572 lines
14 KiB
C
572 lines
14 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/virtio.h>
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#include <linux/spinlock.h>
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#include <linux/virtio_config.h>
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#include <linux/virtio_anchor.h>
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#include <linux/module.h>
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#include <linux/idr.h>
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#include <linux/of.h>
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#include <uapi/linux/virtio_ids.h>
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/* Unique numbering for virtio devices. */
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static DEFINE_IDA(virtio_index_ida);
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static ssize_t device_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = dev_to_virtio(_d);
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return sysfs_emit(buf, "0x%04x\n", dev->id.device);
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}
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static DEVICE_ATTR_RO(device);
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static ssize_t vendor_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = dev_to_virtio(_d);
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return sysfs_emit(buf, "0x%04x\n", dev->id.vendor);
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}
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static DEVICE_ATTR_RO(vendor);
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static ssize_t status_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = dev_to_virtio(_d);
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return sysfs_emit(buf, "0x%08x\n", dev->config->get_status(dev));
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}
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static DEVICE_ATTR_RO(status);
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static ssize_t modalias_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = dev_to_virtio(_d);
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return sysfs_emit(buf, "virtio:d%08Xv%08X\n",
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dev->id.device, dev->id.vendor);
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}
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static DEVICE_ATTR_RO(modalias);
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static ssize_t features_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = dev_to_virtio(_d);
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unsigned int i;
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ssize_t len = 0;
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/* We actually represent this as a bitstring, as it could be
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* arbitrary length in future. */
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for (i = 0; i < sizeof(dev->features)*8; i++)
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len += sysfs_emit_at(buf, len, "%c",
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__virtio_test_bit(dev, i) ? '1' : '0');
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len += sysfs_emit_at(buf, len, "\n");
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return len;
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}
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static DEVICE_ATTR_RO(features);
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static struct attribute *virtio_dev_attrs[] = {
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&dev_attr_device.attr,
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&dev_attr_vendor.attr,
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&dev_attr_status.attr,
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&dev_attr_modalias.attr,
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&dev_attr_features.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(virtio_dev);
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static inline int virtio_id_match(const struct virtio_device *dev,
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const struct virtio_device_id *id)
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{
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if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
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return 0;
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return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
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}
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/* This looks through all the IDs a driver claims to support. If any of them
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* match, we return 1 and the kernel will call virtio_dev_probe(). */
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static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
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{
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unsigned int i;
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struct virtio_device *dev = dev_to_virtio(_dv);
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const struct virtio_device_id *ids;
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ids = drv_to_virtio(_dr)->id_table;
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for (i = 0; ids[i].device; i++)
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if (virtio_id_match(dev, &ids[i]))
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return 1;
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return 0;
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}
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static int virtio_uevent(const struct device *_dv, struct kobj_uevent_env *env)
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{
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const struct virtio_device *dev = dev_to_virtio(_dv);
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return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
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dev->id.device, dev->id.vendor);
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}
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void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
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unsigned int fbit)
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{
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unsigned int i;
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struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
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for (i = 0; i < drv->feature_table_size; i++)
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if (drv->feature_table[i] == fbit)
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return;
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if (drv->feature_table_legacy) {
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for (i = 0; i < drv->feature_table_size_legacy; i++)
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if (drv->feature_table_legacy[i] == fbit)
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return;
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}
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BUG();
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}
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EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
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static void __virtio_config_changed(struct virtio_device *dev)
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{
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struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
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if (!dev->config_enabled)
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dev->config_change_pending = true;
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else if (drv && drv->config_changed)
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drv->config_changed(dev);
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}
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void virtio_config_changed(struct virtio_device *dev)
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{
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unsigned long flags;
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spin_lock_irqsave(&dev->config_lock, flags);
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__virtio_config_changed(dev);
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spin_unlock_irqrestore(&dev->config_lock, flags);
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}
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EXPORT_SYMBOL_GPL(virtio_config_changed);
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static void virtio_config_disable(struct virtio_device *dev)
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{
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spin_lock_irq(&dev->config_lock);
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dev->config_enabled = false;
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spin_unlock_irq(&dev->config_lock);
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}
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static void virtio_config_enable(struct virtio_device *dev)
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{
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spin_lock_irq(&dev->config_lock);
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dev->config_enabled = true;
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if (dev->config_change_pending)
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__virtio_config_changed(dev);
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dev->config_change_pending = false;
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spin_unlock_irq(&dev->config_lock);
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}
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void virtio_add_status(struct virtio_device *dev, unsigned int status)
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{
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might_sleep();
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dev->config->set_status(dev, dev->config->get_status(dev) | status);
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}
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EXPORT_SYMBOL_GPL(virtio_add_status);
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/* Do some validation, then set FEATURES_OK */
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static int virtio_features_ok(struct virtio_device *dev)
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{
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unsigned int status;
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might_sleep();
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if (virtio_check_mem_acc_cb(dev)) {
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if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
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dev_warn(&dev->dev,
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"device must provide VIRTIO_F_VERSION_1\n");
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return -ENODEV;
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}
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if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) {
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dev_warn(&dev->dev,
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"device must provide VIRTIO_F_ACCESS_PLATFORM\n");
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return -ENODEV;
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}
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}
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if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
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return 0;
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virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
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status = dev->config->get_status(dev);
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if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
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dev_err(&dev->dev, "virtio: device refuses features: %x\n",
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status);
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return -ENODEV;
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}
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return 0;
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}
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/**
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* virtio_reset_device - quiesce device for removal
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* @dev: the device to reset
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*
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* Prevents device from sending interrupts and accessing memory.
