[mirror_ubuntu-artful-kernel.git] / drivers / s390 / kvm / kvm_virtio.c

/*
 * kvm_virtio.c - virtio for kvm on s390
 *
 * Copyright IBM Corp. 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 *
 *    Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
 */

#include <linux/kernel_stat.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/err.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/slab.h>
#include <linux/virtio_console.h>
#include <linux/interrupt.h>
#include <linux/virtio_ring.h>
#include <linux/export.h>
#include <linux/pfn.h>
#include <asm/io.h>
#include <asm/kvm_para.h>
#include <asm/kvm_virtio.h>
#include <asm/setup.h>
#include <asm/irq.h>

#define VIRTIO_SUBCODE_64 0x0D00

/*
 * The pointer to our (page) of device descriptions.
 */
static void *kvm_devices;
static struct work_struct hotplug_work;

struct kvm_device {
	struct virtio_device vdev;
	struct kvm_device_desc *desc;
};

#define to_kvmdev(vd) container_of(vd, struct kvm_device, vdev)

/*
 * memory layout:
 * - kvm_device_descriptor
 *        struct kvm_device_desc
 * - configuration
 *        struct kvm_vqconfig
 * - feature bits
 * - config space
 */
static struct kvm_vqconfig *kvm_vq_config(const struct kvm_device_desc *desc)
{
	return (struct kvm_vqconfig *)(desc + 1);
}

static u8 *kvm_vq_features(const struct kvm_device_desc *desc)
{
	return (u8 *)(kvm_vq_config(desc) + desc->num_vq);
}

static u8 *kvm_vq_configspace(const struct kvm_device_desc *desc)
{
	return kvm_vq_features(desc) + desc->feature_len * 2;
}

/*
 * The total size of the config page used by this device (incl. desc)
 */
static unsigned desc_size(const struct kvm_device_desc *desc)
{
	return sizeof(*desc)
		+ desc->num_vq * sizeof(struct kvm_vqconfig)
		+ desc->feature_len * 2
		+ desc->config_len;
}

/* This gets the device's feature bits. */
static u32 kvm_get_features(struct virtio_device *vdev)
{
	unsigned int i;
	u32 features = 0;
	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	u8 *in_features = kvm_vq_features(desc);

	for (i = 0; i < min(desc->feature_len * 8, 32); i++)
		if (in_features[i / 8] & (1 << (i % 8)))
			features |= (1 << i);
	return features;
}

static void kvm_finalize_features(struct virtio_device *vdev)
{
	unsigned int i, bits;
	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	/* Second half of bitmap is features we accept. */
	u8 *out_features = kvm_vq_features(desc) + desc->feature_len;

	/* Give virtio_ring a chance to accept features. */
	vring_transport_features(vdev);

	memset(out_features, 0, desc->feature_len);
	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
	for (i = 0; i < bits; i++) {
		if (test_bit(i, vdev->features))
			out_features[i / 8] |= (1 << (i % 8));
	}
}

/*
 * Reading and writing elements in config space
 */
static void kvm_get(struct virtio_device *vdev, unsigned int offset,
		   void *buf, unsigned len)
{
	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;

	BUG_ON(offset + len > desc->config_len);
	memcpy(buf, kvm_vq_configspace(desc) + offset, len);
}

static void kvm_set(struct virtio_device *vdev, unsigned int offset,
		   const void *buf, unsigned len)
{
	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;

	BUG_ON(offset + len > desc->config_len);
	memcpy(kvm_vq_configspace(desc) + offset, buf, len);
}

/*
 * The operations to get and set the status word just access
 * the status field of the device descriptor. set_status will also
 * make a hypercall to the host, to tell about status changes
 */
static u8 kvm_get_status(struct virtio_device *vdev)
{
	return to_kvmdev(vdev)->desc->status;
}

static void kvm_set_status(struct virtio_device *vdev, u8 status)
{
	BUG_ON(!status);
	to_kvmdev(vdev)->desc->status = status;
	kvm_hypercall1(KVM_S390_VIRTIO_SET_STATUS,
		       (unsigned long) to_kvmdev(vdev)->desc);
}

