#include "kvm/virtio-scsi.h"
#include "kvm/virtio-pci-dev.h"
#include "kvm/disk-image.h"
#include "kvm/irq.h"
#include "kvm/kvm.h"
#include "kvm/pci.h"
#include "kvm/ioeventfd.h"
#include "kvm/guest_compat.h"
#include "kvm/virtio-pci.h"
#include "kvm/virtio.h"
#include "kvm/strbuf.h"

#include <linux/kernel.h>
#include <linux/virtio_scsi.h>
#include <linux/vhost.h>

#define VIRTIO_SCSI_QUEUE_SIZE		128
#define NUM_VIRT_QUEUES			3

static LIST_HEAD(sdevs);
static int compat_id = -1;

struct scsi_dev {
	struct virt_queue		vqs[NUM_VIRT_QUEUES];
	struct virtio_scsi_config	config;
	struct vhost_scsi_target	target;
	int				vhost_fd;
	struct virtio_device		vdev;
	struct list_head		list;
	struct kvm			*kvm;
};

static u8 *get_config(struct kvm *kvm, void *dev)
{
	struct scsi_dev *sdev = dev;

	return ((u8 *)(&sdev->config));
}

static size_t get_config_size(struct kvm *kvm, void *dev)
{
	struct scsi_dev *sdev = dev;

	return sizeof(sdev->config);
}

static u64 get_host_features(struct kvm *kvm, void *dev)
{
	int r;
	u64 features;
	struct scsi_dev *sdev = dev;

	r = ioctl(sdev->vhost_fd, VHOST_GET_FEATURES, &features);
	if (r != 0)
		die_perror("VHOST_GET_FEATURES failed");

	return features &
		(1ULL << VIRTIO_RING_F_EVENT_IDX |	\
		 1ULL << VIRTIO_RING_F_INDIRECT_DESC |	\
		 1ULL << VIRTIO_F_ANY_LAYOUT);
}

static void notify_status(struct kvm *kvm, void *dev, u32 status)
{
	int r;
	struct scsi_dev *sdev = dev;
	struct virtio_device *vdev = &sdev->vdev;
	struct virtio_scsi_config *conf = &sdev->config;
	u16 endian = vdev->endian;

	if (status & VIRTIO__STATUS_START) {
		r = virtio_vhost_set_features(sdev->vhost_fd, sdev->vdev.features);
		if (r != 0)
			die_perror("VHOST_SET_FEATURES failed");

		r = ioctl(sdev->vhost_fd, VHOST_SCSI_SET_ENDPOINT,
			      &sdev->target);
		if (r != 0)
			die("VHOST_SCSI_SET_ENDPOINT failed %d", errno);
	}

	if (!(status & VIRTIO__STATUS_CONFIG))
		return;

	conf->num_queues = virtio_host_to_guest_u32(endian, NUM_VIRT_QUEUES - 2);
	conf->seg_max = virtio_host_to_guest_u32(endian, VIRTIO_SCSI_CDB_SIZE - 2);
	conf->max_sectors = virtio_host_to_guest_u32(endian, 65535);
	conf->cmd_per_lun = virtio_host_to_guest_u32(endian, 128);
	conf->sense_size = virtio_host_to_guest_u32(endian, VIRTIO_SCSI_SENSE_SIZE);
	conf->cdb_size = virtio_host_to_guest_u32(endian, VIRTIO_SCSI_CDB_SIZE);
	conf->max_target = virtio_host_to_guest_u16(endian, 255);
	conf->max_lun = virtio_host_to_guest_u32(endian, 16383);
	conf->event_info_size = virtio_host_to_guest_u32(endian, sizeof(struct virtio_scsi_event));
}

static int init_vq(struct kvm *kvm, void *dev, u32 vq)
{
	struct scsi_dev *sdev = dev;
	struct virt_queue *queue;

	compat__remove_message(compat_id);

	queue		= &sdev->vqs[vq];

	virtio_init_device_vq(kvm, &sdev->vdev, queue, VIRTIO_SCSI_QUEUE_SIZE);

	if (sdev->vhost_fd == 0)
		return 0;

	virtio_vhost_set_vring(kvm, sdev->vhost_fd, vq, queue);
	return 0;
}

static void notify_vq_gsi(struct kvm *kvm, void *dev, u32 vq, u32 gsi)
{
	struct scsi_dev *sdev = dev;

	if (sdev->vhost_fd == 0)
		return;

