[net-next-2.6.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/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/pfn.h>
#include <asm/io.h>
#include <asm/kvm_para.h>
#include <asm/kvm_virtio.h>
#include <asm/setup.h>
#include <asm/s390_ext.h>

#define VIRTIO_SUBCODE_64 0x0D00

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

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);
	}
}

/*
 * we emulate the request_irq behaviour on top of s390 extints
 */
static void kvm_extint_handler(u16 code)
{
	struct virtqueue *vq;
	u16 subcode;
	int config_changed;

	subcode = S390_lowcore.cpu_addr;
	if ((subcode & 0xff00) != VIRTIO_SUBCODE_64)
		return;

	/* The LSB might be overloaded, we have to mask it */
	vq = (struct virtqueue *)(S390_lowcore.ext_params2 & ~1UL);

	/* We use the LSB of extparam, to decide, if this interrupt is a config
	 * change or a "standard" interrupt */
	config_changed = S390_lowcore.ext_params & 1;

	if (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);
	} else
		vring_interrupt(0, vq);
}

/*
 * 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;

	ctl_set_bit(0, 9);
	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
	13	#include <linux/init.h>
	14	#include <linux/bootmem.h>
	15	#include <linux/err.h>
	16	#include <linux/virtio.h>
	17	#include <linux/virtio_config.h>
5a0e3ad6	18	#include <linux/slab.h>
faeba830	19	#include <linux/virtio_console.h>
e976a2b9 CB	20	#include <linux/interrupt.h>
e976a2b9 CB	21	#include <linux/virtio_ring.h>
17f34580	22	#include <linux/pfn.h>
e976a2b9 CB	23	#include <asm/io.h>
	24	#include <asm/kvm_para.h>
	25	#include <asm/kvm_virtio.h>
	26	#include <asm/setup.h>
	27	#include <asm/s390_ext.h>
	28
	29	#define VIRTIO_SUBCODE_64 0x0D00
	30
	31	/*
	32	* The pointer to our (page) of device descriptions.
	33	*/
	34	static void *kvm_devices;
	35
e976a2b9 CB	36	struct kvm_device {
	37	struct virtio_device vdev;
	38	struct kvm_device_desc *desc;
	39	};
	40
	41	#define to_kvmdev(vd) container_of(vd, struct kvm_device, vdev)
	42
	43	/*
	44	* memory layout:
	45	* - kvm_device_descriptor
	46	* struct kvm_device_desc
	47	* - configuration
	48	* struct kvm_vqconfig
	49	* - feature bits
	50	* - config space
	51	*/
	52	static struct kvm_vqconfig kvm_vq_config(const struct kvm_device_desc desc)
	53	{
	54	return (struct kvm_vqconfig *)(desc + 1);
	55	}
	56
	57	static u8 kvm_vq_features(const struct kvm_device_desc desc)
	58	{
	59	return (u8 *)(kvm_vq_config(desc) + desc->num_vq);
	60	}
	61
	62	static u8 kvm_vq_configspace(const struct kvm_device_desc desc)
	63	{
	64	return kvm_vq_features(desc) + desc->feature_len * 2;
	65	}
	66
	67	/*
	68	* The total size of the config page used by this device (incl. desc)
	69	*/
	70	static unsigned desc_size(const struct kvm_device_desc *desc)
	71	{
	72	return sizeof(*desc)
	73	+ desc->num_vq * sizeof(struct kvm_vqconfig)
	74	+ desc->feature_len * 2
	75	+ desc->config_len;
	76	}
	77
5ca9fd54 HC	78	/* This gets the device's feature bits. */
5ca9fd54 HC	79	static u32 kvm_get_features(struct virtio_device *vdev)
e976a2b9	80	{
5ca9fd54 HC	81	unsigned int i;
5ca9fd54 HC	82	u32 features = 0;
e976a2b9	83	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
5ca9fd54	84	u8 *in_features = kvm_vq_features(desc);
e976a2b9	85
5ca9fd54 HC	86	for (i = 0; i < min(desc->feature_len * 8, 32); i++)
	87	if (in_features[i / 8] & (1 << (i % 8)))
