The new xen_console protocol changed the default xen_console output device from whatever Qemu chose to whatever xenstore choses and "pty" as fallback. This is not how Qemu works. It has its own serial redirection semantics. So it xenstore doesn't contain information on what to do, Qemu is the place to ask. Signed-off-by: Alexander Graf <agraf@suse.de>
280 lines
7.3 KiB
C
280 lines
7.3 KiB
C
/*
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* Copyright (C) International Business Machines Corp., 2005
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* Author(s): Anthony Liguori <aliguori@us.ibm.com>
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*
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* Copyright (C) Red Hat 2007
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*
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* Xen Console
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; under version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include <sys/select.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <termios.h>
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#include <stdarg.h>
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#include <sys/mman.h>
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#include <xs.h>
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#include <xen/io/console.h>
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#include <xenctrl.h>
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#include "hw.h"
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#include "qemu-char.h"
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#include "xen_backend.h"
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struct buffer {
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uint8_t *data;
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size_t consumed;
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size_t size;
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size_t capacity;
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size_t max_capacity;
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};
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struct XenConsole {
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struct XenDevice xendev; /* must be first */
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struct buffer buffer;
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char console[XEN_BUFSIZE];
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int ring_ref;
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void *sring;
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CharDriverState *chr;
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int backlog;
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};
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static void buffer_append(struct XenConsole *con)
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{
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struct buffer *buffer = &con->buffer;
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XENCONS_RING_IDX cons, prod, size;
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struct xencons_interface *intf = con->sring;
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cons = intf->out_cons;
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prod = intf->out_prod;
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xen_mb();
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size = prod - cons;
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if ((size == 0) || (size > sizeof(intf->out)))
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return;
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if ((buffer->capacity - buffer->size) < size) {
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buffer->capacity += (size + 1024);
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buffer->data = qemu_realloc(buffer->data, buffer->capacity);
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}
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while (cons != prod)
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buffer->data[buffer->size++] = intf->out[
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MASK_XENCONS_IDX(cons++, intf->out)];
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xen_mb();
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intf->out_cons = cons;
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xen_be_send_notify(&con->xendev);
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if (buffer->max_capacity &&
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buffer->size > buffer->max_capacity) {
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/* Discard the middle of the data. */
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size_t over = buffer->size - buffer->max_capacity;
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uint8_t *maxpos = buffer->data + buffer->max_capacity;
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memmove(maxpos - over, maxpos, over);
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buffer->data = qemu_realloc(buffer->data, buffer->max_capacity);
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buffer->size = buffer->capacity = buffer->max_capacity;
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if (buffer->consumed > buffer->max_capacity - over)
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buffer->consumed = buffer->max_capacity - over;
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}
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}
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static void buffer_advance(struct buffer *buffer, size_t len)
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{
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buffer->consumed += len;
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if (buffer->consumed == buffer->size) {
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buffer->consumed = 0;
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buffer->size = 0;
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}
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}
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static int ring_free_bytes(struct XenConsole *con)
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{
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struct xencons_interface *intf = con->sring;
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XENCONS_RING_IDX cons, prod, space;
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cons = intf->in_cons;
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prod = intf->in_prod;
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xen_mb();
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space = prod - cons;
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if (space > sizeof(intf->in))
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return 0; /* ring is screwed: ignore it */
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return (sizeof(intf->in) - space);
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}
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static int xencons_can_receive(void *opaque)
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{
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struct XenConsole *con = opaque;
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return ring_free_bytes(con);
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}
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static void xencons_receive(void *opaque, const uint8_t *buf, int len)
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{
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struct XenConsole *con = opaque;
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struct xencons_interface *intf = con->sring;
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XENCONS_RING_IDX prod;
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int i, max;
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max = ring_free_bytes(con);
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/* The can_receive() func limits this, but check again anyway */
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if (max < len)
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len = max;
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prod = intf->in_prod;
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for (i = 0; i < len; i++) {
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intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
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buf[i];
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}
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xen_wmb();
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intf->in_prod = prod;
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xen_be_send_notify(&con->xendev);
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}
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static void xencons_send(struct XenConsole *con)
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{
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ssize_t len, size;
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size = con->buffer.size - con->buffer.consumed;
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if (con->chr)
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len = qemu_chr_write(con->chr, con->buffer.data + con->buffer.consumed,
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size);
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else
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len = size;
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if (len < 1) {
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if (!con->backlog) {
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con->backlog = 1;
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xen_be_printf(&con->xendev, 1, "backlog piling up, nobody listening?\n");
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}
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} else {
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buffer_advance(&con->buffer, len);
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if (con->backlog && len == size) {
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con->backlog = 0;
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xen_be_printf(&con->xendev, 1, "backlog is gone\n");
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}
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}
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}
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/* -------------------------------------------------------------------- */
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static int con_init(struct XenDevice *xendev)
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{
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struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
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char *type, *dom, label[32];
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int ret = 0;
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const char *output;
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/* setup */
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dom = xs_get_domain_path(xenstore, con->xendev.dom);
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snprintf(con->console, sizeof(con->console), "%s/console", dom);
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free(dom);
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type = xenstore_read_str(con->console, "type");
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if (!type || strcmp(type, "ioemu") != 0) {
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xen_be_printf(xendev, 1, "not for me (type=%s)\n", type);
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ret = -1;
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goto out;
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}
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output = xenstore_read_str(con->console, "output");
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/* no Xen override, use qemu output device */
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if (output == NULL) {
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con->chr = serial_hds[con->xendev.dev];
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} else {
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snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
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con->chr = qemu_chr_open(label, output, NULL);
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}
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xenstore_store_pv_console_info(con->xendev.dev, con->chr);
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out:
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qemu_free(type);
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return ret;
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}
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static int con_connect(struct XenDevice *xendev)
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{
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struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
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int limit;
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if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1)
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return -1;
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if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1)
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return -1;
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if (xenstore_read_int(con->console, "limit", &limit) == 0)
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con->buffer.max_capacity = limit;
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con->sring = xc_map_foreign_range(xen_xc, con->xendev.dom,
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XC_PAGE_SIZE,
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PROT_READ|PROT_WRITE,
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con->ring_ref);
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if (!con->sring)
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return -1;
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xen_be_bind_evtchn(&con->xendev);
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if (con->chr)
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qemu_chr_add_handlers(con->chr, xencons_can_receive, xencons_receive,
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NULL, con);
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xen_be_printf(xendev, 1, "ring mfn %d, remote port %d, local port %d, limit %zd\n",
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con->ring_ref,
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con->xendev.remote_port,
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con->xendev.local_port,
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con->buffer.max_capacity);
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return 0;
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}
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static void con_disconnect(struct XenDevice *xendev)
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{
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struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
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if (con->chr)
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qemu_chr_add_handlers(con->chr, NULL, NULL, NULL, NULL);
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xen_be_unbind_evtchn(&con->xendev);
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if (con->sring) {
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munmap(con->sring, XC_PAGE_SIZE);
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con->sring = NULL;
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}
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}
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static void con_event(struct XenDevice *xendev)
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{
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struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
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buffer_append(con);
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if (con->buffer.size - con->buffer.consumed)
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xencons_send(con);
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}
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/* -------------------------------------------------------------------- */
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struct XenDevOps xen_console_ops = {
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.size = sizeof(struct XenConsole),
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.flags = DEVOPS_FLAG_IGNORE_STATE,
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.init = con_init,
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.connect = con_connect,
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.event = con_event,
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.disconnect = con_disconnect,
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};
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