/*
 * To reset the device, we use the KVM_VIRTIO_RESET hypercall, using the
 * descriptor address. The Host will zero the status and all the
 * features.
 */
static void kvm_reset(struct virtio_device *vdev)
{
	kvm_hypercall1(KVM_S390_VIRTIO_RESET,
		       (unsigned long) to_kvmdev(vdev)->desc);
}

/*
 * When the virtio_ring code wants to notify the Host, it calls us here and we
 * make a hypercall.  We hand the address  of the virtqueue so the Host
 * knows which virtqueue we're talking about.
 */
static void kvm_notify(struct virtqueue *vq)
{
	struct kvm_vqconfig *config = vq->priv;

	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, config->address);
}

/*
 * This routine finds the first virtqueue described in the configuration of
 * this device and sets it up.
 */
static struct virtqueue *kvm_find_vq(struct virtio_device *vdev,
				     unsigned index,
				     void (*callback)(struct virtqueue *vq),
				     const char *name)
{
	struct kvm_device *kdev = to_kvmdev(vdev);
	struct kvm_vqconfig *config;
	struct virtqueue *vq;
	int err;

	if (index >= kdev->desc->num_vq)
		return ERR_PTR(-ENOENT);

	config = kvm_vq_config(kdev->desc)+index;

	err = vmem_add_mapping(config->address,
			       vring_size(config->num,
					  KVM_S390_VIRTIO_RING_ALIGN));
	if (err)
		goto out;

	vq = vring_new_virtqueue(config->num, KVM_S390_VIRTIO_RING_ALIGN,
				 vdev, (void *) config->address,
				 kvm_notify, callback, name);
	if (!vq) {
		err = -ENOMEM;
		goto unmap;
	}

	/*
	 * register a callback token
	 * The host will sent this via the external interrupt parameter
	 */
	config->token = (u64) vq;

	vq->priv = config;
	return vq;
unmap:
	vmem_remove_mapping(config->address,
			    vring_size(config->num,
				       KVM_S390_VIRTIO_RING_ALIGN));
out:
	return ERR_PTR(err);
}

static void kvm_del_vq(struct virtqueue *vq)
{
	struct kvm_vqconfig *config = vq->priv;

	vring_del_virtqueue(vq);
	vmem_remove_mapping(config->address,
			    vring_size(config->num,
				       KVM_S390_VIRTIO_RING_ALIGN));
}

static void kvm_del_vqs(struct virtio_device *vdev)
{
	struct virtqueue *vq, *n;

	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
		kvm_del_vq(vq);
}

static int kvm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
			struct virtqueue *vqs[],
			vq_callback_t *callbacks[],
			const char *names[])
{
	struct kvm_device *kdev = to_kvmdev(vdev);
	int i;

	/* We must have this many virtqueues. */
	if (nvqs > kdev->desc->num_vq)
		return -ENOENT;

	for (i = 0; i < nvqs; ++i) {
		vqs[i] = kvm_find_vq(vdev, i, callbacks[i], names[i]);
		if (IS_ERR(vqs[i]))
			goto error;
	}
	return 0;

error:
	kvm_del_vqs(vdev);
	return PTR_ERR(vqs[i]);
}

/*
 * The config ops structure as defined by virtio config
 */
static struct virtio_config_ops kvm_vq_configspace_ops = {
	.get_features = kvm_get_features,
	.finalize_features = kvm_finalize_features,
	.get = kvm_get,
	.set = kvm_set,
	.get_status = kvm_get_status,
	.set_status = kvm_set_status,
	.reset = kvm_reset,
	.find_vqs = kvm_find_vqs,
	.del_vqs = kvm_del_vqs,
};