	88	features \|= (1 << i);
	89	return features;
	90	}
e976a2b9	91
c624896e	92	static void kvm_finalize_features(struct virtio_device *vdev)
5ca9fd54	93	{
c624896e	94	unsigned int i, bits;
5ca9fd54 HC	95	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	96	/* Second half of bitmap is features we accept. */
	97	u8 *out_features = kvm_vq_features(desc) + desc->feature_len;
e976a2b9	98
e34f8725 RR	99	/* Give virtio_ring a chance to accept features. */
	100	vring_transport_features(vdev);
	101
5ca9fd54	102	memset(out_features, 0, desc->feature_len);
c624896e RR	103	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
	104	for (i = 0; i < bits; i++) {
	105	if (test_bit(i, vdev->features))
5ca9fd54 HC	106	out_features[i / 8] \|= (1 << (i % 8));
5ca9fd54 HC	107	}
e976a2b9 CB	108	}
	109
	110	/*
	111	* Reading and writing elements in config space
	112	*/
	113	static void kvm_get(struct virtio_device *vdev, unsigned int offset,
	114	void *buf, unsigned len)
	115	{
	116	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	117
	118	BUG_ON(offset + len > desc->config_len);
	119	memcpy(buf, kvm_vq_configspace(desc) + offset, len);
	120	}
	121
	122	static void kvm_set(struct virtio_device *vdev, unsigned int offset,
	123	const void *buf, unsigned len)
	124	{
	125	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	126
	127	BUG_ON(offset + len > desc->config_len);
	128	memcpy(kvm_vq_configspace(desc) + offset, buf, len);
	129	}
	130
	131	/*
	132	* The operations to get and set the status word just access
	133	* the status field of the device descriptor. set_status will also
	134	* make a hypercall to the host, to tell about status changes
	135	*/
	136	static u8 kvm_get_status(struct virtio_device *vdev)
	137	{
	138	return to_kvmdev(vdev)->desc->status;
	139	}
	140
	141	static void kvm_set_status(struct virtio_device *vdev, u8 status)
	142	{
	143	BUG_ON(!status);
	144	to_kvmdev(vdev)->desc->status = status;
	145	kvm_hypercall1(KVM_S390_VIRTIO_SET_STATUS,
	146	(unsigned long) to_kvmdev(vdev)->desc);
	147	}
	148
	149	/*
	150	* To reset the device, we use the KVM_VIRTIO_RESET hypercall, using the
	151	* descriptor address. The Host will zero the status and all the
	152	* features.
	153	*/
	154	static void kvm_reset(struct virtio_device *vdev)
	155	{
	156	kvm_hypercall1(KVM_S390_VIRTIO_RESET,
	157	(unsigned long) to_kvmdev(vdev)->desc);
	158	}
	159
	160	/*
	161	* When the virtio_ring code wants to notify the Host, it calls us here and we
	162	* make a hypercall. We hand the address of the virtqueue so the Host
	163	* knows which virtqueue we're talking about.
	164	*/
	165	static void kvm_notify(struct virtqueue *vq)
	166	{
	167	struct kvm_vqconfig *config = vq->priv;
	168
	169	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, config->address);
	170	}
	171
172	/*
173	* This routine finds the first virtqueue described in the configuration of
174	* this device and sets it up.
175	*/
176	static struct virtqueue kvm_find_vq(struct virtio_device vdev,
9499f5e7 RR	177	unsigned index,
	178	void (callback)(struct virtqueue vq),
	179	const char *name)
e976a2b9 CB	180	{
	181	struct kvm_device *kdev = to_kvmdev(vdev);
	182	struct kvm_vqconfig *config;
	183	struct virtqueue *vq;
	184	int err;
	185
	186	if (index >= kdev->desc->num_vq)
	187	return ERR_PTR(-ENOENT);
	188
	189	config = kvm_vq_config(kdev->desc)+index;