	virtio_vhost_set_vring_irqfd(kvm, gsi, &sdev->vqs[vq]);
}

static void notify_vq_eventfd(struct kvm *kvm, void *dev, u32 vq, u32 efd)
{
	struct scsi_dev *sdev = dev;

	if (sdev->vhost_fd == 0)
		return;

	virtio_vhost_set_vring_kick(kvm, sdev->vhost_fd, vq, efd);
}

static int notify_vq(struct kvm *kvm, void *dev, u32 vq)
{
	return 0;
}

static struct virt_queue *get_vq(struct kvm *kvm, void *dev, u32 vq)
{
	struct scsi_dev *sdev = dev;

	return &sdev->vqs[vq];
}

static int get_size_vq(struct kvm *kvm, void *dev, u32 vq)
{
	return VIRTIO_SCSI_QUEUE_SIZE;
}

static int set_size_vq(struct kvm *kvm, void *dev, u32 vq, int size)
{
	return size;
}

static unsigned int get_vq_count(struct kvm *kvm, void *dev)
{
	return NUM_VIRT_QUEUES;
}

static struct virtio_ops scsi_dev_virtio_ops = {
	.get_config		= get_config,
	.get_config_size	= get_config_size,
	.get_host_features	= get_host_features,
	.init_vq		= init_vq,
	.get_vq			= get_vq,
	.get_size_vq		= get_size_vq,
	.set_size_vq		= set_size_vq,
	.notify_status		= notify_status,
	.notify_vq		= notify_vq,
	.notify_vq_gsi		= notify_vq_gsi,
	.notify_vq_eventfd	= notify_vq_eventfd,
	.get_vq_count		= get_vq_count,
};

static void virtio_scsi_vhost_init(struct kvm *kvm, struct scsi_dev *sdev)
{
	sdev->vhost_fd = open("/dev/vhost-scsi", O_RDWR);
	if (sdev->vhost_fd < 0)
		die_perror("Failed openning vhost-scsi device");

	virtio_vhost_init(kvm, sdev->vhost_fd);

	sdev->vdev.use_vhost = true;
}


static int virtio_scsi_init_one(struct kvm *kvm, struct disk_image *disk)
{
	struct scsi_dev *sdev;
	int r;

	if (!disk)
		return -EINVAL;

	sdev = calloc(1, sizeof(struct scsi_dev));
	if (sdev == NULL)
		return -ENOMEM;

	*sdev = (struct scsi_dev) {
		.kvm			= kvm,
	};
	strlcpy((char *)&sdev->target.vhost_wwpn, disk->wwpn, sizeof(sdev->target.vhost_wwpn));
	sdev->target.abi_version = VHOST_SCSI_ABI_VERSION;

	list_add_tail(&sdev->list, &sdevs);

	r = virtio_init(kvm, sdev, &sdev->vdev, &scsi_dev_virtio_ops,
			kvm->cfg.virtio_transport, PCI_DEVICE_ID_VIRTIO_SCSI,
			VIRTIO_ID_SCSI, PCI_CLASS_BLK);
	if (r < 0)
		return r;

	virtio_scsi_vhost_init(kvm, sdev);

	if (compat_id == -1)
		compat_id = virtio_compat_add_message("virtio-scsi", "CONFIG_SCSI_VIRTIO");

	return 0;
}

static int virtio_scsi_exit_one(struct kvm *kvm, struct scsi_dev *sdev)
{
	int r;

	r = ioctl(sdev->vhost_fd, VHOST_SCSI_CLEAR_ENDPOINT, &sdev->target);
	if (r != 0)
		die("VHOST_SCSI_CLEAR_ENDPOINT failed %d", errno);

	list_del(&sdev->list);
	free(sdev);

	return 0;
}

int virtio_scsi_init(struct kvm *kvm)
{
	int i, r = 0;

	for (i = 0; i < kvm->nr_disks; i++) {
		if (!kvm->disks[i]->wwpn)
			continue;
		r = virtio_scsi_init_one(kvm, kvm->disks[i]);
		if (r < 0)
			goto cleanup;
	}

	return 0;
cleanup:
	virtio_scsi_exit(kvm);
	return r;
}
virtio_dev_init(virtio_scsi_init);

int virtio_scsi_exit(struct kvm *kvm)
{
	while (!list_empty(&sdevs)) {
		struct scsi_dev *sdev;

		sdev = list_first_entry(&sdevs, struct scsi_dev, list);
		virtio_scsi_exit_one(kvm, sdev);
	}

	return 0;
}
virtio_dev_exit(virtio_scsi_exit);