/*
 * The root device for the kvm virtio devices.
 * This makes them appear as /sys/devices/kvm_s390/0,1,2 not /sys/devices/0,1,2.
 */
static struct device *kvm_root;

/*
 * adds a new device and register it with virtio
 * appropriate drivers are loaded by the device model
 */
static void add_kvm_device(struct kvm_device_desc *d, unsigned int offset)
{
	struct kvm_device *kdev;

	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
	if (!kdev) {
		printk(KERN_EMERG "Cannot allocate kvm dev %u type %u\n",
		       offset, d->type);
		return;
	}

	kdev->vdev.dev.parent = kvm_root;
	kdev->vdev.id.device = d->type;
	kdev->vdev.config = &kvm_vq_configspace_ops;
	kdev->desc = d;

	if (register_virtio_device(&kdev->vdev) != 0) {
		printk(KERN_ERR "Failed to register kvm device %u type %u\n",
		       offset, d->type);
		kfree(kdev);
	}
}

/*
 * scan_devices() simply iterates through the device page.
 * The type 0 is reserved to mean "end of devices".
 */
static void scan_devices(void)
{
	unsigned int i;
	struct kvm_device_desc *d;

	for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
		d = kvm_devices + i;

		if (d->type == 0)
			break;

		add_kvm_device(d, i);
	}
}

/*
 * match for a kvm device with a specific desc pointer
 */
static int match_desc(struct device *dev, void *data)
{
	struct virtio_device *vdev = dev_to_virtio(dev);
	struct kvm_device *kdev = to_kvmdev(vdev);

	return kdev->desc == data;
}

/*
 * hotplug_device tries to find changes in the device page.
 */
static void hotplug_devices(struct work_struct *dummy)
{
	unsigned int i;
	struct kvm_device_desc *d;
	struct device *dev;

	for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
		d = kvm_devices + i;

		/* end of list */
		if (d->type == 0)
			break;

		/* device already exists */
		dev = device_find_child(kvm_root, d, match_desc);
		if (dev) {
			/* XXX check for hotplug remove */
			put_device(dev);
			continue;
		}

		/* new device */
		printk(KERN_INFO "Adding new virtio device %p\n", d);
		add_kvm_device(d, i);
	}
}

/*
 * we emulate the request_irq behaviour on top of s390 extints
 */
static void kvm_extint_handler(unsigned int ext_int_code,
			       unsigned int param32, unsigned long param64)
{
	struct virtqueue *vq;
	u16 subcode;
	u32 param;

	subcode = ext_int_code >> 16;
	if ((subcode & 0xff00) != VIRTIO_SUBCODE_64)
		return;
	kstat_cpu(smp_processor_id()).irqs[EXTINT_VRT]++;

	/* The LSB might be overloaded, we have to mask it */
	vq = (struct virtqueue *)(param64 & ~1UL);

	/* We use ext_params to decide what this interrupt means */
	param = param32 & VIRTIO_PARAM_MASK;

	switch (param) {
	case VIRTIO_PARAM_CONFIG_CHANGED:
	{
		struct virtio_driver *drv;
		drv = container_of(vq->vdev->dev.driver,
				   struct virtio_driver, driver);
		if (drv->config_changed)
			drv->config_changed(vq->vdev);

		break;
	}
	case VIRTIO_PARAM_DEV_ADD:
		schedule_work(&hotplug_work);
		break;
	case VIRTIO_PARAM_VRING_INTERRUPT:
	default:
		vring_interrupt(0, vq);
		break;
	}
}

/*
 * Init function for virtio
 * devices are in a single page above top of "normal" mem
 */
static int __init kvm_devices_init(void)
{
	int rc;

	if (!MACHINE_IS_KVM)
		return -ENODEV;

	kvm_root = root_device_register("kvm_s390");
	if (IS_ERR(kvm_root)) {
		rc = PTR_ERR(kvm_root);
		printk(KERN_ERR "Could not register kvm_s390 root device");
		return rc;
	}

	rc = vmem_add_mapping(real_memory_size, PAGE_SIZE);
	if (rc) {
		root_device_unregister(kvm_root);
		return rc;
	}

	kvm_devices = (void *) real_memory_size;

