[libvirt] [PATCH v2 2/4] vfio/mdev: Add mdev device instances attribute

[Zhenyu Wang <zhenyuw@linux.intel.com>]

For mdev device, create new sysfs attribute "instances" to show
number of instances allocated for possible aggregation type.
For compatibility default or without aggregated allocation, the
number is 1.

Cc: Kirti Wankhede <kwankhede@nvidia.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
---
 drivers/vfio/mdev/mdev_core.c    | 1 +
 drivers/vfio/mdev/mdev_private.h | 1 +
 drivers/vfio/mdev/mdev_sysfs.c   | 8 ++++++++
 3 files changed, 10 insertions(+)

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index e69db302a4f2..f0478fc372d8 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -326,6 +326,7 @@ int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid,
 	mdev->dev.bus     = &mdev_bus_type;
 	mdev->dev.release = mdev_device_release;
 	dev_set_name(&mdev->dev, "%pUl", uuid.b);
+	mdev->type_instances = instances;
 
 	ret = device_register(&mdev->dev);
 	if (ret) {
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index c9d3fe04e273..aa0b4b64c503 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -33,6 +33,7 @@ struct mdev_device {
 	struct kref ref;
 	struct list_head next;
 	struct kobject *type_kobj;
+	unsigned int type_instances;
 	bool active;
 };
 
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index a06e5b7c69d3..5a417a20e774 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -268,10 +268,18 @@ static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
 	return count;
 }
 
+static ssize_t instances_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct mdev_device *mdev = to_mdev_device(dev);
+	return sprintf(buf, "%u\n", mdev->type_instances);
+}
+
 static DEVICE_ATTR_WO(remove);
+static DEVICE_ATTR_RO(instances);
 
 static const struct attribute *mdev_device_attrs[] = {
 	&dev_attr_remove.attr,
+	&dev_attr_instances.attr,
 	NULL,
 };
 
-- 
2.18.0