static void xencons_send(struct XenConsole *con)
{
ssize_t len, size;
size = con->buffer.size - con->buffer.consumed;
if (qemu_chr_fe_backend_connected(&con->chr)) {
len = qemu_chr_fe_write(&con->chr,
con->buffer.data + con->buffer.consumed,
size);
} else {
len = size;
}
if (len < 1) {
if (!con->backlog) {
con->backlog = 1;
xen_pv_printf(&con->xendev, 1,
"backlog piling up, nobody listening?\n");
}
} else {
buffer_advance(&con->buffer, len);
if (con->backlog && len == size) {
con->backlog = 0;
xen_pv_printf(&con->xendev, 1, "backlog is gone\n");
}
}
}
static void virtconsole_realize(DeviceState *dev, Error **errp)
{
VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
VirtConsole *vcon = VIRTIO_CONSOLE(dev);
VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(dev);
if (port->id == 0 && !k->is_console) {
error_setg(errp, "Port number 0 on virtio-serial devices reserved "
"for virtconsole devices for backward compatibility.");
return;
}
if (qemu_chr_fe_backend_connected(&vcon->chr)) {
/*
* For consoles we don't block guest data transfer just
* because nothing is connected - we'll just let it go
* whetherever the chardev wants - /dev/null probably.
*
* For serial ports we need 100% reliable data transfer
* so we use the opened/closed signals from chardev to
* trigger open/close of the device
*/
if (k->is_console) {
qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
NULL, chr_be_change,
vcon, NULL, true);
virtio_serial_open(port);
} else {
qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
chr_event, chr_be_change,
vcon, NULL, false);
}
}
}
/* Callback function that's called when the guest sends us data */
static ssize_t flush_buf(VirtIOSerialPort *port,
const uint8_t *buf, ssize_t len)
{
VirtConsole *vcon = VIRTIO_CONSOLE(port);
ssize_t ret;
if (!qemu_chr_fe_backend_connected(&vcon->chr)) {
/* If there's no backend, we can just say we consumed all data. */
return len;
}
ret = qemu_chr_fe_write(&vcon->chr, buf, len);
trace_virtio_console_flush_buf(port->id, len, ret);
if (ret < len) {
VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
/*
* Ideally we'd get a better error code than just -1, but
* that's what the chardev interface gives us right now. If
* we had a finer-grained message, like -EPIPE, we could close
* this connection.
*/
if (ret < 0)
ret = 0;
/* XXX we should be queuing data to send later for the
* console devices too rather than silently dropping
* console data on EAGAIN. The Linux virtio-console
* hvc driver though does sends with spinlocks held,
* so if we enable throttling that'll stall the entire
* guest kernel, not merely the process writing to the
* console.
*
* While we could queue data for later write without
* enabling throttling, this would result in the guest
* being able to trigger arbitrary memory usage in QEMU
* buffering data for later writes.
*
* So fixing this problem likely requires fixing the
* Linux virtio-console hvc driver to not hold spinlocks
* while writing, and instead merely block the process
* that's writing. QEMU would then need some way to detect
* if the guest had the fixed driver too, before we can
* use throttling on host side.
