Annotation of qemu/hw/xen_console.c, revision 1.1

1.1     ! root        1: /*
        !             2:  *  Copyright (C) International Business Machines  Corp., 2005
        !             3:  *  Author(s): Anthony Liguori <aliguori@us.ibm.com>
        !             4:  *
        !             5:  *  Copyright (C) Red Hat 2007
        !             6:  *
        !             7:  *  Xen Console
        !             8:  *
        !             9:  *  This program is free software; you can redistribute it and/or modify
        !            10:  *  it under the terms of the GNU General Public License as published by
        !            11:  *  the Free Software Foundation; under version 2 of the License.
        !            12:  *
        !            13:  *  This program is distributed in the hope that it will be useful,
        !            14:  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            15:  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            16:  *  GNU General Public License for more details.
        !            17:  *
        !            18:  *  You should have received a copy of the GNU General Public License along
        !            19:  *  with this program; if not, see <http://www.gnu.org/licenses/>.
        !            20:  */
        !            21: 
        !            22: #include <stdlib.h>
        !            23: #include <errno.h>
        !            24: #include <string.h>
        !            25: #include <sys/select.h>
        !            26: #include <fcntl.h>
        !            27: #include <unistd.h>
        !            28: #include <termios.h>
        !            29: #include <stdarg.h>
        !            30: #include <sys/mman.h>
        !            31: #include <xs.h>
        !            32: #include <xen/io/console.h>
        !            33: #include <xenctrl.h>
        !            34: 
        !            35: #include "hw.h"
        !            36: #include "sysemu.h"
        !            37: #include "qemu-char.h"
        !            38: #include "xen_backend.h"
        !            39: 
        !            40: struct buffer {
        !            41:     uint8_t *data;
        !            42:     size_t consumed;
        !            43:     size_t size;
        !            44:     size_t capacity;
        !            45:     size_t max_capacity;
        !            46: };
        !            47: 
        !            48: struct XenConsole {
        !            49:     struct XenDevice  xendev;  /* must be first */
        !            50:     struct buffer     buffer;
        !            51:     char              console[XEN_BUFSIZE];
        !            52:     int               ring_ref;
        !            53:     void              *sring;
        !            54:     CharDriverState   *chr;
        !            55:     int               backlog;
        !            56: };
        !            57: 
        !            58: static void buffer_append(struct XenConsole *con)
        !            59: {
        !            60:     struct buffer *buffer = &con->buffer;
        !            61:     XENCONS_RING_IDX cons, prod, size;
        !            62:     struct xencons_interface *intf = con->sring;
        !            63: 
        !            64:     cons = intf->out_cons;
        !            65:     prod = intf->out_prod;
        !            66:     xen_mb();
        !            67: 
        !            68:     size = prod - cons;
        !            69:     if ((size == 0) || (size > sizeof(intf->out)))
        !            70:        return;
        !            71: 
        !            72:     if ((buffer->capacity - buffer->size) < size) {
        !            73:        buffer->capacity += (size + 1024);
        !            74:        buffer->data = qemu_realloc(buffer->data, buffer->capacity);
        !            75:     }
        !            76: 
        !            77:     while (cons != prod)
        !            78:        buffer->data[buffer->size++] = intf->out[
        !            79:            MASK_XENCONS_IDX(cons++, intf->out)];
        !            80: 
        !            81:     xen_mb();
        !            82:     intf->out_cons = cons;
        !            83:     xen_be_send_notify(&con->xendev);
        !            84: 
        !            85:     if (buffer->max_capacity &&
        !            86:        buffer->size > buffer->max_capacity) {
        !            87:        /* Discard the middle of the data. */
        !            88: 
        !            89:        size_t over = buffer->size - buffer->max_capacity;
        !            90:        uint8_t *maxpos = buffer->data + buffer->max_capacity;
        !            91: 
        !            92:        memmove(maxpos - over, maxpos, over);
        !            93:        buffer->data = qemu_realloc(buffer->data, buffer->max_capacity);
        !            94:        buffer->size = buffer->capacity = buffer->max_capacity;
        !            95: 
        !            96:        if (buffer->consumed > buffer->max_capacity - over)
        !            97:            buffer->consumed = buffer->max_capacity - over;
        !            98:     }
        !            99: }
        !           100: 
        !           101: static void buffer_advance(struct buffer *buffer, size_t len)
        !           102: {
        !           103:     buffer->consumed += len;
        !           104:     if (buffer->consumed == buffer->size) {
        !           105:        buffer->consumed = 0;
        !           106:        buffer->size = 0;
        !           107:     }
        !           108: }
        !           109: 
        !           110: static int ring_free_bytes(struct XenConsole *con)
        !           111: {
        !           112:     struct xencons_interface *intf = con->sring;
