virtio-serial: Apps should consume all data that guest sends out / Fix virtio api abuse

We cannot indicate to the guest how much data was consumed by an app for
out_bufs.  So we just have to assume the apps will consume all the data
that are handed over to them.

Fix the virtio api abuse in control_out() and handle_output().

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Amit Shah 2010-04-27 18:04:09 +05:30 committed by Anthony Liguori
parent e85ba9b2dc
commit 1e4476aa03
3 changed files with 8 additions and 11 deletions

View File

@ -20,14 +20,11 @@ typedef struct VirtConsole {
/* Callback function that's called when the guest sends us data */
static size_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
static void flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
{
VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
ssize_t ret;
ret = qemu_chr_write(vcon->chr, buf, len);
return ret < 0 ? 0 : ret;
qemu_chr_write(vcon->chr, buf, len);
}
/* Readiness of the guest to accept data on a port */

View File

@ -335,7 +335,7 @@ static void control_out(VirtIODevice *vdev, VirtQueue *vq)
copied = iov_to_buf(elem.out_sg, elem.out_num, buf, 0, len);
handle_control_message(vser, buf, copied);
virtqueue_push(vq, &elem, copied);
virtqueue_push(vq, &elem, 0);
}
qemu_free(buf);
virtio_notify(vdev, vq);
@ -379,11 +379,11 @@ static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
buf = qemu_malloc(buf_size);
ret = iov_to_buf(elem.out_sg, elem.out_num, buf, 0, buf_size);
ret = port->info->have_data(port, buf, ret);
port->info->have_data(port, buf, ret);
qemu_free(buf);
next_buf:
virtqueue_push(vq, &elem, ret);
virtqueue_push(vq, &elem, 0);
}
virtio_notify(vdev, vq);
}

View File

@ -136,10 +136,10 @@ struct VirtIOSerialPortInfo {
/*
* Guest wrote some data to the port. This data is handed over to
* the app via this callback. The app should return the number of
* bytes it successfully consumed.
* the app via this callback. The app is supposed to consume all
* the data that is presented to it.
*/
size_t (*have_data)(VirtIOSerialPort *port, const uint8_t *buf, size_t len);
void (*have_data)(VirtIOSerialPort *port, const uint8_t *buf, size_t len);
};
/* Interface to the virtio-serial bus */