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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/xen/xen-pciback/vpci.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/xen/xen-pciback/vpci.c')
-rw-r--r-- | drivers/xen/xen-pciback/vpci.c | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/drivers/xen/xen-pciback/vpci.c b/drivers/xen/xen-pciback/vpci.c new file mode 100644 index 000000000..cc7450f2b --- /dev/null +++ b/drivers/xen/xen-pciback/vpci.c @@ -0,0 +1,268 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PCI Backend - Provides a Virtual PCI bus (with real devices) + * to the frontend + * + * Author: Ryan Wilson <hap9@epoch.ncsc.mil> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#define dev_fmt pr_fmt + +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/pci.h> +#include <linux/mutex.h> +#include "pciback.h" + +#define PCI_SLOT_MAX 32 + +struct vpci_dev_data { + /* Access to dev_list must be protected by lock */ + struct list_head dev_list[PCI_SLOT_MAX]; + struct mutex lock; +}; + +static inline struct list_head *list_first(struct list_head *head) +{ + return head->next; +} + +static struct pci_dev *__xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev, + unsigned int domain, + unsigned int bus, + unsigned int devfn) +{ + struct pci_dev_entry *entry; + struct pci_dev *dev = NULL; + struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; + + if (domain != 0 || bus != 0) + return NULL; + + if (PCI_SLOT(devfn) < PCI_SLOT_MAX) { + mutex_lock(&vpci_dev->lock); + + list_for_each_entry(entry, + &vpci_dev->dev_list[PCI_SLOT(devfn)], + list) { + if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) { + dev = entry->dev; + break; + } + } + + mutex_unlock(&vpci_dev->lock); + } + return dev; +} + +static inline int match_slot(struct pci_dev *l, struct pci_dev *r) +{ + if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus) + && l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn)) + return 1; + + return 0; +} + +static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev, + struct pci_dev *dev, int devid, + publish_pci_dev_cb publish_cb) +{ + int err = 0, slot, func = PCI_FUNC(dev->devfn); + struct pci_dev_entry *t, *dev_entry; + struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; + + if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) { + err = -EFAULT; + xenbus_dev_fatal(pdev->xdev, err, + "Can't export bridges on the virtual PCI bus"); + goto out; + } + + dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL); + if (!dev_entry) { + err = -ENOMEM; + xenbus_dev_fatal(pdev->xdev, err, + "Error adding entry to virtual PCI bus"); + goto out; + } + + dev_entry->dev = dev; + + mutex_lock(&vpci_dev->lock); + + /* + * Keep multi-function devices together on the virtual PCI bus, except + * that we want to keep virtual functions at func 0 on their own. They + * aren't multi-function devices and hence their presence at func 0 + * may cause guests to not scan the other functions. + */ + if (!dev->is_virtfn || func) { + for (slot = 0; slot < PCI_SLOT_MAX; slot++) { + if (list_empty(&vpci_dev->dev_list[slot])) + continue; + + t = list_entry(list_first(&vpci_dev->dev_list[slot]), + struct pci_dev_entry, list); + if (t->dev->is_virtfn && !PCI_FUNC(t->dev->devfn)) + continue; + + if (match_slot(dev, t->dev)) { + dev_info(&dev->dev, "vpci: assign to virtual slot %d func %d\n", + slot, func); + list_add_tail(&dev_entry->list, + &vpci_dev->dev_list[slot]); + goto unlock; + } + } + } + + /* Assign to a new slot on the virtual PCI bus */ + for (slot = 0; slot < PCI_SLOT_MAX; slot++) { + if (list_empty(&vpci_dev->dev_list[slot])) { + dev_info(&dev->dev, "vpci: assign to virtual slot %d\n", + slot); + list_add_tail(&dev_entry->list, + &vpci_dev->dev_list[slot]); + goto unlock; + } + } + + err = -ENOMEM; + xenbus_dev_fatal(pdev->xdev, err, + "No more space on root virtual PCI bus"); + +unlock: + mutex_unlock(&vpci_dev->lock); + + /* Publish this device. */ + if (!err) + err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid); + else + kfree(dev_entry); + +out: + return err; +} + +static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev, + struct pci_dev *dev, bool lock) +{ + int slot; + struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; + struct pci_dev *found_dev = NULL; + + mutex_lock(&vpci_dev->lock); + + for (slot = 0; slot < PCI_SLOT_MAX; slot++) { + struct pci_dev_entry *e; + + list_for_each_entry(e, &vpci_dev->dev_list[slot], list) { + if (e->dev == dev) { + list_del(&e->list); + found_dev = e->dev; + kfree(e); + goto out; + } + } + } + +out: + mutex_unlock(&vpci_dev->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) +{ + int slot; + struct vpci_dev_data *vpci_dev; + + vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL); + if (!vpci_dev) + return -ENOMEM; + + mutex_init(&vpci_dev->lock); + + for (slot = 0; slot < PCI_SLOT_MAX; slot++) + INIT_LIST_HEAD(&vpci_dev->dev_list[slot]); + + pdev->pci_dev_data = vpci_dev; + + return 0; +} + +static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev, + publish_pci_root_cb publish_cb) +{ + /* The Virtual PCI bus has only one root */ + return publish_cb(pdev, 0, 0); +} + +static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev) +{ + int slot; + struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; + + for (slot = 0; slot < PCI_SLOT_MAX; slot++) { + struct pci_dev_entry *e, *tmp; + list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot], + list) { + struct pci_dev *dev = e->dev; + list_del(&e->list); + device_lock(&dev->dev); + pcistub_put_pci_dev(dev); + device_unlock(&dev->dev); + kfree(e); + } + } + + kfree(vpci_dev); + 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) +{ + struct pci_dev_entry *entry; + struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; + int found = 0, slot; + + mutex_lock(&vpci_dev->lock); + for (slot = 0; slot < PCI_SLOT_MAX; slot++) { + list_for_each_entry(entry, + &vpci_dev->dev_list[slot], + list) { + if (entry->dev == pcidev) { + found = 1; + *domain = 0; + *bus = 0; + *devfn = PCI_DEVFN(slot, + PCI_FUNC(pcidev->devfn)); + } + } + } + mutex_unlock(&vpci_dev->lock); + return found; +} + +const struct xen_pcibk_backend xen_pcibk_vpci_backend = { + .name = "vpci", + .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, +}; |