vfio/mdev: consolidate all the available_instance sysfs into the core code

Every driver just print a number, simply add a method to the mdev_driver
to return it and provide a standard sysfs show function.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Jason Gunthorpe <[e-mail]>
Reviewed-by: Kevin Tian <[e-mail]>
Reviewed-by: Kirti Wankhede <[e-mail]>
Reviewed-by: Eric Farman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alex Williamson <[e-mail]>

Documentation/driver-api/vfio-mediated-device.rst

···
      struct mdev_driver {
 	     int  (*probe)  (struct mdev_device *dev);
 	     void (*remove) (struct mdev_device *dev);
+	     unsigned int (*get_available)(struct mdev_type *mtype);
 	     const struct attribute * const *types_attrs;
 	     struct device_driver    driver;
      };
···
 
 * available_instances
 
-  This attribute should show the number of devices of type <type-id> that can be
+  This attribute shows the number of devices of type <type-id> that can be
   created.
 
 * [device]

drivers/gpu/drm/i915/gvt/gvt.h

···
 	struct mdev_type type;
 	char name[16];
 	const struct intel_vgpu_config *conf;
-	unsigned int avail_instance;
 };
 
 struct intel_gvt {

drivers/gpu/drm/i915/gvt/kvmgt.c

···
 		struct kvm_memory_slot *slot,
 		struct kvm_page_track_notifier_node *node);
 
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
-{
-	struct intel_vgpu_type *type =
-		container_of(mtype, struct intel_vgpu_type, type);
-
-	return sprintf(buf, "%u\n", type->avail_instance);
-}
-
 static ssize_t description_show(struct mdev_type *mtype,
 				struct mdev_type_attribute *attr, char *buf)
 {
···
 		       type->conf->weight);
 }
 
-static MDEV_TYPE_ATTR_RO(available_instances);
 static MDEV_TYPE_ATTR_RO(description);
 
 static const struct attribute *gvt_type_attrs[] = {
-	&mdev_type_attr_available_instances.attr,
 	&mdev_type_attr_description.attr,
 	NULL,
 };
···
 	vfio_put_device(&vgpu->vfio_device);
 }
 
+static unsigned int intel_vgpu_get_available(struct mdev_type *mtype)
+{
+	struct intel_vgpu_type *type =
+		container_of(mtype, struct intel_vgpu_type, type);
+	struct intel_gvt *gvt = kdev_to_i915(mtype->parent->dev)->gvt;
+	unsigned int low_gm_avail, high_gm_avail, fence_avail;
+
+	mutex_lock(&gvt->lock);
+	low_gm_avail = gvt_aperture_sz(gvt) - HOST_LOW_GM_SIZE -
+		gvt->gm.vgpu_allocated_low_gm_size;
+	high_gm_avail = gvt_hidden_sz(gvt) - HOST_HIGH_GM_SIZE -
+		gvt->gm.vgpu_allocated_high_gm_size;
+	fence_avail = gvt_fence_sz(gvt) - HOST_FENCE -
+		gvt->fence.vgpu_allocated_fence_num;
+	mutex_unlock(&gvt->lock);
+
+	return min3(low_gm_avail / type->conf->low_mm,
+		    high_gm_avail / type->conf->high_mm,
+		    fence_avail / type->conf->fence);
+}
+
 static struct mdev_driver intel_vgpu_mdev_driver = {
 	.device_api	= VFIO_DEVICE_API_PCI_STRING,
 	.driver = {
···
 	},
 	.probe		= intel_vgpu_probe,
 	.remove		= intel_vgpu_remove,
+	.get_available	= intel_vgpu_get_available,
 	.types_attrs	= gvt_type_attrs,
 };
 

drivers/gpu/drm/i915/gvt/vgpu.c

···
 		sprintf(gvt->types[i].name, "GVTg_V%u_%s",
 			GRAPHICS_VER(gvt->gt->i915) == 8 ? 4 : 5, conf->name);
 		gvt->types[i].conf = conf;
-		gvt->types[i].avail_instance = min(low_avail / conf->low_mm,
-						   high_avail / conf->high_mm);
 
 		gvt_dbg_core("type[%d]: %s avail %u low %u high %u fence %u weight %u res %s\n",
-			     i, gvt->types[i].name, gvt->types[i].avail_instance,
+			     i, gvt->types[i].name,
+			     min(low_avail / conf->low_mm,
+				 high_avail / conf->high_mm),
 			     conf->low_mm, conf->high_mm, conf->fence,
 			     conf->weight, vgpu_edid_str(conf->edid));
 