	INIT_WORK(&hotplug_work, hotplug_devices);

	service_subclass_irq_register();
	register_external_interrupt(0x2603, kvm_extint_handler);

	scan_devices();
	return 0;
}

/* code for early console output with virtio_console */
static __init int early_put_chars(u32 vtermno, const char *buf, int count)
{
	char scratch[17];
	unsigned int len = count;

	if (len > sizeof(scratch) - 1)
		len = sizeof(scratch) - 1;
	scratch[len] = '\0';
	memcpy(scratch, buf, len);
	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, __pa(scratch));
	return len;
}

static int __init s390_virtio_console_init(void)
{
	if (!MACHINE_IS_KVM)
		return -ENODEV;
	return virtio_cons_early_init(early_put_chars);
}
console_initcall(s390_virtio_console_init);


/*
 * We do this after core stuff, but before the drivers.
 */
postcore_initcall(kvm_devices_init);
Commit	Line	Data
e976a2b9 CB	1	/*
	2	* kvm_virtio.c - virtio for kvm on s390
	3	*
	4	* Copyright IBM Corp. 2008
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License (version 2 only)
	8	* as published by the Free Software Foundation.
	9	*
	10	* Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
	11	*/
	12
052ff461	13	#include <linux/kernel_stat.h>
e976a2b9 CB	14	#include <linux/init.h>
	15	#include <linux/bootmem.h>
	16	#include <linux/err.h>
	17	#include <linux/virtio.h>
	18	#include <linux/virtio_config.h>
5a0e3ad6	19	#include <linux/slab.h>
faeba830	20	#include <linux/virtio_console.h>
e976a2b9 CB	21	#include <linux/interrupt.h>
e976a2b9 CB	22	#include <linux/virtio_ring.h>
3a4c5d59	23	#include <linux/export.h>
17f34580	24	#include <linux/pfn.h>
e976a2b9 CB	25	#include <asm/io.h>
	26	#include <asm/kvm_para.h>
	27	#include <asm/kvm_virtio.h>
	28	#include <asm/setup.h>
052ff461	29	#include <asm/irq.h>
e976a2b9 CB	30
	31	#define VIRTIO_SUBCODE_64 0x0D00
	32
	33	/*
	34	* The pointer to our (page) of device descriptions.
	35	*/
	36	static void *kvm_devices;
c4736d96	37	static struct work_struct hotplug_work;
e976a2b9	38
e976a2b9 CB	39	struct kvm_device {
	40	struct virtio_device vdev;
	41	struct kvm_device_desc *desc;
	42	};
	43
	44	#define to_kvmdev(vd) container_of(vd, struct kvm_device, vdev)
	45
	46	/*
	47	* memory layout:
	48	* - kvm_device_descriptor
	49	* struct kvm_device_desc
	50	* - configuration
	51	* struct kvm_vqconfig
	52	* - feature bits
	53	* - config space
	54	*/
	55	static struct kvm_vqconfig kvm_vq_config(const struct kvm_device_desc desc)
	56	{
	57	return (struct kvm_vqconfig *)(desc + 1);
	58	}
	59
	60	static u8 kvm_vq_features(const struct kvm_device_desc desc)
	61	{
	62	return (u8 *)(kvm_vq_config(desc) + desc->num_vq);
	63	}
	64
	65	static u8 kvm_vq_configspace(const struct kvm_device_desc desc)
	66	{
	67	return kvm_vq_features(desc) + desc->feature_len * 2;
	68	}
	69
	70	/*
	71	* The total size of the config page used by this device (incl. desc)
	72	*/
	73	static unsigned desc_size(const struct kvm_device_desc *desc)
	74	{
	75	return sizeof(*desc)
	76	+ desc->num_vq * sizeof(struct kvm_vqconfig)
	77	+ desc->feature_len * 2
