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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 <cpu.h>
#include <helpers.h>
#include <byteorder.h>
#include "virtio.h"
#include "virtio-blk.h"
#include "virtio-internal.h"
#define DEFAULT_SECTOR_SIZE 512
#define DRIVER_FEATURE_SUPPORT (VIRTIO_BLK_F_BLK_SIZE | VIRTIO_F_VERSION_1)
static struct vqs vq;
/**
* Initialize virtio-block device.
* @param dev pointer to virtio device information
*/
int
virtioblk_init(struct virtio_device *dev)
{
struct vring_avail *vq_avail;
int blk_size = DEFAULT_SECTOR_SIZE;
uint64_t features;
int status = VIRTIO_STAT_ACKNOWLEDGE;
/* Reset device */
virtio_reset_device(dev);
/* Acknowledge device. */
virtio_set_status(dev, status);
/* Tell HV that we know how to drive the device. */
status |= VIRTIO_STAT_DRIVER;
virtio_set_status(dev, status);
if (dev->is_modern) {
/* Negotiate features and sets FEATURES_OK if successful */
if (virtio_negotiate_guest_features(dev, DRIVER_FEATURE_SUPPORT))
goto dev_error;
virtio_get_status(dev, &status);
} else {
/* Device specific setup - we support F_BLK_SIZE */
virtio_set_guest_features(dev, VIRTIO_BLK_F_BLK_SIZE);
}
if (virtio_queue_init_vq(dev, &vq, 0))
goto dev_error;
vq_avail = virtio_get_vring_avail(dev, 0);
vq_avail->flags = virtio_cpu_to_modern16(dev, VRING_AVAIL_F_NO_INTERRUPT);
vq_avail->idx = 0;
/* Tell HV that setup succeeded */
status |= VIRTIO_STAT_DRIVER_OK;
virtio_set_status(dev, status);
features = virtio_get_host_features(dev);
if (features & VIRTIO_BLK_F_BLK_SIZE) {
blk_size = virtio_get_config(dev,
offset_of(struct virtio_blk_cfg, blk_size),
sizeof(blk_size));
}
return blk_size;
dev_error:
printf("%s: failed\n", __func__);
status |= VIRTIO_STAT_FAILED;
virtio_set_status(dev, status);
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);
}
static void fill_blk_hdr(struct virtio_blk_req *blkhdr, bool is_modern,
uint32_t type, uint32_t ioprio, uint32_t sector)
{
if (is_modern) {
blkhdr->type = cpu_to_le32(type);
blkhdr->ioprio = cpu_to_le32(ioprio);
blkhdr->sector = cpu_to_le64(sector);
} else {
blkhdr->type = type;
blkhdr->ioprio = ioprio;
blkhdr->sector = sector;
}
}
/**
* 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, uint64_t blocknum, long cnt)
{
struct vring_desc *desc;
int id;
static struct virtio_blk_req blkhdr;
//struct virtio_blk_config *blkconf;
uint64_t capacity;
uint32_t vq_size, time;
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, avail_idx;
int blk_size = DEFAULT_SECTOR_SIZE;
//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,
offset_of(struct virtio_blk_cfg, capacity),
sizeof(capacity));
if (blocknum + cnt - 1 > capacity) {
puts("virtioblk_read: Access beyond end of device!");
return 0;
}
blk_size = virtio_get_config(dev,
offset_of(struct virtio_blk_cfg, blk_size),
sizeof(blk_size));
if (blk_size % DEFAULT_SECTOR_SIZE) {
fprintf(stderr, "virtio-blk: Unaligned sector read %d\n", blk_size);
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);
avail_idx = virtio_modern16_to_cpu(dev, vq_avail->idx);
last_used_idx = vq_used->idx;
current_used_idx = &vq_used->idx;
/* Set up header */
fill_blk_hdr(&blkhdr, dev->is_modern, VIRTIO_BLK_T_IN | VIRTIO_BLK_T_BARRIER,
1, blocknum * blk_size / DEFAULT_SECTOR_SIZE);
/* Determine descriptor index */
id = (avail_idx * 3) % vq_size;
/* Set up virtqueue descriptor for header */
desc = &vq_desc[id];
virtio_fill_desc(desc, dev->is_modern, (uint64_t)&blkhdr,
sizeof(struct virtio_blk_req),
VRING_DESC_F_NEXT, (id + 1) % vq_size);
/* Set up virtqueue descriptor for data */
desc = &vq_desc[(id + 1) % vq_size];
virtio_fill_desc(desc, dev->is_modern, (uint64_t)buf, cnt * blk_size,
VRING_DESC_F_NEXT | VRING_DESC_F_WRITE,
(id + 2) % vq_size);
/* Set up virtqueue descriptor for status */
desc = &vq_desc[(id + 2) % vq_size];
virtio_fill_desc(desc, dev->is_modern, (uint64_t)&status, 1,
VRING_DESC_F_WRITE, 0);
vq_avail->ring[avail_idx % vq_size] = virtio_cpu_to_modern16 (dev, id);
mb();
vq_avail->idx = virtio_cpu_to_modern16(dev, avail_idx + 1);
/* Tell HV that the queue is ready */
virtio_queue_notify(dev, 0);
/* Wait for host to consume the descriptor */
time = SLOF_GetTimer() + VIRTIO_TIMEOUT;
while (*current_used_idx == last_used_idx) {
// do something better
mb();
if (time < SLOF_GetTimer())
break;
}
if (status == 0)
return cnt;
printf("virtioblk_read failed! status = %i\n", status);
return 0;
}
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