*/
if (!k->is_console) {
virtio_serial_throttle_port(port, true);
if (!vcon->watch) {
vcon->watch = qemu_chr_fe_add_watch(&vcon->chr,
G_IO_OUT|G_IO_HUP,
chr_write_unblocked, vcon);
}
}
}
return ret;
}
static void ipmi_bmc_extern_realize(DeviceState *dev, Error **errp)
{
IPMIBmcExtern *ibe = IPMI_BMC_EXTERN(dev);
if (!qemu_chr_fe_backend_connected(&ibe->chr)) {
error_setg(errp, "IPMI external bmc requires chardev attribute");
return;
}
qemu_chr_fe_set_handlers(&ibe->chr, can_receive, receive,
chr_event, NULL, ibe, NULL, true);
}
/*
* Triggered by SCLP's write_event_data
* - write console data to character layer
* returns < 0 if an error occurred
*/
static int write_console_data(SCLPEvent *event, const uint8_t *buf, int len)
{
SCLPConsoleLM *scon = SCLPLM_CONSOLE(event);
if (!qemu_chr_fe_backend_connected(&scon->chr)) {
/* If there's no backend, we can just say we consumed all data. */
return len;
}
/* XXX this blocks entire thread. Rewrite to use
* qemu_chr_fe_write and background I/O callbacks */
return qemu_chr_fe_write_all(&scon->chr, buf, len);
}
static void virtconsole_enable_backend(VirtIOSerialPort *port, bool enable)
{
VirtConsole *vcon = VIRTIO_CONSOLE(port);
if (!qemu_chr_fe_backend_connected(&vcon->chr)) {
return;
}
if (enable) {
VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
k->is_console ? NULL : chr_event,
chr_be_change, vcon, NULL, false);
} else {
qemu_chr_fe_set_handlers(&vcon->chr, NULL, NULL, NULL,
NULL, NULL, NULL, false);
}
}
static int mad_init(RdmaBackendDev *backend_dev, CharBackend *mad_chr_be)
{
int ret;
backend_dev->rdmacm_mux.chr_be = mad_chr_be;
ret = qemu_chr_fe_backend_connected(backend_dev->rdmacm_mux.chr_be);
if (!ret) {
rdma_error_report("Missing chardev for MAD multiplexer");
return -EIO;
}
rdma_protected_qlist_init(&backend_dev->recv_mads_list);
enable_rdmacm_mux_async(backend_dev);
qemu_chr_fe_set_handlers(backend_dev->rdmacm_mux.chr_be,
rdmacm_mux_can_receive, rdmacm_mux_read, NULL,
NULL, backend_dev, NULL, true);
return 0;
}
static void sh_serial_write(void *opaque, hwaddr offs,
uint64_t val, unsigned size)
{
sh_serial_state *s = opaque;
unsigned char ch;
#ifdef DEBUG_SERIAL
printf("sh_serial: write offs=0x%02x val=0x%02x\n",
offs, val);
#endif
switch(offs) {
case 0x00: /* SMR */
s->smr = val & ((s->feat & SH_SERIAL_FEAT_SCIF) ? 0x7b : 0xff);
return;
case 0x04: /* BRR */
s->brr = val;
return;
case 0x08: /* SCR */
/* TODO : For SH7751, SCIF mask should be 0xfb. */
s->scr = val & ((s->feat & SH_SERIAL_FEAT_SCIF) ? 0xfa : 0xff);
if (!(val & (1 << 5)))
s->flags |= SH_SERIAL_FLAG_TEND;
if ((s->feat & SH_SERIAL_FEAT_SCIF) && s->txi) {
qemu_set_irq(s->txi, val & (1 << 7));
}
if (!(val & (1 << 6))) {
qemu_set_irq(s->rxi, 0);
}
return;
case 0x0c: /* FTDR / TDR */
if (qemu_chr_fe_backend_connected(&s->chr)) {
ch = val;
/* XXX this blocks entire thread. Rewrite to use
* qemu_chr_fe_write and background I/O callbacks */
qemu_chr_fe_write_all(&s->chr, &ch, 1);
}
s->dr = val;
s->flags &= ~SH_SERIAL_FLAG_TDE;
return;
#if 0
case 0x14: /* FRDR / RDR */
ret = 0;
break;
#endif
}
if (s->feat & SH_SERIAL_FEAT_SCIF) {
switch(offs) {
case 0x10: /* FSR */
if (!(val & (1 << 6)))
s->flags &= ~SH_SERIAL_FLAG_TEND;
if (!(val & (1 << 5)))
s->flags &= ~SH_SERIAL_FLAG_TDE;
if (!(val & (1 << 4)))
s->flags &= ~SH_SERIAL_FLAG_BRK;
if (!(val & (1 << 1)))
s->flags &= ~SH_SERIAL_FLAG_RDF;
if (!(val & (1 << 0)))
s->flags &= ~SH_SERIAL_FLAG_DR;
if (!(val & (1 << 1)) || !(val & (1 << 0))) {
if (s->rxi) {
qemu_set_irq(s->rxi, 0);
}
}
return;
case 0x18: /* FCR */
s->fcr = val;
switch ((val >> 6) & 3) {
case 0:
s->rtrg = 1;
break;
case 1:
s->rtrg = 4;
break;
case 2:
s->rtrg = 8;
break;
case 3:
s->rtrg = 14;
break;
}
if (val & (1 << 1)) {
sh_serial_clear_fifo(s);
s->sr &= ~(1 << 1);
}
return;
case 0x20: /* SPTR */
s->sptr = val & 0xf3;
return;
case 0x24: /* LSR */
return;
}
}
else {
switch(offs) {
