xref: /kvmtool/virtio/blk.c (revision 4baf6f73fca645821c4fb07a8babf38988f292a1)

#include "kvm/virtio-blk.h"

#include "kvm/virtio-pci.h"

#include "kvm/disk-image.h"
#include "kvm/virtio.h"
#include "kvm/ioport.h"
#include "kvm/mutex.h"
#include "kvm/util.h"
#include "kvm/kvm.h"
#include "kvm/pci.h"

#include <linux/virtio_ring.h>
#include <linux/virtio_blk.h>

#include <inttypes.h>
#include <pthread.h>

#define VIRTIO_BLK_IRQ		14

#define NUM_VIRT_QUEUES		1

#define VIRTIO_BLK_QUEUE_SIZE	128

struct blk_device {
	pthread_mutex_t			mutex;

	struct virtio_blk_config	blk_config;
	uint32_t			host_features;
	uint32_t			guest_features;
	uint16_t			config_vector;
	uint8_t				status;
	pthread_t			io_thread;
	pthread_mutex_t		io_mutex;
	pthread_cond_t		io_cond;

	/* virtio queue */
	uint16_t			queue_selector;
	uint64_t			virtio_blk_queue_set_flags;

	struct virt_queue		vqs[NUM_VIRT_QUEUES];
};

#define DISK_SEG_MAX	126

static struct blk_device blk_device = {
	.mutex			= PTHREAD_MUTEX_INITIALIZER,

	.blk_config		= (struct virtio_blk_config) {
		/* VIRTIO_BLK_F_SEG_MAX */
		.seg_max		= DISK_SEG_MAX,
	},
	/*
	 * Note we don't set VIRTIO_BLK_F_GEOMETRY here so the
	 * node kernel will compute disk geometry by own, the
	 * same applies to VIRTIO_BLK_F_BLK_SIZE
	 */
	.host_features		= (1UL << VIRTIO_BLK_F_SEG_MAX),

	.io_mutex			= PTHREAD_MUTEX_INITIALIZER,
	.io_cond			= PTHREAD_COND_INITIALIZER
};

static bool virtio_blk_pci_io_device_specific_in(void *data, unsigned long offset, int size, uint32_t count)
{
	uint8_t *config_space = (uint8_t *) &blk_device.blk_config;

	if (size != 1 || count != 1)
		return false;

	ioport__write8(data, config_space[offset - VIRTIO_PCI_CONFIG_NOMSI]);

	return true;
}

static bool virtio_blk_pci_io_in(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
{
	unsigned long offset;
	bool ret = true;

	mutex_lock(&blk_device.mutex);

	offset		= port - IOPORT_VIRTIO_BLK;

	switch (offset) {
	case VIRTIO_PCI_HOST_FEATURES:
		ioport__write32(data, blk_device.host_features);
		break;
	case VIRTIO_PCI_GUEST_FEATURES:
		ret		= false;
		break;
	case VIRTIO_PCI_QUEUE_PFN:
		ioport__write32(data, blk_device.vqs[blk_device.queue_selector].pfn);
		break;
	case VIRTIO_PCI_QUEUE_NUM:
		ioport__write16(data, VIRTIO_BLK_QUEUE_SIZE);
		break;
	case VIRTIO_PCI_QUEUE_SEL:
	case VIRTIO_PCI_QUEUE_NOTIFY:
		ret		= false;
		break;
	case VIRTIO_PCI_STATUS:
		ioport__write8(data, blk_device.status);
		break;
	case VIRTIO_PCI_ISR:
		ioport__write8(data, 0x1);
		kvm__irq_line(self, VIRTIO_BLK_IRQ, 0);
		break;
	case VIRTIO_MSI_CONFIG_VECTOR:
		ioport__write16(data, blk_device.config_vector);
		break;
	default:
		ret		= virtio_blk_pci_io_device_specific_in(data, offset, size, count);
	};

	mutex_unlock(&blk_device.mutex);

	return ret;
}

static bool virtio_blk_do_io_request(struct kvm *self, struct virt_queue *queue)
{
	struct iovec iov[VIRTIO_BLK_QUEUE_SIZE];
	struct virtio_blk_outhdr *req;
	ssize_t block_cnt = -1;
	uint16_t out, in, head;
	uint8_t *status;

	head		= virt_queue__get_iov(queue, iov, &out, &in, self);

	/* head */
	req		= iov[0].iov_base;

	switch (req->type) {
	case VIRTIO_BLK_T_IN:
		block_cnt = disk_image__read_sector_iov(self->disk_image, req->sector, iov + 1, in + out - 2);

		break;
	case VIRTIO_BLK_T_OUT:
		block_cnt = disk_image__write_sector_iov(self->disk_image, req->sector, iov + 1, in + out - 2);

		break;

	default:
		warning("request type %d", req->type);
		block_cnt = -1;
	}

	/* status */
	status			= iov[out + in - 1].iov_base;
	*status			= (block_cnt < 0) ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK;

	virt_queue__set_used_elem(queue, head, block_cnt);

	return true;
}



static int virtio_blk_get_selected_queue(struct blk_device *dev)
{
	int i;

