root / hw / xen_console.c @ 25a11813
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/*
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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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}; |