[people/arne_f/kernel.git] / drivers / xen / xen-pciback / vpci.c

// 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

#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 = -1;
	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
	 * virtual functions.
	 */
	if (!dev->is_virtfn) {
		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 (match_slot(dev, t->dev)) {
				pr_info("vpci: %s: assign to virtual slot %d func %d\n",
					pci_name(dev), slot,
					PCI_FUNC(dev->devfn));
				list_add_tail(&dev_entry->list,
					      &vpci_dev->dev_list[slot]);
				func = PCI_FUNC(dev->devfn);
				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])) {
			pr_info("vpci: %s: assign to virtual slot %d\n",
				pci_name(dev), slot);
			list_add_tail(&dev_entry->list,
				      &vpci_dev->dev_list[slot]);
			func = dev->is_virtfn ? 0 : PCI_FUNC(dev->devfn);
			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 pci_dev *dev = NULL;
	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) {
			dev = entry->dev;
			if (dev && dev->bus->number == pcidev->bus->number
				&& pci_domain_nr(dev->bus) ==
					pci_domain_nr(pcidev->bus)
				&& dev->devfn == pcidev->devfn) {
				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,
};
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
30edc14b KRW	2	/*
	3	* PCI Backend - Provides a Virtual PCI bus (with real devices)
	4	* to the frontend
	5	*
	6	* Author: Ryan Wilson <hap9@epoch.ncsc.mil>
	7	*/
	8
283c0972 JP	9	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
283c0972 JP	10
30edc14b KRW	11	#include <linux/list.h>
	12	#include <linux/slab.h>
	13	#include <linux/pci.h>
74d33ded	14	#include <linux/mutex.h>
30edc14b KRW	15	#include "pciback.h"
	16
	17	#define PCI_SLOT_MAX 32
	18
	19	struct vpci_dev_data {
	20	/* Access to dev_list must be protected by lock */
	21	struct list_head dev_list[PCI_SLOT_MAX];
74d33ded	22	struct mutex lock;
30edc14b KRW	23	};
	24
	25	static inline struct list_head list_first(struct list_head head)
	26	{
	27	return head->next;
	28	}
	29
2ebdc426 KRW	30	static struct pci_dev __xen_pcibk_get_pci_dev(struct xen_pcibk_device pdev,
	31	unsigned int domain,
	32	unsigned int bus,
	33	unsigned int devfn)
30edc14b KRW	34	{
	35	struct pci_dev_entry *entry;
	36	struct pci_dev *dev = NULL;
	37	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
30edc14b KRW	38
	39	if (domain != 0 \|\| bus != 0)
	40	return NULL;
	41
	42	if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
74d33ded	43	mutex_lock(&vpci_dev->lock);
30edc14b KRW	44
	45	list_for_each_entry(entry,
	46	&vpci_dev->dev_list[PCI_SLOT(devfn)],
	47	list) {
	48	if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) {
	49	dev = entry->dev;
	50	break;
	51	}
	52	}
	53
74d33ded	54	mutex_unlock(&vpci_dev->lock);
30edc14b KRW	55	}
	56	return dev;
	57	}
	58
	59	static inline int match_slot(struct pci_dev l, struct pci_dev r)
	60	{
	61	if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus)
	62	&& l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn))
	63	return 1;
	64
	65	return 0;
	66	}
	67
2ebdc426 KRW	68	static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev,
	69	struct pci_dev *dev, int devid,
	70	publish_pci_dev_cb publish_cb)
30edc14b KRW	71	{
	72	int err = 0, slot, func = -1;
	73	struct pci_dev_entry t, dev_entry;
	74	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
30edc14b KRW	75
	76	if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) {
	77	err = -EFAULT;
	78	xenbus_dev_fatal(pdev->xdev, err,
	79	"Can't export bridges on the virtual PCI bus");
	80	goto out;
	81	}
	82
	83	dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
	84	if (!dev_entry) {
	85	err = -ENOMEM;
	86	xenbus_dev_fatal(pdev->xdev, err,
	87	"Error adding entry to virtual PCI bus");
	88	goto out;
	89	}
	90
	91	dev_entry->dev = dev;
	92
74d33ded	93	mutex_lock(&vpci_dev->lock);
30edc14b	94
8a5248fe LE	95	/*
	96	* Keep multi-function devices together on the virtual PCI bus, except
	97	* virtual functions.