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*
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* Generally used for cleanup during driver / device removal.
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*
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* Once this has been invoked, caller must ensure that
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* virtqueue_notify / virtqueue_kick are not in progress.
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*
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* Note: this guarantees that vq callbacks are not in progress, however caller
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* is responsible for preventing access from other contexts, such as a system
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* call/workqueue/bh. Invoking virtio_break_device then flushing any such
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* contexts is one way to handle that.
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* */
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void virtio_reset_device(struct virtio_device *dev)
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{
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#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
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/*
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* The below virtio_synchronize_cbs() guarantees that any
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* interrupt for this line arriving after
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* virtio_synchronize_vqs() has completed is guaranteed to see
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* vq->broken as true.
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*/
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virtio_break_device(dev);
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virtio_synchronize_cbs(dev);
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#endif
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dev->config->reset(dev);
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}
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EXPORT_SYMBOL_GPL(virtio_reset_device);
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static int virtio_dev_probe(struct device *_d)
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{
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int err, i;
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struct virtio_device *dev = dev_to_virtio(_d);
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struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
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u64 device_features;
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u64 driver_features;
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u64 driver_features_legacy;
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/* We have a driver! */
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virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
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/* Figure out what features the device supports. */
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device_features = dev->config->get_features(dev);
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/* Figure out what features the driver supports. */
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driver_features = 0;
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for (i = 0; i < drv->feature_table_size; i++) {
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unsigned int f = drv->feature_table[i];
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BUG_ON(f >= 64);
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driver_features |= (1ULL << f);
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}
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/* Some drivers have a separate feature table for virtio v1.0 */
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if (drv->feature_table_legacy) {
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driver_features_legacy = 0;
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for (i = 0; i < drv->feature_table_size_legacy; i++) {
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unsigned int f = drv->feature_table_legacy[i];
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BUG_ON(f >= 64);
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driver_features_legacy |= (1ULL << f);
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}
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} else {
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driver_features_legacy = driver_features;
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}
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if (device_features & (1ULL << VIRTIO_F_VERSION_1))
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dev->features = driver_features & device_features;
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else
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dev->features = driver_features_legacy & device_features;
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/* Transport features always preserved to pass to finalize_features. */
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for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
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if (device_features & (1ULL << i))
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__virtio_set_bit(dev, i);
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err = dev->config->finalize_features(dev);
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if (err)
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goto err;
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if (drv->validate) {
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u64 features = dev->features;
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err = drv->validate(dev);
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if (err)
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goto err;
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/* Did validation change any features? Then write them again. */
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if (features != dev->features) {
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err = dev->config->finalize_features(dev);
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if (err)
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goto err;
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}
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}
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err = virtio_features_ok(dev);
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if (err)
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goto err;
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err = drv->probe(dev);
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if (err)
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goto err;
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/* If probe didn't do it, mark device DRIVER_OK ourselves. */
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if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
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virtio_device_ready(dev);