···
 {
 	kfree(gvt->mdev_types);
 	kfree(gvt->types);
-}
-
-static void intel_gvt_update_vgpu_types(struct intel_gvt *gvt)
-{
-	int i;
-	unsigned int low_gm_avail, high_gm_avail, fence_avail;
-	unsigned int low_gm_min, high_gm_min, fence_min;
-
-	/* Need to depend on maxium hw resource size but keep on
-	 * static config for now.
-	 */
-	low_gm_avail = gvt_aperture_sz(gvt) - HOST_LOW_GM_SIZE -
-		gvt->gm.vgpu_allocated_low_gm_size;
-	high_gm_avail = gvt_hidden_sz(gvt) - HOST_HIGH_GM_SIZE -
-		gvt->gm.vgpu_allocated_high_gm_size;
-	fence_avail = gvt_fence_sz(gvt) - HOST_FENCE -
-		gvt->fence.vgpu_allocated_fence_num;
-
-	for (i = 0; i < gvt->num_types; i++) {
-		low_gm_min = low_gm_avail / gvt->types[i].conf->low_mm;
-		high_gm_min = high_gm_avail / gvt->types[i].conf->high_mm;
-		fence_min = fence_avail / gvt->types[i].conf->fence;
-		gvt->types[i].avail_instance = min(min(low_gm_min, high_gm_min),
-						   fence_min);
-
-		gvt_dbg_core("update type[%d]: %s avail %u low %u high %u fence %u\n",
-		       i, gvt->types[i].name,
-		       gvt->types[i].avail_instance, gvt->types[i].conf->low_mm,
-		       gvt->types[i].conf->high_mm, gvt->types[i].conf->fence);
-	}
 }
 
 /**
···
 	intel_vgpu_clean_mmio(vgpu);
 	intel_vgpu_dmabuf_cleanup(vgpu);
 	mutex_unlock(&vgpu->vgpu_lock);
-
-	mutex_lock(&gvt->lock);
-	intel_gvt_update_vgpu_types(gvt);
-	mutex_unlock(&gvt->lock);
 }
 
 #define IDLE_VGPU_IDR 0
···
 	if (ret)
 		goto out_clean_sched_policy;
 
-	intel_gvt_update_vgpu_types(gvt);
 	intel_gvt_update_reg_whitelist(vgpu);
 	mutex_unlock(&gvt->lock);
 	return 0;

drivers/s390/cio/vfio_ccw_ops.c

···
 	vfio_ccw_mdev_reset(private);
 }
 
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
+static unsigned int vfio_ccw_get_available(struct mdev_type *mtype)
 {
 	struct vfio_ccw_private *private = dev_get_drvdata(mtype->parent->dev);
 
-	return sprintf(buf, "%d\n", atomic_read(&private->avail));
+	return atomic_read(&private->avail);
 }
-static MDEV_TYPE_ATTR_RO(available_instances);
-
-static const struct attribute *mdev_types_attrs[] = {
-	&mdev_type_attr_available_instances.attr,
-	NULL,
-};
 
 static int vfio_ccw_mdev_init_dev(struct vfio_device *vdev)
 {
···
 	},
 	.probe = vfio_ccw_mdev_probe,
 	.remove = vfio_ccw_mdev_remove,
-	.types_attrs = mdev_types_attrs,
+	.get_available = vfio_ccw_get_available,
 };

drivers/s390/crypto/vfio_ap_ops.c

···
 	vfio_put_device(&matrix_mdev->vdev);
 }
 
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
+static unsigned int vfio_ap_mdev_get_available(struct mdev_type *mtype)
 {
-	return sprintf(buf, "%d\n",
-		       atomic_read(&matrix_dev->available_instances));
+	return atomic_read(&matrix_dev->available_instances);
 }
-
-static MDEV_TYPE_ATTR_RO(available_instances);
-
-static const struct attribute *vfio_ap_mdev_type_attrs[] = {
-	&mdev_type_attr_available_instances.attr,
-	NULL,
-};
 
