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path: root/drivers/xen/xen-pciback/vpci.c
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Diffstat (limited to 'drivers/xen/xen-pciback/vpci.c')
-rw-r--r--drivers/xen/xen-pciback/vpci.c268
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,
+};
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 17:52:56 +0000