	78	+ desc->config_len;
	79	}
	80
5ca9fd54 HC	81	/* This gets the device's feature bits. */
5ca9fd54 HC	82	static u32 kvm_get_features(struct virtio_device *vdev)
e976a2b9	83	{
5ca9fd54 HC	84	unsigned int i;
5ca9fd54 HC	85	u32 features = 0;
e976a2b9	86	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
5ca9fd54	87	u8 *in_features = kvm_vq_features(desc);
e976a2b9	88
5ca9fd54 HC	89	for (i = 0; i < min(desc->feature_len * 8, 32); i++)
	90	if (in_features[i / 8] & (1 << (i % 8)))
	91	features \|= (1 << i);
	92	return features;
	93	}
e976a2b9	94
c624896e	95	static void kvm_finalize_features(struct virtio_device *vdev)
5ca9fd54	96	{
c624896e	97	unsigned int i, bits;
5ca9fd54 HC	98	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	99	/* Second half of bitmap is features we accept. */
	100	u8 *out_features = kvm_vq_features(desc) + desc->feature_len;
e976a2b9	101
e34f8725 RR	102	/* Give virtio_ring a chance to accept features. */
	103	vring_transport_features(vdev);
	104
5ca9fd54	105	memset(out_features, 0, desc->feature_len);
c624896e RR	106	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
	107	for (i = 0; i < bits; i++) {
	108	if (test_bit(i, vdev->features))
5ca9fd54 HC	109	out_features[i / 8] \|= (1 << (i % 8));
5ca9fd54 HC	110	}
e976a2b9 CB	111	}
	112
	113	/*
	114	* Reading and writing elements in config space
	115	*/
	116	static void kvm_get(struct virtio_device *vdev, unsigned int offset,
	117	void *buf, unsigned len)
	118	{
	119	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	120
	121	BUG_ON(offset + len > desc->config_len);
	122	memcpy(buf, kvm_vq_configspace(desc) + offset, len);
	123	}
	124
	125	static void kvm_set(struct virtio_device *vdev, unsigned int offset,
	126	const void *buf, unsigned len)
	127	{
	128	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	129
	130	BUG_ON(offset + len > desc->config_len);
	131	memcpy(kvm_vq_configspace(desc) + offset, buf, len);
	132	}
	133
	134	/*
	135	* The operations to get and set the status word just access
	136	* the status field of the device descriptor. set_status will also
	137	* make a hypercall to the host, to tell about status changes
	138	*/
	139	static u8 kvm_get_status(struct virtio_device *vdev)
	140	{
	141	return to_kvmdev(vdev)->desc->status;
	142	}
	143
	144	static void kvm_set_status(struct virtio_device *vdev, u8 status)
	145	{
	146	BUG_ON(!status);
	147	to_kvmdev(vdev)->desc->status = status;
	148	kvm_hypercall1(KVM_S390_VIRTIO_SET_STATUS,
	149	(unsigned long) to_kvmdev(vdev)->desc);
	150	}
	151
	152	/*
	153	* To reset the device, we use the KVM_VIRTIO_RESET hypercall, using the
	154	* descriptor address. The Host will zero the status and all the
	155	* features.
	156	*/
	157	static void kvm_reset(struct virtio_device *vdev)
	158	{
	159	kvm_hypercall1(KVM_S390_VIRTIO_RESET,
	160	(unsigned long) to_kvmdev(vdev)->desc);
	161	}
	162
	163	/*
	164	* When the virtio_ring code wants to notify the Host, it calls us here and we
	165	* make a hypercall. We hand the address of the virtqueue so the Host
