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/******************************************************************************
* Copyright (c) 2011 IBM Corporation
* All rights reserved.
* This program and the accompanying materials
* are made available under the terms of the BSD License
* which accompanies this distribution, and is available at
* http://www.opensource.org/licenses/bsd-license.php
*
* Contributors:
* IBM Corporation - initial implementation
*****************************************************************************/
#include <stdio.h>
#include "virtio.h"
#include "virtio-blk.h"
#include "libhvcall.h"
#define sync() asm volatile (" sync \n" ::: "memory")
/**
* Initialize virtio-block device.
* @param dev pointer to virtio device information
*/
int
virtioblk_init(struct virtio_device *dev)
{
struct vring_avail *vq_avail;
/* Reset device */
// virtio_reset_device(dev);
/* Acknowledge device. */
virtio_set_status(dev, VIRTIO_STAT_ACKNOWLEDGE);
/* Tell HV that we know how to drive the device. */
virtio_set_status(dev, VIRTIO_STAT_ACKNOWLEDGE|VIRTIO_STAT_DRIVER);
/* Device specific setup - we do not support special features right now */
virtio_set_guest_features(dev, 0);
vq_avail = virtio_get_vring_avail(dev, 0);
vq_avail->flags = VRING_AVAIL_F_NO_INTERRUPT;
vq_avail->idx = 0;
/* Tell HV that setup succeeded */
virtio_set_status(dev, VIRTIO_STAT_ACKNOWLEDGE|VIRTIO_STAT_DRIVER
|VIRTIO_STAT_DRIVER_OK);
return 0;
}
/**
* Shutdown the virtio-block device.
* @param dev pointer to virtio device information
*/
void
virtioblk_shutdown(struct virtio_device *dev)
{
/* Quiesce device */
virtio_set_status(dev, VIRTIO_STAT_FAILED);
/* Reset device */
virtio_reset_device(dev);
}
/**
* Read blocks
* @param reg pointer to "reg" property
* @param buf pointer to destination buffer
* @param blocknum block number of the first block that should be read
* @param cnt amount of blocks that should be read
* @return number of blocks that have been read successfully
*/
int
virtioblk_read(struct virtio_device *dev, char *buf, long blocknum, long cnt)
{
struct vring_desc *desc;
int id, i;
static struct virtio_blk_req blkhdr;
//struct virtio_blk_config *blkconf;
uint64_t capacity;
uint32_t vq_size;
struct vring_desc *vq_desc; /* Descriptor vring */
struct vring_avail *vq_avail; /* "Available" vring */
struct vring_used *vq_used; /* "Used" vring */
volatile uint8_t status = -1;
volatile uint16_t *current_used_idx;
uint16_t last_used_idx;
//printf("virtioblk_read: dev=%p buf=%p blocknum=%li count=%li\n",
// dev, buf, blocknum, cnt);
/* Check whether request is within disk capacity */
capacity = virtio_get_config(dev, 0, sizeof(capacity));
if (blocknum + cnt - 1 > capacity) {
puts("virtioblk_read: Access beyond end of device!");
return 0;
}
vq_size = virtio_get_qsize(dev, 0);
vq_desc = virtio_get_vring_desc(dev, 0);
vq_avail = virtio_get_vring_avail(dev, 0);
vq_used = virtio_get_vring_used(dev, 0);
last_used_idx = vq_used->idx;
current_used_idx = &vq_used->idx;
/* Set up header */
blkhdr.type = VIRTIO_BLK_T_IN | VIRTIO_BLK_T_BARRIER;
blkhdr.ioprio = 1;
blkhdr.sector = blocknum;
/* Determine descriptor index */
id = (vq_avail->idx * 3) % vq_size;
/* Set up virtqueue descriptor for header */
desc = &vq_desc[id];
desc->addr = (uint64_t)&blkhdr;
desc->len = sizeof(struct virtio_blk_req);
desc->flags = VRING_DESC_F_NEXT;
desc->next = (id + 1) % vq_size;
/* Set up virtqueue descriptor for data */
desc = &vq_desc[(id + 1) % vq_size];
desc->addr = (uint64_t)buf;
desc->len = cnt * 512;
desc->flags = VRING_DESC_F_NEXT | VRING_DESC_F_WRITE;
desc->next = (id + 2) % vq_size;
/* Set up virtqueue descriptor for status */
desc = &vq_desc[(id + 2) % vq_size];
desc->addr = (uint64_t)&status;
desc->len = 1;
desc->flags = VRING_DESC_F_WRITE;
desc->next = 0;
vq_avail->ring[vq_avail->idx % vq_size] = id;
sync();
vq_avail->idx += 1;
/* Tell HV that the queue is ready */
virtio_queue_notify(dev, 0);
/* Wait for host to consume the descriptor */
i = 10000000;
while (*current_used_idx == last_used_idx && i-- > 0) {
sync();
}
if (status == 0)
return cnt;
printf("virtioblk_read failed! status = %i\n", status);
return 0;
}
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