = vdev->vq[queue].vring.desc;
+    status->vring_avail = vdev->vq[queue].vring.avail;
+    status->vring_used = vdev->vq[queue].vring.used;
+    status->used_idx = vdev->vq[queue].used_idx;
+    status->signalled_used = vdev->vq[queue].signalled_used;
+    status->signalled_used_valid = vdev->vq[queue].signalled_used_valid;
+
+    if (vdev->vhost_started) {
+        VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
+        struct vhost_dev *hdev = vdc->get_vhost(vdev);
+
+        /* check if vq index exists for vhost as well  */
+        if (queue >= hdev->vq_index && queue < hdev->vq_index + hdev->nvqs) {
+            status->has_last_avail_idx = true;
+
+            int vhost_vq_index =
+                hdev->vhost_ops->vhost_get_vq_index(hdev, queue);
+            struct vhost_vring_state state = {
+                .index = vhost_vq_index,
+            };
+
+            status->last_avail_idx =
+                hdev->vhost_ops->vhost_get_vring_base(hdev, &state);
+        }
+    } else {
+        status->has_shadow_avail_idx = true;
+        status->has_last_avail_idx = true;
+        status->last_avail_idx = vdev->vq[queue].last_avail_idx;
+        status->shadow_avail_idx = vdev->vq[queue].shadow_avail_idx;
+    }
+
+    return status;
+}
+
 static const TypeInfo virtio_device_info = {
     .name = TYPE_VIRTIO_DEVICE,
     .parent = TYPE_DEVICE,