Release 4.7 drivers/s390/virtio/kvm_virtio.c

Directory: drivers/s390/virtio
/*
 * 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/sclp.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);
}

Contributors
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christian borntraeger christian borntraeger 26 100.00% 1 100.00%
Total 26 100.00% 1 100.00%



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

Contributors
Person Tokens Prop Commits CommitProp
christian borntraeger christian borntraeger 29 100.00% 1 100.00%
Total 29 100.00% 1 100.00%



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

Contributors
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christian borntraeger christian borntraeger 25 100.00% 1 100.00%
Total 25 100.00% 1 100.00%

/*
 * 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;
}

Contributors
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christian borntraeger christian borntraeger 39 100.00% 1 100.00%
Total 39 100.00% 1 100.00%

/* This gets the device's feature bits. */


static u64 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;
}

Contributors
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heiko carstens heiko carstens 47 50.54% 1 33.33%
christian borntraeger christian borntraeger 45 48.39% 1 33.33%
michael s. tsirkin michael s. tsirkin 1 1.08% 1 33.33%
Total 93 100.00% 3 100.00%



static int 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);

	/* Make sure we don't have any features > 32 bits! */
	BUG_ON((u32)vdev->features != vdev->features);

	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 (__virtio_test_bit(vdev, i))
			out_features[i / 8] |= (1 << (i % 8));
	}

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
heiko carstens heiko carstens 67 48.20% 1 14.29%
rusty russell rusty russell 33 23.74% 2 28.57%
michael s. tsirkin michael s. tsirkin 22 15.83% 3 42.86%
christian borntraeger christian borntraeger 17 12.23% 1 14.29%
Total 139 100.00% 7 100.00%

/*
 * 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);
}

Contributors
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christian borntraeger christian borntraeger 59 100.00% 1 100.00%
Total 59 100.00% 1 100.00%



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);
}

Contributors
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christian borntraeger christian borntraeger 60 100.00% 1 100.00%
Total 60 100.00% 1 100.00%

/*
 * 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;
}

Contributors
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christian borntraeger christian borntraeger 21 100.00% 1 100.00%
Total 21 100.00% 1 100.00%



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);
}

Contributors
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christian borntraeger christian borntraeger 47 100.00% 1 100.00%
Total 47 100.00% 1 100.00%

/*
 * 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);
}

Contributors
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christian borntraeger christian borntraeger 27 100.00% 1 100.00%
Total 27 100.00% 1 100.00%

/*
 * 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 bool kvm_notify(struct virtqueue *vq)
{
	long rc;
	struct kvm_vqconfig *config = vq->priv;

	rc = kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, config->address);
	if (rc < 0)
		return false;
	return true;
}

Contributors
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christian borntraeger christian borntraeger 28 60.87% 1 50.00%
heinz graalfs heinz graalfs 18 39.13% 1 50.00%
Total 46 100.00% 2 100.00%

/*
 * 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);

	if (!name)
		return NULL;

	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(index, config->num, KVM_S390_VIRTIO_RING_ALIGN,
				 vdev, true, (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);
}

Contributors
Person Tokens Prop Commits CommitProp
christian borntraeger christian borntraeger 177 85.10% 1 12.50%
rusty russell rusty russell 13 6.25% 4 50.00%
heiko carstens heiko carstens 8 3.85% 1 12.50%
michael s. tsirkin michael s. tsirkin 8 3.85% 1 12.50%
jason wang jason wang 2 0.96% 1 12.50%
Total 208 100.00% 8 100.00%



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));
}

Contributors
Person Tokens Prop Commits CommitProp
christian borntraeger christian borntraeger 39 95.12% 1 33.33%
rusty russell rusty russell 1 2.44% 1 33.33%
heiko carstens heiko carstens 1 2.44% 1 33.33%
Total 41 100.00% 3 100.00%



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);
}

Contributors
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michael s. tsirkin michael s. tsirkin 34 100.00% 1 100.00%
Total 34 100.00% 1 100.00%



static int kvm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
			struct virtqueue *vqs[],
			vq_callback_t *callbacks[],
			const char * const 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]);
}

Contributors
Person Tokens Prop Commits CommitProp
michael s. tsirkin michael s. tsirkin 128 99.22% 1 50.00%
stefan hajnoczi stefan hajnoczi 1 0.78% 1 50.00%
Total 129 100.00% 2 100.00%



static const char *kvm_bus_name(struct virtio_device *vdev)
{
	return "";
}

Contributors
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rick jones rick jones 16 100.00% 1 100.00%
Total 16 100.00% 1 100.00%

/*
 * The config ops structure as defined by virtio config
 */

static const 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,
	.bus_name = kvm_bus_name,
};

/*
 * 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);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
christian borntraeger christian borntraeger 106 87.60% 1 50.00%
rusty russell rusty russell 15 12.40% 1 50.00%
Total 121 100.00% 2 100.00%

/*
 * 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);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
christian borntraeger christian borntraeger 56 96.55% 1 50.00%
rusty russell rusty russell 2 3.45% 1 50.00%
Total 58 100.00% 2 100.00%

/*
 * 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;
}

Contributors
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alexander graf alexander graf 25 59.52% 1 50.00%
martin schwidefsky martin schwidefsky 17 40.48% 1 50.00%
Total 42 100.00% 2 100.00%

/*
 * 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);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
alexander graf alexander graf 101 100.00% 1 100.00%
Total 101 100.00% 1 100.00%