	190
17f34580	191	err = vmem_add_mapping(config->address,
db405988 RR	192	vring_size(config->num,
db405988 RR	193	KVM_S390_VIRTIO_RING_ALIGN));
17f34580	194	if (err)
e976a2b9	195	goto out;
e976a2b9	196
87c7d57c RR	197	vq = vring_new_virtqueue(config->num, KVM_S390_VIRTIO_RING_ALIGN,
87c7d57c RR	198	vdev, (void *) config->address,
9499f5e7	199	kvm_notify, callback, name);
e976a2b9 CB	200	if (!vq) {
	201	err = -ENOMEM;
	202	goto unmap;
	203	}
	204
	205	/*
	206	* register a callback token
	207	* The host will sent this via the external interrupt parameter
	208	*/
	209	config->token = (u64) vq;
	210
	211	vq->priv = config;
	212	return vq;
	213	unmap:
17f34580	214	vmem_remove_mapping(config->address,
db405988 RR	215	vring_size(config->num,
db405988 RR	216	KVM_S390_VIRTIO_RING_ALIGN));
e976a2b9 CB	217	out:
	218	return ERR_PTR(err);
	219	}
	220
	221	static void kvm_del_vq(struct virtqueue *vq)
	222	{
	223	struct kvm_vqconfig *config = vq->priv;
	224
	225	vring_del_virtqueue(vq);
17f34580	226	vmem_remove_mapping(config->address,
db405988 RR	227	vring_size(config->num,
db405988 RR	228	KVM_S390_VIRTIO_RING_ALIGN));
e976a2b9 CB	229	}
e976a2b9 CB	230
d2a7ddda MT	231	static void kvm_del_vqs(struct virtio_device *vdev)
	232	{
	233	struct virtqueue vq, n;
	234
	235	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
	236	kvm_del_vq(vq);
	237	}
	238
	239	static int kvm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
	240	struct virtqueue *vqs[],
	241	vq_callback_t *callbacks[],
	242	const char *names[])
	243	{
	244	struct kvm_device *kdev = to_kvmdev(vdev);
	245	int i;
	246
	247	/* We must have this many virtqueues. */
	248	if (nvqs > kdev->desc->num_vq)
	249	return -ENOENT;
	250
	251	for (i = 0; i < nvqs; ++i) {
	252	vqs[i] = kvm_find_vq(vdev, i, callbacks[i], names[i]);
	253	if (IS_ERR(vqs[i]))
	254	goto error;
	255	}
	256	return 0;
	257
	258	error:
	259	kvm_del_vqs(vdev);
	260	return PTR_ERR(vqs[i]);
	261	}
	262
e976a2b9 CB	263	/*
	264	* The config ops structure as defined by virtio config
	265	*/
	266	static struct virtio_config_ops kvm_vq_configspace_ops = {
5ca9fd54	267	.get_features = kvm_get_features,
c624896e	268	.finalize_features = kvm_finalize_features,
e976a2b9 CB	269	.get = kvm_get,
	270	.set = kvm_set,
	271	.get_status = kvm_get_status,
	272	.set_status = kvm_set_status,
	273	.reset = kvm_reset,
d2a7ddda MT	274	.find_vqs = kvm_find_vqs,
d2a7ddda MT	275	.del_vqs = kvm_del_vqs,
e976a2b9 CB	276	};
	277
	278	/*
	279	* The root device for the kvm virtio devices.
	280	* This makes them appear as /sys/devices/kvm_s390/0,1,2 not /sys/devices/0,1,2.
	281	*/
37f1c012	282	static struct device *kvm_root;
e976a2b9 CB	283
	284	/*
	285	* adds a new device and register it with virtio
	286	* appropriate drivers are loaded by the device model
	287	*/
b769f579	288	static void add_kvm_device(struct kvm_device_desc *d, unsigned int offset)
e976a2b9 CB	289	{
	290	struct kvm_device *kdev;
	291
	292	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
	293	if (!kdev) {
b769f579 RR	294	printk(KERN_EMERG "Cannot allocate kvm dev %u type %u\n",
b769f579 RR	295	offset, d->type);
e976a2b9 CB	296	return;
	297	}
	298
37f1c012	299	kdev->vdev.dev.parent = kvm_root;
e976a2b9 CB	300	kdev->vdev.id.device = d->type;
	301	kdev->vdev.config = &kvm_vq_configspace_ops;
	302	kdev->desc = d;
	303
