From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/virtio/virtio.c | 571 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 571 insertions(+) create mode 100644 drivers/virtio/virtio.c (limited to 'drivers/virtio/virtio.c') diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c new file mode 100644 index 0000000000..3893dc29eb --- /dev/null +++ b/drivers/virtio/virtio.c @@ -0,0 +1,571 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include +#include +#include +#include + +/* 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 sysfs_emit(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 sysfs_emit(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 sysfs_emit(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 sysfs_emit(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 += sysfs_emit_at(buf, len, "%c", + __virtio_test_bit(dev, i) ? '1' : '0'); + len += sysfs_emit_at(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(const struct device *_dv, struct kobj_uevent_env *env) +{ + const 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); + +static void virtio_config_disable(struct virtio_device *dev) +{ + spin_lock_irq(&dev->config_lock); + dev->config_enabled = false; + spin_unlock_irq(&dev->config_lock); +} + +static 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); +} + +void virtio_add_status(struct virtio_device *dev, unsigned int status) +{ + might_sleep(); + dev->config->set_status(dev, dev->config->get_status(dev) | status); +} +EXPORT_SYMBOL_GPL(virtio_add_status); + +/* Do some validation, then set FEATURES_OK */ +static int virtio_features_ok(struct virtio_device *dev) +{ + unsigned int status; + + might_sleep(); + + if (virtio_check_mem_acc_cb(dev)) { + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_VERSION_1\n"); + return -ENODEV; + } + + if (!virtio_has_feature(dev, VIRTIO_F_ACCESS_PLATFORM)) { + dev_warn(&dev->dev, + "device must provide VIRTIO_F_ACCESS_PLATFORM\n"); + return -ENODEV; + } + } + + 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; +} + +/** + * virtio_reset_device - quiesce device for removal + * @dev: the device to reset + * + * Prevents device from sending interrupts and accessing memory. + * + * Generally used for cleanup during driver / device removal. + * + * Once this has been invoked, caller must ensure that + * virtqueue_notify / virtqueue_kick are not in progress. + * + * Note: this guarantees that vq callbacks are not in progress, however caller + * is responsible for preventing access from other contexts, such as a system + * call/workqueue/bh. Invoking virtio_break_device then flushing any such + * contexts is one way to handle that. + * */ +void virtio_reset_device(struct virtio_device *dev) +{ +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION + /* + * The below virtio_synchronize_cbs() guarantees that any + * interrupt for this line arriving after + * virtio_synchronize_vqs() has completed is guaranteed to see + * vq->broken as true. + */ + virtio_break_device(dev); + virtio_synchronize_cbs(dev); +#endif + + dev->config->reset(dev); +} +EXPORT_SYMBOL_GPL(virtio_reset_device); + +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); + + err = dev->config->finalize_features(dev); + if (err) + goto err; + + if (drv->validate) { + u64 features = dev->features; + + err = drv->validate(dev); + if (err) + goto err; + + /* Did validation change any features? Then write them again. */ + if (features != dev->features) { + err = dev->config->finalize_features(dev); + if (err) + goto err; + } + } + + err = virtio_features_ok(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 void 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); + + of_node_put(dev->dev.of_node); +} + +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); + +static int virtio_device_of_init(struct virtio_device *dev) +{ + struct device_node *np, *pnode = dev_of_node(dev->dev.parent); + char compat[] = "virtio,deviceXXXXXXXX"; + 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"); -- cgit v1.2.3