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/*
* Virtio Console Device
*
* Copyright IBM, Corp. 2008
*
* Authors:
* Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "hw.h"
#include "qemu-char.h"
#include "virtio.h"
#include "virtio-console.h"
typedef struct VirtIOConsole
{
VirtIODevice vdev;
VirtQueue *ivq, *ovq;
CharDriverState *chr;
} VirtIOConsole;
static VirtIOConsole *to_virtio_console(VirtIODevice *vdev)
{
return (VirtIOConsole *)vdev;
}
static void virtio_console_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOConsole *s = to_virtio_console(vdev);
VirtQueueElement elem;
while (virtqueue_pop(vq, &elem)) {
ssize_t len = 0;
int d;
for (d = 0; d < elem.out_num; d++) {
len += qemu_chr_write(s->chr, (uint8_t *)elem.out_sg[d].iov_base,
elem.out_sg[d].iov_len);
}
virtqueue_push(vq, &elem, len);
virtio_notify(vdev, vq);
}
}
static void virtio_console_handle_input(VirtIODevice *vdev, VirtQueue *vq)
{
}
static uint32_t virtio_console_get_features(VirtIODevice *vdev)
{
return 0;
}
static int vcon_can_read(void *opaque)
{
VirtIOConsole *s = (VirtIOConsole *) opaque;
if (!virtio_queue_ready(s->ivq) ||
!(s->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
virtio_queue_empty(s->ivq))
return 0;
/* current implementations have a page sized buffer.
* We fall back to a one byte per read if there is not enough room.
* It would be cool to have a function that returns the available byte
* instead of checking for a limit */
if (virtqueue_avail_bytes(s->ivq, TARGET_PAGE_SIZE, 0))
return TARGET_PAGE_SIZE;
if (virtqueue_avail_bytes(s->ivq, 1, 0))
return 1;
return 0;
}
static void vcon_read(void *opaque, const uint8_t *buf, int size)
{
VirtIOConsole *s = (VirtIOConsole *) opaque;
VirtQueueElement elem;
int offset = 0;
/* The current kernel implementation has only one outstanding input
* buffer of PAGE_SIZE. Nevertheless, this function is prepared to
* handle multiple buffers with multiple sg element for input */
while (offset < size) {
int i = 0;
if (!virtqueue_pop(s->ivq, &elem))
break;
while (offset < size && i < elem.in_num) {
int len = MIN(elem.in_sg[i].iov_len, size - offset);
memcpy(elem.in_sg[i].iov_base, buf + offset, len);
offset += len;
i++;
}
virtqueue_push(s->ivq, &elem, size);
}
virtio_notify(&s->vdev, s->ivq);
}
static void vcon_event(void *opaque, int event)
{
/* we will ignore any event for the time being */
}
static void virtio_console_save(QEMUFile *f, void *opaque)
{
VirtIOConsole *s = opaque;
virtio_save(&s->vdev, f);
}
static int virtio_console_load(QEMUFile *f, void *opaque, int version_id)
{
VirtIOConsole *s = opaque;
if (version_id != 1)
return -EINVAL;
virtio_load(&s->vdev, f);
return 0;
}
VirtIODevice *virtio_console_init(DeviceState *dev)
{
VirtIOConsole *s;
s = (VirtIOConsole *)virtio_common_init("virtio-console",
VIRTIO_ID_CONSOLE,
0, sizeof(VirtIOConsole));
s->vdev.get_features = virtio_console_get_features;
s->ivq = virtio_add_queue(&s->vdev, 128, virtio_console_handle_input);
s->ovq = virtio_add_queue(&s->vdev, 128, virtio_console_handle_output);
s->chr = qdev_init_chardev(dev);
qemu_chr_add_handlers(s->chr, vcon_can_read, vcon_read, vcon_event, s);
register_savevm("virtio-console", -1, 1, virtio_console_save, virtio_console_load, s);
return &s->vdev;
}
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