v4.19.13 snapshot.
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
new file mode 100644
index 0000000..59e36ef
--- /dev/null
+++ b/drivers/virtio/virtio.c
@@ -0,0 +1,444 @@
+#include <linux/virtio.h>
+#include <linux/spinlock.h>
+#include <linux/virtio_config.h>
+#include <linux/module.h>
+#include <linux/idr.h>
+#include <uapi/linux/virtio_ids.h>
+
+/* Unique numbering for virtio devices. */
+static DEFINE_IDA(virtio_index_ida);
+
+static ssize_t device_show(struct device *_d,
+ struct device_attribute *attr, char *buf)
+{
+ struct virtio_device *dev = dev_to_virtio(_d);
+ return sprintf(buf, "0x%04x\n", dev->id.device);
+}
+static DEVICE_ATTR_RO(device);
+
+static ssize_t vendor_show(struct device *_d,
+ struct device_attribute *attr, char *buf)
+{
+ struct virtio_device *dev = dev_to_virtio(_d);
+ return sprintf(buf, "0x%04x\n", dev->id.vendor);
+}
+static DEVICE_ATTR_RO(vendor);
+
+static ssize_t status_show(struct device *_d,
+ struct device_attribute *attr, char *buf)
+{
+ struct virtio_device *dev = dev_to_virtio(_d);
+ return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
+}
+static DEVICE_ATTR_RO(status);
+
+static ssize_t modalias_show(struct device *_d,
+ struct device_attribute *attr, char *buf)
+{
+ struct virtio_device *dev = dev_to_virtio(_d);
+ return sprintf(buf, "virtio:d%08Xv%08X\n",
+ dev->id.device, dev->id.vendor);
+}
+static DEVICE_ATTR_RO(modalias);
+
+static ssize_t features_show(struct device *_d,
+ struct device_attribute *attr, char *buf)
+{
+ struct virtio_device *dev = dev_to_virtio(_d);
+ unsigned int i;
+ ssize_t len = 0;
+
+ /* We actually represent this as a bitstring, as it could be
+ * arbitrary length in future. */
+ for (i = 0; i < sizeof(dev->features)*8; i++)
+ len += sprintf(buf+len, "%c",
+ __virtio_test_bit(dev, i) ? '1' : '0');
+ len += sprintf(buf+len, "\n");
+ return len;
+}
+static DEVICE_ATTR_RO(features);
+
+static struct attribute *virtio_dev_attrs[] = {
+ &dev_attr_device.attr,
+ &dev_attr_vendor.attr,
+ &dev_attr_status.attr,
+ &dev_attr_modalias.attr,
+ &dev_attr_features.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(virtio_dev);
+
+static inline int virtio_id_match(const struct virtio_device *dev,
+ const struct virtio_device_id *id)
+{
+ if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
+ return 0;
+
+ return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
+}
+
+/* This looks through all the IDs a driver claims to support. If any of them
+ * match, we return 1 and the kernel will call virtio_dev_probe(). */
+static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
+{
+ unsigned int i;
+ struct virtio_device *dev = dev_to_virtio(_dv);
+ const struct virtio_device_id *ids;
+
+ ids = drv_to_virtio(_dr)->id_table;
+ for (i = 0; ids[i].device; i++)
+ if (virtio_id_match(dev, &ids[i]))
+ return 1;
+ return 0;
+}
+
+static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
+{
+ struct virtio_device *dev = dev_to_virtio(_dv);
+
+ return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
+ dev->id.device, dev->id.vendor);
+}
+
+void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
+ unsigned int fbit)
+{
+ unsigned int i;
+ struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
+
+ for (i = 0; i < drv->feature_table_size; i++)
+ if (drv->feature_table[i] == fbit)
+ return;
+
+ if (drv->feature_table_legacy) {
+ for (i = 0; i < drv->feature_table_size_legacy; i++)
+ if (drv->feature_table_legacy[i] == fbit)
+ return;
+ }
+
+ BUG();
+}
+EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
+
+static void __virtio_config_changed(struct virtio_device *dev)
+{
+ struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+
+ if (!dev->config_enabled)
+ dev->config_change_pending = true;
+ else if (drv && drv->config_changed)
+ drv->config_changed(dev);
+}
+
+void virtio_config_changed(struct virtio_device *dev)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev->config_lock, flags);
+ __virtio_config_changed(dev);
+ spin_unlock_irqrestore(&dev->config_lock, flags);
+}
+EXPORT_SYMBOL_GPL(virtio_config_changed);
+
+void virtio_config_disable(struct virtio_device *dev)
+{
+ spin_lock_irq(&dev->config_lock);
+ dev->config_enabled = false;
+ spin_unlock_irq(&dev->config_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_config_disable);
+
