/*
* Copyright (C) International Business Machines Corp., 2005
* Author(s): Anthony Liguori <aliguori@us.ibm.com>
*
* Copyright (C) Red Hat 2007
*
* Xen Console
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; under version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include <sys/select.h>
#include <termios.h>
#include "qapi/error.h"
#include "hw/hw.h"
#include "chardev/char-fe.h"
#include "hw/xen/xen_backend.h"
#include "qapi/error.h"
#include <xen/io/console.h>
struct buffer {
uint8_t *data;
size_t consumed;
size_t size;
size_t capacity;
size_t max_capacity;
};
struct XenConsole {
struct XenDevice xendev; /* must be first */
struct buffer buffer;
char console[XEN_BUFSIZE];
int ring_ref;
void *sring;
CharBackend chr;
int backlog;
};
static void buffer_append(struct XenConsole *con)
{
struct buffer *buffer = &con->buffer;
XENCONS_RING_IDX cons, prod, size;
struct xencons_interface *intf = con->sring;
cons = intf->out_cons;
prod = intf->out_prod;
xen_mb();
size = prod - cons;
if ((size == 0) || (size > sizeof(intf->out)))
return;
if ((buffer->capacity - buffer->size) < size) {
buffer->capacity += (size + 1024);
buffer->data = g_realloc(buffer->data, buffer->capacity);
}
while (cons != prod)
buffer->data[buffer->size++] = intf->out[
MASK_XENCONS_IDX(cons++, intf->out)];
xen_mb();
intf->out_cons = cons;
xen_pv_send_notify(&con->xendev);
if (buffer->max_capacity &&
buffer->size > buffer->max_capacity) {
/* Discard the middle of the data. */
size_t over = buffer->size - buffer->max_capacity;
uint8_t *maxpos = buffer->data + buffer->max_capacity;
memmove(maxpos - over, maxpos, over);
buffer->data = g_realloc(buffer->data, buffer->max_capacity);
buffer->size = buffer->capacity = buffer->max_capacity;
if (buffer->consumed > buffer->max_capacity - over)
buffer->consumed = buffer->max_capacity - over;
}
}
static void buffer_advance(struct buffer *buffer, size_t len)
{
buffer->consumed += len;
if (buffer->consumed == buffer->size) {
buffer->consumed = 0;
buffer->size = 0;
}
}
static int ring_free_bytes(struct XenConsole *con)
{
struct xencons_interface *intf = con->sring;
XENCONS_RING_IDX cons, prod, space;
cons = intf->in_cons;
prod = intf->in_prod;
xen_mb();
space = prod - cons;
if (space > sizeof(intf->in))
return 0; /* ring is screwed: ignore it */
return (sizeof(intf->in) - space);
}
static int xencons_can_receive(void *opaque)
{
struct XenConsole *con = opaque;
return ring_free_bytes(con);
}
static void xencons_receive(void *opaque, const uint8_t *buf, int len)
{
struct XenConsole *con = opaque;
struct xencons_interface *intf = con->sring;
XENCONS_RING_IDX prod;
int i, max;
max = ring_free_bytes(con);
/* The can_receive() func limits this, but check again anyway */
if (max < len)
len = max;
prod = intf->in_prod;
for (i = 0; i < len; i++) {
intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
buf[i];
}
xen_wmb();
intf->in_prod = prod;
xen_pv_send_notify(&con->xendev);
}
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 int con_init(struct XenDevice *xendev)
{
struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
char *type, *dom, label[32];
int ret = 0;
const char *output;
/* setup */
dom = xs_get_domain_path(xenstore, con->xendev.dom);
if (!xendev->dev) {
snprintf(con->console, sizeof(con->console), "%s/console", dom);
} else {
snprintf(con->console, sizeof(con->console), "%s/device/console/%d", dom, xendev->dev);
}
free(dom);
type = xenstore_read_str(con->console, "type");
if (!type || strcmp(type, "ioemu") != 0) {
xen_pv_printf(xendev, 1, "not for me (type=%s)\n", type);
ret = -1;
goto out;
}
output = xenstore_read_str(con->console, "output");
/* no Xen override, use qemu output device */
if (output == NULL) {
if (con->xendev.dev) {
qemu_chr_fe_init(&con->chr, serial_hds[con->xendev.dev],
&error_abort);
}
} else {
snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
qemu_chr_fe_init(&con->chr,
qemu_chr_new(label, output), &error_abort);
}
xenstore_store_pv_console_info(con->xendev.dev,
qemu_chr_fe_get_driver(&con->chr));
out:
g_free(type);
return ret;
}
static int con_initialise(struct XenDevice *xendev)
{
struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
int limit;
if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1)
return -1;
if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1)
return -1;
if (xenstore_read_int(con->console, "limit", &limit) == 0)
con->buffer.max_capacity = limit;
if (!xendev->dev) {
xen_pfn_t mfn = con->ring_ref;
con->sring = xenforeignmemory_map(xen_fmem, con->xendev.dom,
PROT_READ|PROT_WRITE,
1, &mfn, NULL);
} else {
con->sring = xengnttab_map_grant_ref(xendev->gnttabdev, con->xendev.dom,
con->ring_ref,
PROT_READ|PROT_WRITE);
}
if (!con->sring)
return -1;
xen_be_bind_evtchn(&con->xendev);
qemu_chr_fe_set_handlers(&con->chr, xencons_can_receive,
xencons_receive, NULL, NULL, con, NULL, true);
xen_pv_printf(xendev, 1,
"ring mfn %d, remote port %d, local port %d, limit %zd\n",
con->ring_ref,
con->xendev.remote_port,
con->xendev.local_port,
con->buffer.max_capacity);
return 0;
}
static void con_disconnect(struct XenDevice *xendev)
{
struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
qemu_chr_fe_deinit(&con->chr, false);
xen_pv_unbind_evtchn(&con->xendev);
if (con->sring) {
if (!xendev->dev) {
xenforeignmemory_unmap(xen_fmem, con->sring, 1);
} else {
xengnttab_unmap(xendev->gnttabdev, con->sring, 1);
}
con->sring = NULL;
}
}
static void con_event(struct XenDevice *xendev)
{
struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
buffer_append(con);
if (con->buffer.size - con->buffer.consumed)
xencons_send(con);
}
/* -------------------------------------------------------------------- */
struct XenDevOps xen_console_ops = {
.size = sizeof(struct XenConsole),
.flags = DEVOPS_FLAG_IGNORE_STATE|DEVOPS_FLAG_NEED_GNTDEV,
.init = con_init,
.initialise = con_initialise,
.event = con_event,
.disconnect = con_disconnect,
};