	304	if (register_virtio_device(&kdev->vdev) != 0) {
b769f579 RR	305	printk(KERN_ERR "Failed to register kvm device %u type %u\n",
b769f579 RR	306	offset, d->type);
e976a2b9 CB	307	kfree(kdev);
	308	}
	309	}
	310
	311	/*
	312	* scan_devices() simply iterates through the device page.
	313	* The type 0 is reserved to mean "end of devices".
	314	*/
	315	static void scan_devices(void)
	316	{
	317	unsigned int i;
	318	struct kvm_device_desc *d;
	319
	320	for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
	321	d = kvm_devices + i;
	322
	323	if (d->type == 0)
	324	break;
	325
b769f579	326	add_kvm_device(d, i);
e976a2b9 CB	327	}
	328	}
	329
	330	/*
	331	* we emulate the request_irq behaviour on top of s390 extints
	332	*/
	333	static void kvm_extint_handler(u16 code)
	334	{
be3c5832 CB	335	struct virtqueue *vq;
	336	u16 subcode;
	337	int config_changed;
e976a2b9	338
be3c5832	339	subcode = S390_lowcore.cpu_addr;
e976a2b9 CB	340	if ((subcode & 0xff00) != VIRTIO_SUBCODE_64)
	341	return;
	342
be3c5832	343	/* The LSB might be overloaded, we have to mask it */
cbb870c8	344	vq = (struct virtqueue *)(S390_lowcore.ext_params2 & ~1UL);
be3c5832 CB	345
	346	/* We use the LSB of extparam, to decide, if this interrupt is a config
	347	* change or a "standard" interrupt */
cbb870c8	348	config_changed = S390_lowcore.ext_params & 1;
be3c5832 CB	349
	350	if (config_changed) {
	351	struct virtio_driver *drv;
	352	drv = container_of(vq->vdev->dev.driver,
	353	struct virtio_driver, driver);
	354	if (drv->config_changed)
	355	drv->config_changed(vq->vdev);
	356	} else
	357	vring_interrupt(0, vq);
e976a2b9 CB	358	}
	359
	360	/*
	361	* Init function for virtio
	362	* devices are in a single page above top of "normal" mem
	363	*/
	364	static int __init kvm_devices_init(void)
	365	{
	366	int rc;
	367
	368	if (!MACHINE_IS_KVM)
	369	return -ENODEV;
	370
035da16f	371	kvm_root = root_device_register("kvm_s390");
37f1c012 CH	372	if (IS_ERR(kvm_root)) {
37f1c012 CH	373	rc = PTR_ERR(kvm_root);
e976a2b9 CB	374	printk(KERN_ERR "Could not register kvm_s390 root device");
	375	return rc;
	376	}
	377
cc835f78	378	rc = vmem_add_mapping(real_memory_size, PAGE_SIZE);
17f34580	379	if (rc) {
035da16f	380	root_device_unregister(kvm_root);
17f34580	381	return rc;
e976a2b9 CB	382	}
e976a2b9 CB	383
cc835f78	384	kvm_devices = (void *) real_memory_size;
e976a2b9 CB	385
	386	ctl_set_bit(0, 9);
	387	register_external_interrupt(0x2603, kvm_extint_handler);
	388
	389	scan_devices();
	390	return 0;
	391	}
	392
faeba830 CB	393	/* code for early console output with virtio_console */
	394	static __init int early_put_chars(u32 vtermno, const char *buf, int count)
	395	{
	396	char scratch[17];
	397	unsigned int len = count;
	398
	399	if (len > sizeof(scratch) - 1)
	400	len = sizeof(scratch) - 1;
	401	scratch[len] = '\0';
	402	memcpy(scratch, buf, len);
	403	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, __pa(scratch));
	404	return len;
	405	}
	406
c4de0c1a	407	static int __init s390_virtio_console_init(void)
faeba830	408	{
c4de0c1a HB	409	if (!MACHINE_IS_KVM)
	410	return -ENODEV;
	411	return virtio_cons_early_init(early_put_chars);
faeba830	412	}
c4de0c1a HB	413	console_initcall(s390_virtio_console_init);
c4de0c1a HB	414
faeba830	415
e976a2b9 CB	416	/*
	417	* We do this after core stuff, but before the drivers.
	418	*/
	419	postcore_initcall(kvm_devices_init);