	166	* knows which virtqueue we're talking about.
	167	*/
	168	static void kvm_notify(struct virtqueue *vq)
	169	{
	170	struct kvm_vqconfig *config = vq->priv;
	171
	172	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, config->address);
	173	}
	174
175	/*
176	* This routine finds the first virtqueue described in the configuration of
177	* this device and sets it up.
178	*/
179	static struct virtqueue kvm_find_vq(struct virtio_device vdev,
9499f5e7 RR	180	unsigned index,
	181	void (callback)(struct virtqueue vq),
	182	const char *name)
e976a2b9 CB	183	{
	184	struct kvm_device *kdev = to_kvmdev(vdev);
	185	struct kvm_vqconfig *config;
	186	struct virtqueue *vq;
	187	int err;
	188
	189	if (index >= kdev->desc->num_vq)
	190	return ERR_PTR(-ENOENT);
	191
	192	config = kvm_vq_config(kdev->desc)+index;
	193
17f34580	194	err = vmem_add_mapping(config->address,
db405988 RR	195	vring_size(config->num,
db405988 RR	196	KVM_S390_VIRTIO_RING_ALIGN));
17f34580	197	if (err)
e976a2b9	198	goto out;
e976a2b9	199
87c7d57c RR	200	vq = vring_new_virtqueue(config->num, KVM_S390_VIRTIO_RING_ALIGN,
87c7d57c RR	201	vdev, (void *) config->address,
9499f5e7	202	kvm_notify, callback, name);
e976a2b9 CB	203	if (!vq) {
	204	err = -ENOMEM;
	205	goto unmap;
	206	}
	207
	208	/*
	209	* register a callback token
	210	* The host will sent this via the external interrupt parameter
	211	*/
	212	config->token = (u64) vq;
	213
	214	vq->priv = config;
	215	return vq;
	216	unmap:
17f34580	217	vmem_remove_mapping(config->address,
db405988 RR	218	vring_size(config->num,
db405988 RR	219	KVM_S390_VIRTIO_RING_ALIGN));
e976a2b9 CB	220	out:
	221	return ERR_PTR(err);
	222	}
	223
	224	static void kvm_del_vq(struct virtqueue *vq)
	225	{
	226	struct kvm_vqconfig *config = vq->priv;
	227
	228	vring_del_virtqueue(vq);
17f34580	229	vmem_remove_mapping(config->address,
db405988 RR	230	vring_size(config->num,
db405988 RR	231	KVM_S390_VIRTIO_RING_ALIGN));
e976a2b9 CB	232	}
e976a2b9 CB	233
d2a7ddda MT	234	static void kvm_del_vqs(struct virtio_device *vdev)
	235	{
	236	struct virtqueue vq, n;
	237
	238	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
	239	kvm_del_vq(vq);
	240	}
	241
	242	static int kvm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
	243	struct virtqueue *vqs[],
	244	vq_callback_t *callbacks[],
	245	const char *names[])
	246	{
	247	struct kvm_device *kdev = to_kvmdev(vdev);
	248	int i;
	249
	250	/* We must have this many virtqueues. */
	251	if (nvqs > kdev->desc->num_vq)
	252	return -ENOENT;
	253
	254	for (i = 0; i < nvqs; ++i) {
	255	vqs[i] = kvm_find_vq(vdev, i, callbacks[i], names[i]);
	256	if (IS_ERR(vqs[i]))
	257	goto error;
	258	}
	259	return 0;
	260
	261	error:
	262	kvm_del_vqs(vdev);
	263	return PTR_ERR(vqs[i]);
	264	}
	265
e976a2b9 CB	266	/*
	267	* The config ops structure as defined by virtio config
	268	*/
	269	static struct virtio_config_ops kvm_vq_configspace_ops = {
5ca9fd54	270	.get_features = kvm_get_features,
c624896e	271	.finalize_features = kvm_finalize_features,
e976a2b9 CB	272	.get = kvm_get,