 #define MDEV_SHARING_ERR "Userspace may not re-assign queue %02lx.%04lx " \
 			 "already assigned to %s"
···
 	},
 	.probe = vfio_ap_mdev_probe,
 	.remove = vfio_ap_mdev_remove,
-	.types_attrs = vfio_ap_mdev_type_attrs,
+	.get_available = vfio_ap_mdev_get_available,
 };
 
 int vfio_ap_mdev_register(void)

drivers/vfio/mdev/mdev_sysfs.c

···
 
 static MDEV_TYPE_ATTR_RO(name);
 
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
+{
+	struct mdev_driver *drv = mtype->parent->mdev_driver;
+
+	return sysfs_emit(buf, "%u\n", drv->get_available(mtype));
+}
+static MDEV_TYPE_ATTR_RO(available_instances);
+
 static struct attribute *mdev_types_core_attrs[] = {
 	&mdev_type_attr_create.attr,
 	&mdev_type_attr_device_api.attr,
 	&mdev_type_attr_name.attr,
+	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
 

include/linux/mdev.h

···
  * @device_api: string to return for the device_api sysfs
  * @probe: called when new device created
  * @remove: called when device removed
+ * @get_available: Return the max number of instances that can be created
  * @types_attrs: attributes to the type kobjects.
  * @driver: device driver structure
  **/
···
 	const char *device_api;
 	int (*probe)(struct mdev_device *dev);
 	void (*remove)(struct mdev_device *dev);
+	unsigned int (*get_available)(struct mdev_type *mtype);
 	const struct attribute * const *types_attrs;
 	struct device_driver driver;
 };

samples/vfio-mdev/mbochs.c

···
 }
 static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
+static unsigned int mbochs_get_available(struct mdev_type *mtype)
 {
 	struct mbochs_type *type =
 		container_of(mtype, struct mbochs_type, type);
-	int count = atomic_read(&mbochs_avail_mbytes) / type->mbytes;
 
-	return sprintf(buf, "%d\n", count);
+	return atomic_read(&mbochs_avail_mbytes) / type->mbytes;
 }
-static MDEV_TYPE_ATTR_RO(available_instances);
 
 static const struct attribute *mdev_types_attrs[] = {
 	&mdev_type_attr_description.attr,
-	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
 
···
 	},
 	.probe = mbochs_probe,
 	.remove	= mbochs_remove,
+	.get_available = mbochs_get_available,
 	.types_attrs = mdev_types_attrs,
 };
 

samples/vfio-mdev/mdpy.c

···
 }
 static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
+static unsigned int mdpy_get_available(struct mdev_type *mtype)
 {
-	return sprintf(buf, "%d\n", max_devices - mdpy_count);
+	return max_devices - mdpy_count;
 }
-static MDEV_TYPE_ATTR_RO(available_instances);
 
 static const struct attribute *mdev_types_attrs[] = {
 	&mdev_type_attr_description.attr,
-	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
 
···
 	},
 	.probe = mdpy_probe,
 	.remove	= mdpy_remove,
+	.get_available = mdpy_get_available,
 	.types_attrs = mdev_types_attrs,
 };
 

samples/vfio-mdev/mtty.c

···
 	NULL,
 };
 
-static ssize_t available_instances_show(struct mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
+static unsigned int mtty_get_available(struct mdev_type *mtype)
 {
 	struct mtty_type *type = container_of(mtype, struct mtty_type, type);
 
-	return sprintf(buf, "%d\n", atomic_read(&mdev_avail_ports) /
-			type->nr_ports);
+	return atomic_read(&mdev_avail_ports) / type->nr_ports;
 }
-
-static MDEV_TYPE_ATTR_RO(available_instances);
-
-static const struct attribute *mdev_types_attrs[] = {
-	&mdev_type_attr_available_instances.attr,
-	NULL,
-};
 
 static const struct vfio_device_ops mtty_dev_ops = {
 	.name = "vfio-mtty",
···
 	},
 	.probe = mtty_probe,
 	.remove	= mtty_remove,
-	.types_attrs = mdev_types_attrs,
+	.get_available = mtty_get_available,
 };
 
 static void mtty_device_release(struct device *dev)