path: root/drivers/s390/kvm/virtio_ccw.c

/*
 * ccw based virtio transport
 *
 * Copyright IBM Corp. 2012
 *
 * 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): Cornelia Huck <cornelia.huck@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/interrupt.h>
#include <linux/virtio_ring.h>
#include <linux/pfn.h>
#include <linux/async.h>
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/kvm_para.h>
#include <asm/setup.h>
#include <asm/irq.h>
#include <asm/cio.h>
#include <asm/ccwdev.h>
#include <asm/virtio-ccw.h>

/*
 * virtio related functions
 */

struct vq_config_block {
	__u16 index;
	__u16 num;
} __packed;

#define VIRTIO_CCW_CONFIG_SIZE 0x100
/* same as PCI config space size, should be enough for all drivers */

struct virtio_ccw_device {
	struct virtio_device vdev;
	__u8 *status;
	__u8 config[VIRTIO_CCW_CONFIG_SIZE];
	struct ccw_device *cdev;
	__u32 curr_io;
	int err;
	wait_queue_head_t wait_q;
	spinlock_t lock;
	struct list_head virtqueues;
	unsigned long indicators;
	unsigned long indicators2;
	struct vq_config_block *config_block;
};

struct vq_info_block {
	__u64 queue;
	__u32 align;
	__u16 index;
	__u16 num;
} __packed;

struct virtio_feature_desc {
	__u32 features;
	__u8 index;
} __packed;

struct virtio_ccw_vq_info {
	struct virtqueue *vq;
	int num;
	void *queue;
	struct vq_info_block *info_block;
	struct list_head node;
	long cookie;
};

#define CCW_CMD_SET_VQ 0x13
#define CCW_CMD_VDEV_RESET 0x33
#define CCW_CMD_SET_IND 0x43
#define CCW_CMD_SET_CONF_IND 0x53
#define CCW_CMD_READ_FEAT 0x12
#define CCW_CMD_WRITE_FEAT 0x11
#define CCW_CMD_READ_CONF 0x22
#define CCW_CMD_WRITE_CONF 0x21
#define CCW_CMD_WRITE_STATUS 0x31
#define CCW_CMD_READ_VQ_CONF 0x32

#define VIRTIO_CCW_DOING_SET_VQ 0x00010000
#define VIRTIO_CCW_DOING_RESET 0x00040000
#define VIRTIO_CCW_DOING_READ_FEAT 0x00080000
#define VIRTIO_CCW_DOING_WRITE_FEAT 0x00100000
#define VIRTIO_CCW_DOING_READ_CONFIG 0x00200000
#define VIRTIO_CCW_DOING_WRITE_CONFIG 0x00400000
#define VIRTIO_CCW_DOING_WRITE_STATUS 0x00800000
#define VIRTIO_CCW_DOING_SET_IND 0x01000000
#define VIRTIO_CCW_DOING_READ_VQ_CONF 0x02000000
#define VIRTIO_CCW_DOING_SET_CONF_IND 0x04000000
#define VIRTIO_CCW_INTPARM_MASK 0xffff0000

static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
{
	return container_of(vdev, struct virtio_ccw_device, vdev);
}

static int doing_io(struct virtio_ccw_device *vcdev, __u32 flag)
{
	unsigned long flags;
	__u32 ret;

	spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
	if (vcdev->err)
		ret = 0;
	else
		ret = vcdev->curr_io & flag;
	spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
	return ret;
}

static int ccw_io_helper(struct virtio_ccw_device *vcdev,
			 struct ccw1 *ccw, __u32 intparm)
{
	int ret;
	unsigned long flags;
	int flag = intparm & VIRTIO_CCW_INTPARM_MASK;

	do {
		spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
		ret = ccw_device_start(vcdev->cdev, ccw, intparm, 0, 0);
		if (!ret) {
			if (!vcdev->curr_io)
				vcdev->err = 0;
			vcdev->curr_io |= flag;
		}
		spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
		cpu_relax();
	} while (ret == -EBUSY);
	wait_event(vcdev->wait_q, doing_io(vcdev, flag) == 0);
	return ret ? ret : vcdev->err;
}

static inline long do_kvm_notify(struct subchannel_id schid,
				 unsigned long queue_index,
				 long cookie)
{
	register unsigned long __nr asm("1") = KVM_S390_VIRTIO_CCW_NOTIFY;
	register struct subchannel_id __schid asm("2") = schid;
	register unsigned long __index asm("3") = queue_index;
	register long __rc asm("2");
	register long __cookie asm("4") = cookie;

	asm volatile ("diag 2,4,0x500\n"
		      : "=d" (__rc) : "d" (__nr), "d" (__schid), "d" (__index),
		      "d"(__cookie)
		      : "memory", "cc");
	return __rc;
}

static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
{
	struct virtio_ccw_vq_info *info = vq->priv;
	struct virtio_ccw_device *vcdev;
	struct subchannel_id schid;

	vcdev = to_vc_device(info->vq->vdev);
	ccw_device_get_schid(vcdev->cdev, &schid);
	info->cookie = do_kvm_notify(schid, vq->index, info->cookie);
	if (info->cookie <</