	273	.set = kvm_set,
	274	.get_status = kvm_get_status,
	275	.set_status = kvm_set_status,
	276	.reset = kvm_reset,
d2a7ddda MT	277	.find_vqs = kvm_find_vqs,
d2a7ddda MT	278	.del_vqs = kvm_del_vqs,
e976a2b9 CB	279	};
	280
	281	/*
	282	* The root device for the kvm virtio devices.
	283	* This makes them appear as /sys/devices/kvm_s390/0,1,2 not /sys/devices/0,1,2.
	284	*/
37f1c012	285	static struct device *kvm_root;
e976a2b9 CB	286
	287	/*
	288	* adds a new device and register it with virtio
	289	* appropriate drivers are loaded by the device model
	290	*/
b769f579	291	static void add_kvm_device(struct kvm_device_desc *d, unsigned int offset)
e976a2b9 CB	292	{
	293	struct kvm_device *kdev;
	294
	295	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
	296	if (!kdev) {
b769f579 RR	297	printk(KERN_EMERG "Cannot allocate kvm dev %u type %u\n",
b769f579 RR	298	offset, d->type);
e976a2b9 CB	299	return;
	300	}
	301
37f1c012	302	kdev->vdev.dev.parent = kvm_root;
e976a2b9 CB	303	kdev->vdev.id.device = d->type;
	304	kdev->vdev.config = &kvm_vq_configspace_ops;
	305	kdev->desc = d;
	306
	307	if (register_virtio_device(&kdev->vdev) != 0) {
b769f579 RR	308	printk(KERN_ERR "Failed to register kvm device %u type %u\n",
b769f579 RR	309	offset, d->type);
e976a2b9 CB	310	kfree(kdev);
	311	}
	312	}
	313
	314	/*
	315	* scan_devices() simply iterates through the device page.
	316	* The type 0 is reserved to mean "end of devices".
	317	*/
	318	static void scan_devices(void)
	319	{
	320	unsigned int i;
	321	struct kvm_device_desc *d;
	322
	323	for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
	324	d = kvm_devices + i;
	325
	326	if (d->type == 0)
	327	break;
	328
b769f579	329	add_kvm_device(d, i);
e976a2b9 CB	330	}
	331	}
	332
cefa33e2 AG	333	/*
	334	* match for a kvm device with a specific desc pointer
	335	*/
	336	static int match_desc(struct device dev, void data)
	337	{
7bf4074d MS	338	struct virtio_device *vdev = dev_to_virtio(dev);
7bf4074d MS	339	struct kvm_device *kdev = to_kvmdev(vdev);
cefa33e2	340
7bf4074d	341	return kdev->desc == data;
cefa33e2 AG	342	}
	343
	344	/*
	345	* hotplug_device tries to find changes in the device page.
	346	*/
	347	static void hotplug_devices(struct work_struct *dummy)
	348	{
	349	unsigned int i;
	350	struct kvm_device_desc *d;
	351	struct device *dev;
	352
	353	for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
	354	d = kvm_devices + i;
	355
	356	/* end of list */
	357	if (d->type == 0)
	358	break;
	359
	360	/* device already exists */
	361	dev = device_find_child(kvm_root, d, match_desc);
	362	if (dev) {
	363	/* XXX check for hotplug remove */
	364	put_device(dev);
	365	continue;
	366	}
	367
	368	/* new device */
	369	printk(KERN_INFO "Adding new virtio device %p\n", d);
	370	add_kvm_device(d, i);
	371	}
	372	}
	373
e976a2b9 CB	374	/*
	375	* we emulate the request_irq behaviour on top of s390 extints
	376	*/
f6649a7e MS	377	static void kvm_extint_handler(unsigned int ext_int_code,
f6649a7e MS	378	unsigned int param32, unsigned long param64)
