diff options
Diffstat (limited to 'drivers/virtio/virtio.c')
| -rw-r--r-- | drivers/virtio/virtio.c | 601 |
1 files changed, 543 insertions, 58 deletions
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index ee59b74768d9..5bdc6b82b30b 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -1,8 +1,12 @@ +// SPDX-License-Identifier: GPL-2.0-only #include <linux/virtio.h> #include <linux/spinlock.h> #include <linux/virtio_config.h> +#include <linux/virtio_anchor.h> #include <linux/module.h> #include <linux/idr.h> +#include <linux/of.h> +#include <uapi/linux/virtio_ids.h> /* Unique numbering for virtio devices. */ static DEFINE_IDA(virtio_index_ida); @@ -11,27 +15,35 @@ 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); + 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 sprintf(buf, "0x%04x\n", dev->id.vendor); + 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 sprintf(buf, "0x%08x\n", dev->config->get_status(dev)); + 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 sprintf(buf, "virtio:d%08Xv%08X\n", + 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) { @@ -41,20 +53,23 @@ static ssize_t features_show(struct device *_d, /* We actually represent this as a bitstring, as it could be * arbitrary length in future. */ - for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++) - len += sprintf(buf+len, "%c", - test_bit(i, dev->features) ? '1' : '0'); - len += sprintf(buf+len, "\n"); + for (i = 0; i < VIRTIO_FEATURES_BITS; 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 struct device_attribute virtio_dev_attrs[] = { - __ATTR_RO(device), - __ATTR_RO(vendor), - __ATTR_RO(status), - __ATTR_RO(modalias), - __ATTR_RO(features), - __ATTR_NULL +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) @@ -67,7 +82,7 @@ static inline int virtio_id_match(const struct virtio_device *dev, /* 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) +static int virtio_dev_match(struct device *_dv, const struct device_driver *_dr) { unsigned int i; struct virtio_device *dev = dev_to_virtio(_dv); @@ -80,19 +95,14 @@ static int virtio_dev_match(struct device *_dv, struct device_driver *_dr) return 0; } -static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env) +static int virtio_uevent(const struct device *_dv, struct kobj_uevent_env *env) { - struct virtio_device *dev = dev_to_virtio(_dv); + 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); } -static void add_status(struct virtio_device *dev, unsigned status) -{ - dev->config->set_status(dev, dev->config->get_status(dev) | status); -} - void virtio_check_driver_offered_feature(const struct virtio_device *vdev, unsigned int fbit) { @@ -102,83 +112,350 @@ void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 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_core_enabled || dev->config_driver_disabled) + dev->config_change_pending = true; + else if (drv && drv->config_changed) { + drv->config_changed(dev); + dev->config_change_pending = false; + } +} + +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); + +/** + * virtio_config_driver_disable - disable config change reporting by drivers + * @dev: the device to disable + * + * This is only allowed to be called by a driver and disabling can't + * be nested. + */ +void virtio_config_driver_disable(struct virtio_device *dev) +{ + spin_lock_irq(&dev->config_lock); + dev->config_driver_disabled = true; + spin_unlock_irq(&dev->config_lock); +} +EXPORT_SYMBOL_GPL(virtio_config_driver_disable); + +/** + * virtio_config_driver_enable - enable config change reporting by drivers + * @dev: the device to enable + * + * This is only allowed to be called by a driver and enabling can't + * be nested. + */ +void virtio_config_driver_enable(struct virtio_device *dev) +{ + spin_lock_irq(&dev->config_lock); + dev->config_driver_disabled = false; + if (dev->config_change_pending) + __virtio_config_changed(dev); + spin_unlock_irq(&dev->config_lock); +} +EXPORT_SYMBOL_GPL(virtio_config_driver_enable); + +static void virtio_config_core_disable(struct virtio_device *dev) +{ + spin_lock_irq(&dev->config_lock); + dev->config_core_enabled = false; + spin_unlock_irq(&dev->config_lock); +} + +static void virtio_config_core_enable(struct virtio_device *dev) +{ + spin_lock_irq(&dev->config_lock); + dev->config_core_enabled = true; + if (dev->config_change_pending) + __virtio_config_changed(dev); + 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); - u32 