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if (drv->scan)
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drv->scan(dev);
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virtio_config_enable(dev);
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return 0;
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err:
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virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
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return err;
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}
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static void virtio_dev_remove(struct device *_d)
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{
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struct virtio_device *dev = dev_to_virtio(_d);
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struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
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virtio_config_disable(dev);
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drv->remove(dev);
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/* Driver should have reset device. */
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WARN_ON_ONCE(dev->config->get_status(dev));
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/* Acknowledge the device's existence again. */
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virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
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of_node_put(dev->dev.of_node);
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}
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static struct bus_type virtio_bus = {
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.name = "virtio",
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.match = virtio_dev_match,
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.dev_groups = virtio_dev_groups,
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.uevent = virtio_uevent,
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.probe = virtio_dev_probe,
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.remove = virtio_dev_remove,
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};
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int register_virtio_driver(struct virtio_driver *driver)
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{
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/* Catch this early. */
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BUG_ON(driver->feature_table_size && !driver->feature_table);
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driver->driver.bus = &virtio_bus;
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return driver_register(&driver->driver);
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}
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EXPORT_SYMBOL_GPL(register_virtio_driver);
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void unregister_virtio_driver(struct virtio_driver *driver)
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{
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driver_unregister(&driver->driver);
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}
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EXPORT_SYMBOL_GPL(unregister_virtio_driver);
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static int virtio_device_of_init(struct virtio_device *dev)
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{
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struct device_node *np, *pnode = dev_of_node(dev->dev.parent);
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char compat[] = "virtio,deviceXXXXXXXX";
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|
|
int ret, count;
|
||
|
|
|
||
|
|
if (!pnode)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
count = of_get_available_child_count(pnode);
|
||
|
|
if (!count)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
/* There can be only 1 child node */
|
||
|
|
if (WARN_ON(count > 1))
|
||
|
|
return -EINVAL;
|
||
|
|
|
||
|
|
np = of_get_next_available_child(pnode, NULL);
|
||
|
|
if (WARN_ON(!np))
|
||
|
|
return -ENODEV;
|
||
|
|
|
||
|
|
ret = snprintf(compat, sizeof(compat), "virtio,device%x", dev->id.device);
|
||
|
|
BUG_ON(ret >= sizeof(compat));
|
||
|
|
|
||
|
|
/*
|
||
|
|
* On powerpc/pseries virtio devices are PCI devices so PCI
|
||
|
|
* vendor/device ids play the role of the "compatible" property.
|
||
|
|
* Simply don't init of_node in this case.
|
||
|
|
*/
|
||
|
|
if (!of_device_is_compatible(np, compat)) {
|
||
|
|
ret = 0;
|
||
|
|
goto out;
|
||
|
|
}
|
||
|
|
|
||
|
|
dev->dev.of_node = np;
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
out:
|
||
|
|
of_node_put(np);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* 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_alloc(&virtio_index_ida, GFP_KERNEL);
|
||
|
|
if (err < 0)
|
||
|
|
goto out;
|
||
|
|
|
||
|
|
dev->index = err;
|
||
|
|
err = dev_set_name(&dev->dev, "virtio%u", dev->index);
|
||
|
|
if (err)
|
||
|
|
goto out_ida_remove;
|
||
|
|
|
||
|
|
err = virtio_device_of_init(dev);
|
||
|
|
if (err)
|
||
|
|
goto out_ida_remove;
|
||
|
|
|
||
|
|
spin_lock_init(&dev->config_lock);
|
||
|
|
dev->config_enabled = false;
|
||
|
|
dev->config_change_pending = false;
|
||
|
|
|
||
|
|
INIT_LIST_HEAD(&dev->vqs);
|
||
|
|
spin_lock_init(&dev->vqs_list_lock);
|
||
|
|
|
||
|
|
/* We always start by resetting the device, in case a previous
|
||
|
|
* driver messed it up. This also tests that code path a little. */
|
||
|
|
virtio_reset_device(dev);
|
||
|
|
|
||
|
|
/* Acknowledge that we've seen the device. */
|
||
|
|
virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* device_add() causes the bus infrastructure to look for a matching
|
||
|
|
* driver.
|
||
|
|
*/
|
||
|
|
err = device_add(&dev->dev);
|
||
|
|
if (err)
|
||
|
|
goto out_of_node_put;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
out_of_node_put:
|
||
|
|
of_node_put(dev->dev.of_node);
|
||
|
|
out_ida_remove:
|
||
|
|
ida_free(&virtio_index_ida, dev->index);
|
||
|
|
out:
|
||
|
|
virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
|
||
|
|
return err;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(register_virtio_device);
|
||
|
|
|
||
|
|
bool is_virtio_device(struct device *dev)
|
||
|
|
{
|
||
|
|
return dev->bus == &virtio_bus;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(is_virtio_device);
|
||
|
|
|
||
|
|
void unregister_virtio_device(struct virtio_device *dev)
|
||
|
|
{
|
||
|
|
int index = dev->index; /* save for after device release */
|
||
|
|
|
||
|
|
device_unregister(&dev->dev);
|
||
|
|
ida_free(&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. */
|
||
|
|
virtio_reset_device(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 = dev->config->finalize_features(dev);
|
||
|
|
if (ret)
|
||
|
|
goto err;
|
||
|
|
|
||
|
|
ret = virtio_features_ok(dev);
|
||
|
|
if (ret)
|
||
|
|
goto err;
|
||
|
|
|
||
|
|
if (drv->restore) {
|
||
|
|
ret = drv->restore(dev);
|
||
|
|
if (ret)
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* If restore didn't do it, mark device DRIVER_OK ourselves. */
|
||
|
|
if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
|
||
|
|
virtio_device_ready(dev);
|
||
|
|
|
||
|
|
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");
|