+void virtio_config_enable(struct virtio_device *dev)
+{
+ spin_lock_irq(&dev->config_lock);
+ dev->config_enabled = true;
+ if (dev->config_change_pending)
+ __virtio_config_changed(dev);
+ dev->config_change_pending = false;
+ spin_unlock_irq(&dev->config_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_config_enable);
+
+void virtio_add_status(struct virtio_device *dev, unsigned int status)
+{
+ dev->config->set_status(dev, dev->config->get_status(dev) | status);
+}
+EXPORT_SYMBOL_GPL(virtio_add_status);
+
+int virtio_finalize_features(struct virtio_device *dev)
+{
+ int ret = dev->config->finalize_features(dev);
+ unsigned status;
+
+ if (ret)
+ return ret;
+
+ if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
+ return 0;
+
+ virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
+ status = dev->config->get_status(dev);
+ if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
+ dev_err(&dev->dev, "virtio: device refuses features: %x\n",
+ status);
+ return -ENODEV;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_finalize_features);
+
+static int virtio_dev_probe(struct device *_d)
+{
+ int err, i;
+ struct virtio_device *dev = dev_to_virtio(_d);
+ struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+ u64 device_features;
+ u64 driver_features;
+ u64 driver_features_legacy;
+
+ /* We have a driver! */
+ virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
+
+ /* Figure out what features the device supports. */
+ device_features = dev->config->get_features(dev);
+
+ /* Figure out what features the driver supports. */
+ driver_features = 0;
+ for (i = 0; i < drv->feature_table_size; i++) {
+ unsigned int f = drv->feature_table[i];
+ BUG_ON(f >= 64);
+ driver_features |= (1ULL << f);
+ }
+
+ /* Some drivers have a separate feature table for virtio v1.0 */
+ if (drv->feature_table_legacy) {
+ driver_features_legacy = 0;
+ for (i = 0; i < drv->feature_table_size_legacy; i++) {
+ unsigned int f = drv->feature_table_legacy[i];
+ BUG_ON(f >= 64);
+ driver_features_legacy |= (1ULL << f);
+ }
+ } else {
+ driver_features_legacy = driver_features;
+ }
+
+ if (device_features & (1ULL << VIRTIO_F_VERSION_1))
+ dev->features = driver_features & device_features;
+ else
+ dev->features = driver_features_legacy & device_features;
+
+ /* Transport features always preserved to pass to finalize_features. */
+ for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
+ if (device_features & (1ULL << i))
+ __virtio_set_bit(dev, i);
+
+ if (drv->validate) {
+ err = drv->validate(dev);
+ if (err)
+ goto err;
+ }
+
+ err = virtio_finalize_features(dev);
+ if (err)
+ goto err;
+
+ err = drv->probe(dev);
+ if (err)
+ goto err;
+
+ /* If probe didn't do it, mark device DRIVER_OK ourselves. */
+ if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
+ virtio_device_ready(dev);
+
+ if (drv->scan)
+ drv->scan(dev);
+
+ virtio_config_enable(dev);
+
+ return 0;
+err:
+ virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
+ return err;
+
+}
+
+static int virtio_dev_remove(struct device *_d)
+{
+ struct virtio_device *dev = dev_to_virtio(_d);
+ struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+
+ virtio_config_disable(dev);
+
+ drv->remove(dev);
+
+ /* Driver should have reset device. */
+ WARN_ON_ONCE(dev->config->get_status(dev));
+
+ /* Acknowledge the device's existence again. */
+ virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
+ return 0;
+}
+
+static struct bus_type virtio_bus = {
+ .name = "virtio",
+ .match = virtio_dev_match,
+ .dev_groups = virtio_dev_groups,
+ .uevent = virtio_uevent,
+ .probe = virtio_dev_probe,
+ .remove = virtio_dev_remove,
+};
+
+int register_virtio_driver(struct virtio_driver *driver)
+{
+ /* Catch this early. */
+ BUG_ON(driver->feature_table_size && !driver->feature_table);
+ driver->driver.bus = &virtio_bus;
+ return driver_register(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(register_virtio_driver);
+
+void unregister_virtio_driver(struct virtio_driver *driver)
+{
+ driver_unregister(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(unregister_virtio_driver);
+
+/**
+ * register_virtio_device - register virtio device
+ * @dev : virtio device to be registered
+ *
+ * On error, the caller must call put_device on &@dev->dev (and not kfree),
+ * as another code path may have obtained a reference to @dev.