	98	*/
	99	if (!dev->is_virtfn) {
	100	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
	101	if (list_empty(&vpci_dev->dev_list[slot]))
	102	continue;
	103
30edc14b KRW	104	t = list_entry(list_first(&vpci_dev->dev_list[slot]),
	105	struct pci_dev_entry, list);
	106
	107	if (match_slot(dev, t->dev)) {
283c0972	108	pr_info("vpci: %s: assign to virtual slot %d func %d\n",
30edc14b KRW	109	pci_name(dev), slot,
	110	PCI_FUNC(dev->devfn));
	111	list_add_tail(&dev_entry->list,
	112	&vpci_dev->dev_list[slot]);
	113	func = PCI_FUNC(dev->devfn);
	114	goto unlock;
	115	}
	116	}
	117	}
	118
	119	/* Assign to a new slot on the virtual PCI bus */
	120	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
	121	if (list_empty(&vpci_dev->dev_list[slot])) {
283c0972 JP	122	pr_info("vpci: %s: assign to virtual slot %d\n",
283c0972 JP	123	pci_name(dev), slot);
30edc14b KRW	124	list_add_tail(&dev_entry->list,
30edc14b KRW	125	&vpci_dev->dev_list[slot]);
8a5248fe	126	func = dev->is_virtfn ? 0 : PCI_FUNC(dev->devfn);
30edc14b KRW	127	goto unlock;
	128	}
	129	}
	130
	131	err = -ENOMEM;
	132	xenbus_dev_fatal(pdev->xdev, err,
	133	"No more space on root virtual PCI bus");
	134
	135	unlock:
74d33ded	136	mutex_unlock(&vpci_dev->lock);
30edc14b KRW	137
	138	/* Publish this device. */
	139	if (!err)
	140	err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
cea37f87 DY	141	else
cea37f87 DY	142	kfree(dev_entry);
30edc14b KRW	143
	144	out:
	145	return err;
	146	}
	147
2ebdc426	148	static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
e8801a74	149	struct pci_dev *dev, bool lock)
30edc14b KRW	150	{
	151	int slot;
	152	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
	153	struct pci_dev *found_dev = NULL;
30edc14b	154
74d33ded	155	mutex_lock(&vpci_dev->lock);
30edc14b KRW	156
30edc14b KRW	157	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
402c5e15 JB	158	struct pci_dev_entry *e;
	159
	160	list_for_each_entry(e, &vpci_dev->dev_list[slot], list) {
30edc14b KRW	161	if (e->dev == dev) {
	162	list_del(&e->list);
	163	found_dev = e->dev;
	164	kfree(e);
	165	goto out;
	166	}
	167	}
	168	}
	169
	170	out:
74d33ded	171	mutex_unlock(&vpci_dev->lock);
30edc14b	172
e8801a74 KRW	173	if (found_dev) {
	174	if (lock)
	175	device_lock(&found_dev->dev);
30edc14b	176	pcistub_put_pci_dev(found_dev);
e8801a74 KRW	177	if (lock)
	178	device_unlock(&found_dev->dev);
	179	}
30edc14b KRW	180	}
30edc14b KRW	181
2ebdc426	182	static int __xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
30edc14b KRW	183	{
	184	int slot;
	185	struct vpci_dev_data *vpci_dev;
	186
	187	vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL);
	188	if (!vpci_dev)
	189	return -ENOMEM;
	190
74d33ded	191	mutex_init(&vpci_dev->lock);
30edc14b KRW	192
	193	for (slot = 0; slot < PCI_SLOT_MAX; slot++)
	194	INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);
	195
	196	pdev->pci_dev_data = vpci_dev;
	197
	198	return 0;
	199	}
	200
2ebdc426 KRW	201	static int __xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
2ebdc426 KRW	202	publish_pci_root_cb publish_cb)
30edc14b KRW	203	{
	204	/* The Virtual PCI bus has only one root */
	205	return publish_cb(pdev, 0, 0);
	206	}
	207
2ebdc426	208	static void __xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
30edc14b KRW	209	{
	210	int slot;
	211	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
	212
	213	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
	214	struct pci_dev_entry e, tmp;
	215	list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
	216	list) {
e8801a74	217	struct pci_dev *dev = e->dev;
30edc14b	218	list_del(&e->list);
e8801a74 KRW	219	device_lock(&dev->dev);
	220	pcistub_put_pci_dev(dev);
	221	device_unlock(&dev->dev);
30edc14b KRW	222	kfree(e);
	223	}
	224	}
	225
	226	kfree(vpci_dev);
	227	pdev->pci_dev_data = NULL;
	228	}
	229
2ebdc426 KRW	230	static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
	231	struct xen_pcibk_device *pdev,
	232	unsigned int domain, unsigned int bus,
	233	unsigned int *devfn)
30edc14b KRW	234	{
	235	struct pci_dev_entry *entry;
	236	struct pci_dev *dev = NULL;
	237	struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
30edc14b KRW	238	int found = 0, slot;
30edc14b KRW	239
74d33ded	240	mutex_lock(&vpci_dev->lock);
30edc14b KRW	241	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
	242	list_for_each_entry(entry,
	243	&vpci_dev->dev_list[slot],
	244	list) {
	245	dev = entry->dev;
	246	if (dev && dev->bus->number == pcidev->bus->number
	247	&& pci_domain_nr(dev->bus) ==
	248	pci_domain_nr(pcidev->bus)
	249	&& dev->devfn == pcidev->devfn) {
	250	found = 1;
	251	*domain = 0;
	252	*bus = 0;
	253	*devfn = PCI_DEVFN(slot,
	254	PCI_FUNC(pcidev->devfn));
	255	}
	256	}
	257	}
e1db4cef	258	mutex_unlock(&vpci_dev->lock);
30edc14b KRW	259	return found;
30edc14b KRW	260	}
2ebdc426	261
402c5e15	262	const struct xen_pcibk_backend xen_pcibk_vpci_backend = {
2ebdc426 KRW	263	.name = "vpci",
	264	.init = __xen_pcibk_init_devices,
	265	.free = __xen_pcibk_release_devices,
	266	.find = __xen_pcibk_get_pcifront_dev,
	267	.publish = __xen_pcibk_publish_pci_roots,
	268	.release = __xen_pcibk_release_pci_dev,
	269	.add = __xen_pcibk_add_pci_dev,
	270	.get = __xen_pcibk_get_pci_dev,
	271	};