device_features; + u64 device_features[VIRTIO_FEATURES_U64S]; + u64 driver_features[VIRTIO_FEATURES_U64S]; + u64 driver_features_legacy; /* We have a driver! */ - add_status(dev, VIRTIO_CONFIG_S_DRIVER); + virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER); /* Figure out what features the device supports. */ - device_features = dev->config->get_features(dev); + virtio_get_features(dev, device_features); - /* Features supported by both device and driver into dev->features. */ - memset(dev->features, 0, sizeof(dev->features)); + /* Figure out what features the driver supports. */ + virtio_features_zero(driver_features); for (i = 0; i < drv->feature_table_size; i++) { unsigned int f = drv->feature_table[i]; - BUG_ON(f >= 32); - if (device_features & (1 << f)) - set_bit(f, dev->features); + if (!WARN_ON_ONCE(f >= VIRTIO_FEATURES_BITS)) + virtio_features_set_bit(driver_features, 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]; + if (!WARN_ON_ONCE(f >= 64)) + driver_features_legacy |= (1ULL << f); + } + } else { + driver_features_legacy = driver_features[0]; + } + + if (virtio_features_test_bit(device_features, VIRTIO_F_VERSION_1)) { + for (i = 0; i < VIRTIO_FEATURES_U64S; ++i) + dev->features_array[i] = driver_features[i] & + device_features[i]; + } else { + virtio_features_from_u64(dev->features_array, + driver_features_legacy & + device_features[0]); + } + + /* When debugging, user may filter some features by hand. */ + virtio_debug_device_filter_features(dev); + /* Transport features always preserved to pass to finalize_features. */ for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) - if (device_features & (1 << i)) - set_bit(i, dev->features); + if (virtio_features_test_bit(device_features, i)) + __virtio_set_bit(dev, i); + + err = dev->config->finalize_features(dev); + if (err) + goto err; + + if (drv->validate) { + u64 features[VIRTIO_FEATURES_U64S]; + + virtio_features_copy(features, dev->features_array); + err = drv->validate(dev); + if (err) + goto err; + + /* Did validation change any features? Then write them again. */ + if (!virtio_features_equal(features, dev->features_array)) { + err = dev->config->finalize_features(dev); + if (err) + goto err; + } + } - dev->config->finalize_features(dev); + err = virtio_features_ok(dev); + if (err) + goto err; err = drv->probe(dev); if (err) - add_status(dev, VIRTIO_CONFIG_S_FAILED); - else { - add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); - if (drv->scan) - drv->scan(dev); - } + 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_core_enable(dev); + return 0; + +err: + virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); return err; + } -static int virtio_dev_remove(struct device *_d) +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_core_disable(dev); + drv->remove(dev); /* Driver should have reset device. */ WARN_ON_ONCE(dev->config->get_status(dev)); /* Acknowledge the device's existence again. */ - add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); - return 0; + virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); + + of_node_put(dev->dev.of_node); +} + +/* + * virtio_irq_get_affinity - get IRQ affinity mask for device + * @_d: ptr to dev structure + * @irq_vec: interrupt vector number + * + * Return the CPU affinity mask for @_d and @irq_vec. + */ +static const struct cpumask *virtio_irq_get_affinity(struct device *_d, + unsigned int irq_vec) +{ + struct virtio_device *dev = dev_to_virtio(_d); + + if (!dev->config->get_vq_affinity) + return NULL; + + return dev->config->get_vq_affinity(dev, irq_vec); +} + +static void virtio_dev_shutdown(struct device *_d) +{ + struct virtio_device *dev = dev_to_virtio(_d); + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + + /* + * Stop accesses to or from the device. + * We only need to do it if there's a driver - no accesses otherwise. + */ + if (!drv) + return; + + /* If the driver has its own shutdown method, use that. */ + if (drv->shutdown) { + drv->shutdown(dev); + return; + } + + /* + * Some devices get wedged if you kick them after they are + * reset. Mark all vqs as broken to make sure we don't. + */ + virtio_break_device(dev); + /* + * Guarantee that any callback will see vq->broken as true. + */ + virtio_synchronize_cbs(dev); + /* + * As IOMMUs are reset on shutdown, this will block device access to memory. + * Some devices get wedged if this happens, so reset to make sure it does not. + */ + dev->config->reset(dev); } -static struct bus_type virtio_bus = { +static const struct bus_type virtio_bus = { .name = "virtio", .match = virtio_dev_match, - .dev_attrs = virtio_dev_attrs, + .dev_groups = virtio_dev_groups, .uevent = virtio_uevent, .probe = virtio_dev_probe, .remove = virtio_dev_remove, + .irq_get_affinity = virtio_irq_get_affinity, + .shutdown = virtio_dev_shutdown, }; -int register_virtio_driver(struct virtio_driver *driver) +int __register_virtio_driver(struct virtio_driver *driver, struct module *owner) { /* Catch this early. */ BUG_ON(driver->feature_table_size && !driver->feature_table); driver->driver.bus = &virtio_bus; + driver->driver.owner = owner; + return driver_register(&driver->driver); } -EXPORT_SYMBOL_GPL(register_virtio_driver); +EXPORT_SYMBOL_GPL(__register_virtio_driver); void unregister_virtio_driver(struct virtio_driver *driver) { @@ -186,60 +463,268 @@ void unregister_virtio_driver(struct virtio_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 success, -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); + err = ida_alloc(&virtio_index_ida, GFP_KERNEL); if (err < 0) goto out; dev->index = err; - dev_set_name(&dev->dev, "virtio%u", dev->index); + 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_driver_disabled = false; + dev->config_core_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. */ - dev->config->reset(dev); + virtio_reset_device(dev); /* Acknowledge that we've seen the device. */ - add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); + virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); - INIT_LIST_HEAD(&dev->vqs); + virtio_debug_device_init(dev); - /* device_register() causes the bus infrastructure to look for a - * matching driver. */ - err = device_register(&dev->dev); -out: + /* + * device_add() causes the bus infrastructure to look for a matching + * driver. + */ + err = device_add(&dev->dev); if (err) - add_status(dev, VIRTIO_CONFIG_S_FAILED); + 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_simple_remove(&virtio_index_ida, index); + virtio_debug_device_exit(dev); + ida_free(&virtio_index_ida, index); } EXPORT_SYMBOL_GPL(unregister_virtio_device); +static int virtio_device_restore_priv(struct virtio_device *dev, bool restore) +{ + 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 (restore) { + if (drv->restore) { + ret = drv->restore(dev); + if (ret) + goto err; + } + } else { + ret = drv->reset_done(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_core_enable(dev); + + return 0; + +err: + virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED); + return ret; +} + +#ifdef CONFIG_PM_SLEEP +int virtio_device_freeze(struct virtio_device *dev) +{ + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + int ret; + + virtio_config_core_disable(dev); + + dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED; + + if (drv && drv->freeze) { + ret = drv->freeze(dev); + if (ret) { + virtio_config_core_enable(dev); + return ret; + } + } + + return 0; +} +EXPORT_SYMBOL_GPL(virtio_device_freeze); + +int virtio_device_restore(struct virtio_device *dev) +{ + return virtio_device_restore_priv(dev, true); +} +EXPORT_SYMBOL_GPL(virtio_device_restore); +#endif + +int virtio_device_reset_prepare(struct virtio_device *dev) +{ + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + int ret; + + if (!drv || !drv->reset_prepare) + return -EOPNOTSUPP; + + virtio_config_core_disable(dev); + + dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED; + + ret = drv->reset_prepare(dev); + if (ret) { + virtio_config_core_enable(dev); + return ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(virtio_device_reset_prepare); + +int virtio_device_reset_done(struct virtio_device *dev) +{ + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); + + if (!drv || !drv->reset_done) + return -EOPNOTSUPP; + + return virtio_device_restore_priv(dev, false); +} +EXPORT_SYMBOL_GPL(virtio_device_reset_done); + static int virtio_init(void) { + BUILD_BUG_ON(offsetof(struct virtio_device, features) != + offsetof(struct virtio_device, features_array[0])); + if (bus_register(&virtio_bus) != 0) panic("virtio bus registration failed"); + virtio_debug_init(); return 0; } static void __exit virtio_exit(void) { + virtio_debug_exit(); bus_unregister(&virtio_bus); + ida_destroy(&virtio_index_ida); } core_initcall(virtio_init); module_exit(virtio_exit); +MODULE_DESCRIPTION("Virtio core interface"); MODULE_LICENSE("GPL"); |