e976a2b9	379	{
be3c5832 CB	380	struct virtqueue *vq;
be3c5832 CB	381	u16 subcode;
fc678d67	382	u32 param;
e976a2b9	383
f6649a7e	384	subcode = ext_int_code >> 16;
e976a2b9 CB	385	if ((subcode & 0xff00) != VIRTIO_SUBCODE_64)
e976a2b9 CB	386	return;
a9851832	387	kstat_cpu(smp_processor_id()).irqs[EXTINT_VRT]++;
e976a2b9	388
be3c5832	389	/* The LSB might be overloaded, we have to mask it */
f6649a7e	390	vq = (struct virtqueue *)(param64 & ~1UL);
be3c5832	391
fc678d67	392	/* We use ext_params to decide what this interrupt means */
f6649a7e	393	param = param32 & VIRTIO_PARAM_MASK;
be3c5832	394
fc678d67 AG	395	switch (param) {
	396	case VIRTIO_PARAM_CONFIG_CHANGED:
	397	{
be3c5832 CB	398	struct virtio_driver *drv;
	399	drv = container_of(vq->vdev->dev.driver,
	400	struct virtio_driver, driver);
	401	if (drv->config_changed)
	402	drv->config_changed(vq->vdev);
fc678d67 AG	403
	404	break;
	405	}
cefa33e2 AG	406	case VIRTIO_PARAM_DEV_ADD:
	407	schedule_work(&hotplug_work);
	408	break;
fc678d67 AG	409	case VIRTIO_PARAM_VRING_INTERRUPT:
fc678d67 AG	410	default:
be3c5832	411	vring_interrupt(0, vq);
fc678d67 AG	412	break;
fc678d67 AG	413	}
e976a2b9 CB	414	}
	415
	416	/*
	417	* Init function for virtio
	418	* devices are in a single page above top of "normal" mem
	419	*/
	420	static int __init kvm_devices_init(void)
	421	{
	422	int rc;
	423
	424	if (!MACHINE_IS_KVM)
	425	return -ENODEV;
	426
035da16f	427	kvm_root = root_device_register("kvm_s390");
37f1c012 CH	428	if (IS_ERR(kvm_root)) {
37f1c012 CH	429	rc = PTR_ERR(kvm_root);
e976a2b9 CB	430	printk(KERN_ERR "Could not register kvm_s390 root device");
	431	return rc;
	432	}
	433
cc835f78	434	rc = vmem_add_mapping(real_memory_size, PAGE_SIZE);
17f34580	435	if (rc) {
035da16f	436	root_device_unregister(kvm_root);
17f34580	437	return rc;
e976a2b9 CB	438	}
e976a2b9 CB	439
cc835f78	440	kvm_devices = (void *) real_memory_size;
e976a2b9	441
cefa33e2 AG	442	INIT_WORK(&hotplug_work, hotplug_devices);
cefa33e2 AG	443
df7997ab	444	service_subclass_irq_register();
e976a2b9 CB	445	register_external_interrupt(0x2603, kvm_extint_handler);
	446
	447	scan_devices();
	448	return 0;
	449	}
	450
faeba830 CB	451	/* code for early console output with virtio_console */
	452	static __init int early_put_chars(u32 vtermno, const char *buf, int count)
	453	{
	454	char scratch[17];
	455	unsigned int len = count;
	456
	457	if (len > sizeof(scratch) - 1)
	458	len = sizeof(scratch) - 1;
	459	scratch[len] = '\0';
	460	memcpy(scratch, buf, len);
	461	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, __pa(scratch));
	462	return len;
	463	}
	464
c4de0c1a	465	static int __init s390_virtio_console_init(void)
faeba830	466	{
c4de0c1a HB	467	if (!MACHINE_IS_KVM)
	468	return -ENODEV;
	469	return virtio_cons_early_init(early_put_chars);
faeba830	470	}
c4de0c1a HB	471	console_initcall(s390_virtio_console_init);
c4de0c1a HB	472
faeba830	473
e976a2b9 CB	474	/*
	475	* We do this after core stuff, but before the drivers.
	476	*/
	477	postcore_initcall(kvm_devices_init);