diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/xen/xen-pciback/passthrough.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/xen/xen-pciback/passthrough.c b/drivers/xen/xen-pciback/passthrough.c new file mode 100644 index 000000000..66e9b814c --- /dev/null +++ b/drivers/xen/xen-pciback/passthrough.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PCI Backend - Provides restricted access to the real PCI bus topology + * to the frontend + * + * Author: Ryan Wilson <hap9@epoch.ncsc.mil> + */ + +#include <linux/list.h> +#include <linux/pci.h> +#include <linux/mutex.h> +#include "pciback.h" + +struct passthrough_dev_data { + /* Access to dev_list must be protected by lock */ + struct list_head dev_list; + struct mutex lock; +}; + +static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev, + unsigned int domain, + unsigned int bus, + unsigned int devfn) +{ + struct passthrough_dev_data *dev_data = pdev->pci_dev_data; + struct pci_dev_entry *dev_entry; + struct pci_dev *dev = NULL; + + mutex_lock(&dev_data->lock); + + list_for_each_entry(dev_entry, &dev_data->dev_list, list) { + if (domain == (unsigned int)pci_domain_nr(dev_entry->dev->bus) + && bus == (unsigned int)dev_entry->dev->bus->number + && devfn == dev_entry->dev->devfn) { + dev = dev_entry->dev; + break; + } + } + + mutex_unlock(&dev_data->lock); + + return dev; +} + +static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev, + struct pci_dev *dev, + int devid, publish_pci_dev_cb publish_cb) +{ + struct passthrough_dev_data *dev_data = pdev->pci_dev_data; + struct pci_dev_entry *dev_entry; + unsigned int domain, bus, devfn; + int err; + + dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL); + if (!dev_entry) + return -ENOMEM; + dev_entry->dev = dev; + + mutex_lock(&dev_data->lock); + list_add_tail(&dev_entry->list, &dev_data->dev_list); + mutex_unlock(&dev_data->lock); + + /* Publish this device. */ + domain = (unsigned int)pci_domain_nr(dev->bus); + bus = (unsigned int)dev->bus->number; + devfn = dev->devfn; + err = publish_cb(pdev, domain, bus, devfn, devid); + + return err; +} + +static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev, + struct pci_dev *dev, bool lock) +{ + struct passthrough_dev_data *dev_data = pdev->pci_dev_data; + struct pci_dev_entry *dev_entry, *t; + struct pci_dev *found_dev = NULL; + + mutex_lock(&dev_data->lock); + + list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) { + if (dev_entry->dev == dev) { + list_del(&dev_entry->list); + found_dev = dev_entry->dev; + kfree(dev_entry); + } + } + + mutex_unlock(&dev_data->lock); + + if (found_dev) { + if (lock) + device_lock(&found_dev->dev); + pcistub_put_pci_dev(found_dev); + if (lock) + device_unlock(&found_dev->dev); + } +} + +static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev) +{ + struct passthrough_dev_data *dev_data; + + dev_data = kmalloc(sizeof(*dev_data), GFP_KERNEL); + if (!dev_data) + return -ENOMEM; + + mutex_init(&dev_data->lock); + + INIT_LIST_HEAD(&dev_data->dev_list); + + pdev->pci_dev_data = dev_data; + + return 0; +} + +static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev, + publish_pci_root_cb publish_root_cb) +{ + int err = 0; + struct passthrough_dev_data *dev_data = pdev->pci_dev_data; + struct pci_dev_entry *dev_entry, *e; + struct pci_dev *dev; + int found; + unsigned int domain, bus; + + mutex_lock(&dev_data->lock); + + list_for_each_entry(dev_entry, &dev_data->dev_list, list) { + /* Only publish this device as a root if none of its + * parent bridges are exported + */ + found = 0; + dev = dev_entry->dev->bus->self; + for (; !found && dev != NULL; dev = dev->bus->self) { + list_for_each_entry(e, &dev_data->dev_list, list) { + if (dev == e->dev) { + found = 1; + break; + } + } + } + + domain = (unsigned int)pci_domain_nr(dev_entry->dev->bus); + bus = (unsigned int)dev_entry->dev->bus->number; + + if (!found) { + err = publish_root_cb(pdev, domain, bus); + if (err) + break; + } + } + + mutex_unlock(&dev_data->lock); + + return err; +} + +static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev) +{ + struct passthrough_dev_data *dev_data = pdev->pci_dev_data; + struct pci_dev_entry *dev_entry, *t; + + list_for_each_entry_safe(dev_entry, t, &dev_data->dev_list, list) { + struct pci_dev *dev = dev_entry->dev; + list_del(&dev_entry->list); + device_lock(&dev->dev); + pcistub_put_pci_dev(dev); + device_unlock(&dev->dev); + kfree(dev_entry); + } + + kfree(dev_data); + pdev->pci_dev_data = NULL; +} + +static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev, + struct xen_pcibk_device *pdev, + unsigned int *domain, unsigned int *bus, + unsigned int *devfn) +{ + *domain = pci_domain_nr(pcidev->bus); + *bus = pcidev->bus->number; + *devfn = pcidev->devfn; + return 1; +} + +const struct xen_pcibk_backend xen_pcibk_passthrough_backend = { + .name = "passthrough", + .init = __xen_pcibk_init_devices, + .free = __xen_pcibk_release_devices, + .find = __xen_pcibk_get_pcifront_dev, + .publish = __xen_pcibk_publish_pci_roots, + .release = __xen_pcibk_release_pci_dev, + .add = __xen_pcibk_add_pci_dev, + .get = __xen_pcibk_get_pci_dev, +}; |