	for (i = 0 ; i < NUM_VIRT_QUEUES ; i++) {
		if (dev->virtio_blk_queue_set_flags & (1 << i)) {
			dev->virtio_blk_queue_set_flags &= ~(1 << i);
			return i;
		}
	}

	return -1;
}

static void virtio_blk_do_io(struct kvm *kvm, struct blk_device *dev)
{
	for (;;) {
		struct virt_queue *vq;
		int queue_index;

		mutex_lock(&dev->io_mutex);
		queue_index = virtio_blk_get_selected_queue(dev);
		mutex_unlock(&dev->io_mutex);

		if (queue_index < 0)
			break;

		vq = &dev->vqs[queue_index];

		while (virt_queue__available(vq))
			virtio_blk_do_io_request(kvm, vq);

		kvm__irq_line(kvm, VIRTIO_BLK_IRQ, 1);
	}
}

static void *virtio_blk_io_thread(void *ptr)
{
	struct kvm *self = ptr;

	for (;;) {
		int ret;

		mutex_lock(&blk_device.io_mutex);
		ret = pthread_cond_wait(&blk_device.io_cond, &blk_device.io_mutex);
		mutex_unlock(&blk_device.io_mutex);

		if (ret != 0)
			break;

		virtio_blk_do_io(self, &blk_device);
	}

	return NULL;
}

static void virtio_blk_handle_callback(struct blk_device *dev, uint16_t queue_index)
{
	mutex_lock(&dev->io_mutex);

	dev->virtio_blk_queue_set_flags |= (1 << queue_index);

	mutex_unlock(&dev->io_mutex);

	pthread_cond_signal(&dev->io_cond);
}

static bool virtio_blk_pci_io_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
{
	unsigned long offset;
	bool ret = true;

	mutex_lock(&blk_device.mutex);

	offset		= port - IOPORT_VIRTIO_BLK;

	switch (offset) {
	case VIRTIO_PCI_GUEST_FEATURES:
		blk_device.guest_features	= ioport__read32(data);
		break;
	case VIRTIO_PCI_QUEUE_PFN: {
		struct virt_queue *queue;
		void *p;

		queue			= &blk_device.vqs[blk_device.queue_selector];

		queue->pfn		= ioport__read32(data);

		p			= guest_flat_to_host(self, queue->pfn << 12);

		vring_init(&queue->vring, VIRTIO_BLK_QUEUE_SIZE, p, 4096);

		break;
	}
	case VIRTIO_PCI_QUEUE_SEL:
		blk_device.queue_selector	= ioport__read16(data);
		break;
	case VIRTIO_PCI_QUEUE_NOTIFY: {
		uint16_t queue_index;
		queue_index		= ioport__read16(data);
		virtio_blk_handle_callback(&blk_device, queue_index);
		break;
	}
	case VIRTIO_PCI_STATUS:
		blk_device.status		= ioport__read8(data);
		break;
	case VIRTIO_MSI_CONFIG_VECTOR:
		blk_device.config_vector	= VIRTIO_MSI_NO_VECTOR;
		break;
	case VIRTIO_MSI_QUEUE_VECTOR:
		break;
	default:
		ret		= false;
	};

	mutex_unlock(&blk_device.mutex);

	return ret;
}

static struct ioport_operations virtio_blk_io_ops = {
	.io_in		= virtio_blk_pci_io_in,
	.io_out		= virtio_blk_pci_io_out,
};

#define PCI_VENDOR_ID_REDHAT_QUMRANET		0x1af4
#define PCI_DEVICE_ID_VIRTIO_BLK		0x1001
#define PCI_SUBSYSTEM_VENDOR_ID_REDHAT_QUMRANET	0x1af4
#define PCI_SUBSYSTEM_ID_VIRTIO_BLK		0x0002

static struct pci_device_header virtio_blk_pci_device = {
	.vendor_id		= PCI_VENDOR_ID_REDHAT_QUMRANET,
	.device_id		= PCI_DEVICE_ID_VIRTIO_BLK,
	.header_type		= PCI_HEADER_TYPE_NORMAL,
	.revision_id		= 0,
	.class			= 0x010000,
	.subsys_vendor_id	= PCI_SUBSYSTEM_VENDOR_ID_REDHAT_QUMRANET,
	.subsys_id		= PCI_SUBSYSTEM_ID_VIRTIO_BLK,
	.bar[0]			= IOPORT_VIRTIO_BLK | PCI_BASE_ADDRESS_SPACE_IO,
	.irq_pin		= 1,
	.irq_line		= VIRTIO_BLK_IRQ,
};

#define PCI_VIRTIO_BLK_DEVNUM 1

void virtio_blk__init(struct kvm *self)
{
	if (!self->disk_image)
		return;

	pthread_create(&blk_device.io_thread, NULL, virtio_blk_io_thread, self);

	blk_device.blk_config.capacity = self->disk_image->size / SECTOR_SIZE;

	pci__register(&virtio_blk_pci_device, PCI_VIRTIO_BLK_DEVNUM);

	ioport__register(IOPORT_VIRTIO_BLK, &virtio_blk_io_ops, IOPORT_VIRTIO_BLK_SIZE);
}