+ *
+ * Returns: 0 on suceess, -error on failure
+ */
+int register_virtio_device(struct virtio_device *dev)
+{
+ int err;
+
+ dev->dev.bus = &virtio_bus;
+ device_initialize(&dev->dev);
+
+ /* Assign a unique device index and hence name. */
+ err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
+ if (err < 0)
+ goto out;
+
+ dev->index = err;
+ dev_set_name(&dev->dev, "virtio%u", dev->index);
+
+ spin_lock_init(&dev->config_lock);
+ dev->config_enabled = false;
+ dev->config_change_pending = false;
+
+ /* We always start by resetting the device, in case a previous
+ * driver messed it up. This also tests that code path a little. */
+ dev->config->reset(dev);
+
+ /* Acknowledge that we've seen the device. */
+ virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
+
+ INIT_LIST_HEAD(&dev->vqs);
+
+ /*
+ * device_add() causes the bus infrastructure to look for a matching
+ * driver.
+ */
+ err = device_add(&dev->dev);
+ if (err)
+ ida_simple_remove(&virtio_index_ida, dev->index);
+out:
+ if (err)
+ virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
+ return err;
+}
+EXPORT_SYMBOL_GPL(register_virtio_device);
+
+void unregister_virtio_device(struct virtio_device *dev)
+{
+ int index = dev->index; /* save for after device release */
+
+ device_unregister(&dev->dev);
+ ida_simple_remove(&virtio_index_ida, index);
+}
+EXPORT_SYMBOL_GPL(unregister_virtio_device);
+
+#ifdef CONFIG_PM_SLEEP
+int virtio_device_freeze(struct virtio_device *dev)
+{
+ struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+
+ virtio_config_disable(dev);
+
+ dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
+
+ if (drv && drv->freeze)
+ return drv->freeze(dev);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_device_freeze);
+
+int virtio_device_restore(struct virtio_device *dev)
+{
+ struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
+ int ret;
+
+ /* We always start by resetting the device, in case a previous
+ * driver messed it up. */
+ dev->config->reset(dev);
+
+ /* Acknowledge that we've seen the device. */
+ virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
+
+ /* Maybe driver failed before freeze.
+ * Restore the failed status, for debugging. */
+ if (dev->failed)
+ virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
+
+ if (!drv)
+ return 0;
+
+ /* We have a driver! */
+ virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
+
+ ret = virtio_finalize_features(dev);
+ if (ret)
+ goto err;
+
+ if (drv->restore) {
+ ret = drv->restore(dev);
+ if (ret)
+ goto err;
+ }
+
+ /* Finally, tell the device we're all set */
+ virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
+
+ virtio_config_enable(dev);
+
+ return 0;
+
+err:
+ virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(virtio_device_restore);
+#endif
+
+static int virtio_init(void)
+{
+ if (bus_register(&virtio_bus) != 0)
+ panic("virtio bus registration failed");
+ return 0;
+}
+
+static void __exit virtio_exit(void)
+{
+ bus_unregister(&virtio_bus);
+ ida_destroy(&virtio_index_ida);
+}
+core_initcall(virtio_init);
+module_exit(virtio_exit);
+
+MODULE_LICENSE("GPL");