/*
 * we emulate the request_irq behaviour on top of s390 extints
 */


static void kvm_extint_handler(struct ext_code ext_code,
			       unsigned int param32, unsigned long param64)
{
	struct virtqueue *vq;
	u32 param;

	if ((ext_code.subcode & 0xff00) != VIRTIO_SUBCODE_64)
		return;
	inc_irq_stat(IRQEXT_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:
		virtio_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;
	}
}

Contributors
Person Tokens Prop Commits CommitProp
christian borntraeger christian borntraeger 57 54.29% 2 22.22%
alexander graf alexander graf 27 25.71% 2 22.22%
martin schwidefsky martin schwidefsky 10 9.52% 1 11.11%
heiko carstens heiko carstens 10 9.52% 3 33.33%
michael s. tsirkin michael s. tsirkin 1 0.95% 1 11.11%
Total 105 100.00% 9 100.00%

/*
 * For s390-virtio, we expect a page above main storage containing
 * the virtio configuration. Try to actually load from this area
 * in order to figure out if the host provides this page.
 */


static int __init test_devices_support(unsigned long addr)
{
	int ret = -EIO;

	asm volatile(
                "0:     lura    0,%1\n"
                "1:     xgr     %0,%0\n"
                "2:\n"
                EX_TABLE(0b,2b)
                EX_TABLE(1b,2b)
                : "+d" (ret)
                : "a" (addr)
                : "0", "cc");
	return ret;
}
Contributors
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cornelia huck cornelia huck 23 100.00% 1 100.00%
Total 23 100.00% 1 100.00%

/*
 * Init function for virtio
 * devices are in a single page above top of "normal" + standby mem
 */


static int __init kvm_devices_init(void)
{
	int rc;
	unsigned long total_memory_size = sclp.rzm * sclp.rnmax;

	if (!MACHINE_IS_KVM)
		return -ENODEV;

	if (test_devices_support(total_memory_size) < 0)
		return -ENODEV;

	rc = vmem_add_mapping(total_memory_size, PAGE_SIZE);
	if (rc)
		return rc;

	kvm_devices = (void *) total_memory_size;

	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");
		vmem_remove_mapping(total_memory_size, PAGE_SIZE);
		return rc;
	}

	INIT_WORK(&hotplug_work, hotplug_devices);

	irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
	register_external_irq(EXT_IRQ_CP_SERVICE, kvm_extint_handler);

	scan_devices();
	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
christian borntraeger christian borntraeger 53 39.26% 1 10.00%
cornelia huck cornelia huck 48 35.56% 2 20.00%
nick wang nick wang 10 7.41% 1 10.00%
alexander graf alexander graf 8 5.93% 1 10.00%
heiko carstens heiko carstens 7 5.19% 2 20.00%
david hildenbrand david hildenbrand 6 4.44% 1 10.00%
thomas huth thomas huth 2 1.48% 1 10.00%
mark mcloughlin mark mcloughlin 1 0.74% 1 10.00%
Total 135 100.00% 10 100.00%

/* 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;
}

Contributors
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christian borntraeger christian borntraeger 79 100.00% 1 100.00%
Total 79 100.00% 1 100.00%



static int __init s390_virtio_console_init(void)
{
	if (sclp.has_vt220 || sclp.has_linemode)
		return -ENODEV;
	return virtio_cons_early_init(early_put_chars);
}
Contributors
Person Tokens Prop Commits CommitProp
hendrik brueckner hendrik brueckner 11 37.93% 1 20.00%
christian borntraeger christian borntraeger 10 34.48% 1 20.00%
david hildenbrand david hildenbrand 6 20.69% 1 20.00%
heinz graalfs heinz graalfs 1 3.45% 1 20.00%
heiko carstens heiko carstens 1 3.45% 1 20.00%
Total 29 100.00% 5 100.00%


console_initcall(s390_virtio_console_init);


/*
 * We do this after core stuff, but before the drivers.
 */

postcore_initcall(kvm_devices_init);
Overall Contributors
Person Tokens Prop Commits CommitProp
christian borntraeger christian borntraeger 1134 59.19% 3 6.52%
michael s. tsirkin michael s. tsirkin 198 10.33% 7 15.22%
alexander graf alexander graf 167 8.72% 2 4.35%
heiko carstens heiko carstens 158 8.25% 10 21.74%
cornelia huck cornelia huck 73 3.81% 2 4.35%
rusty russell rusty russell 66 3.44% 7 15.22%
martin schwidefsky martin schwidefsky 28 1.46% 3 6.52%
heinz graalfs heinz graalfs 22 1.15% 2 4.35%
rick jones rick jones 21 1.10% 1 2.17%
hendrik brueckner hendrik brueckner 16 0.84% 1 2.17%
david hildenbrand david hildenbrand 12 0.63% 1 2.17%
nick wang nick wang 11 0.57% 1 2.17%
tejun heo tejun heo 3 0.16% 1 2.17%
thomas huth thomas huth 2 0.10% 1 2.17%
jason wang jason wang 2 0.10% 1 2.17%
stefan hajnoczi stefan hajnoczi 1 0.05% 1 2.17%
mark mcloughlin mark mcloughlin 1 0.05% 1 2.17%
stephen hemminger stephen hemminger 1 0.05% 1 2.17%
Total 1916 100.00% 46 100.00%
  Directory: drivers/s390/virtio

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
	Person	Tokens	Prop	Commits	CommitProp
christian borntraeger	christian borntraeger	26	100.00%	1	100.00%
	Total	26	100.00%	1	100.00%
cregit-Linux how code gets into the kernel

Release 4.7 drivers/s390/virtio/kvm_virtio.c

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