        !           113:     XENCONS_RING_IDX cons, prod, space;
        !           114: 
        !           115:     cons = intf->in_cons;
        !           116:     prod = intf->in_prod;
        !           117:     xen_mb();
        !           118: 
        !           119:     space = prod - cons;
        !           120:     if (space > sizeof(intf->in))
        !           121:        return 0; /* ring is screwed: ignore it */
        !           122: 
        !           123:     return (sizeof(intf->in) - space);
        !           124: }
        !           125: 
        !           126: static int xencons_can_receive(void *opaque)
        !           127: {
        !           128:     struct XenConsole *con = opaque;
        !           129:     return ring_free_bytes(con);
        !           130: }
        !           131: 
        !           132: static void xencons_receive(void *opaque, const uint8_t *buf, int len)
        !           133: {
        !           134:     struct XenConsole *con = opaque;
        !           135:     struct xencons_interface *intf = con->sring;
        !           136:     XENCONS_RING_IDX prod;
        !           137:     int i, max;
        !           138: 
        !           139:     max = ring_free_bytes(con);
        !           140:     /* The can_receive() func limits this, but check again anyway */
        !           141:     if (max < len)
        !           142:        len = max;
        !           143: 
        !           144:     prod = intf->in_prod;
        !           145:     for (i = 0; i < len; i++) {
        !           146:        intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
        !           147:            buf[i];
        !           148:     }
        !           149:     xen_wmb();
        !           150:     intf->in_prod = prod;
        !           151:     xen_be_send_notify(&con->xendev);
        !           152: }
        !           153: 
        !           154: static void xencons_send(struct XenConsole *con)
        !           155: {
        !           156:     ssize_t len, size;
        !           157: 
        !           158:     size = con->buffer.size - con->buffer.consumed;
        !           159:     if (con->chr)
        !           160:         len = qemu_chr_write(con->chr, con->buffer.data + con->buffer.consumed,
        !           161:                              size);
        !           162:     else
        !           163:         len = size;
        !           164:     if (len < 1) {
        !           165:        if (!con->backlog) {
        !           166:            con->backlog = 1;
        !           167:            xen_be_printf(&con->xendev, 1, "backlog piling up, nobody listening?\n");
        !           168:        }
        !           169:     } else {
        !           170:        buffer_advance(&con->buffer, len);
        !           171:        if (con->backlog && len == size) {
        !           172:            con->backlog = 0;
        !           173:            xen_be_printf(&con->xendev, 1, "backlog is gone\n");
        !           174:        }
        !           175:     }
        !           176: }
        !           177: 
        !           178: /* -------------------------------------------------------------------- */
        !           179: 
        !           180: static int con_init(struct XenDevice *xendev)
        !           181: {
        !           182:     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
        !           183:     char *type, *dom;
        !           184: 
        !           185:     /* setup */
        !           186:     dom = xs_get_domain_path(xenstore, con->xendev.dom);
        !           187:     snprintf(con->console, sizeof(con->console), "%s/console", dom);
        !           188:     free(dom);
        !           189: 
        !           190:     type = xenstore_read_str(con->console, "type");
        !           191:     if (!type || strcmp(type, "ioemu") != 0) {
        !           192:        xen_be_printf(xendev, 1, "not for me (type=%s)\n", type);
        !           193:        return -1;
        !           194:     }
        !           195: 
        !           196:     if (!serial_hds[con->xendev.dev])
        !           197:        xen_be_printf(xendev, 1, "WARNING: serial line %d not configured\n",
        !           198:                       con->xendev.dev);
        !           199:     else
        !           200:         con->chr = serial_hds[con->xendev.dev];
        !           201: 
        !           202:     return 0;
        !           203: }
        !           204: 
        !           205: static int con_connect(struct XenDevice *xendev)
        !           206: {
        !           207:     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
        !           208:     int limit;
        !           209: 
        !           210:     if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1)
        !           211:        return -1;
        !           212:     if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1)
        !           213:        return -1;
        !           214:     if (xenstore_read_int(con->console, "limit", &limit) == 0)
        !           215:        con->buffer.max_capacity = limit;
        !           216: 
        !           217:     con->sring = xc_map_foreign_range(xen_xc, con->xendev.dom,
        !           218:                                      XC_PAGE_SIZE,
        !           219:                                      PROT_READ|PROT_WRITE,
        !           220:                                      con->ring_ref);
        !           221:     if (!con->sring)
        !           222:        return -1;
        !           223: 
        !           224:     xen_be_bind_evtchn(&con->xendev);
        !           225:     if (con->chr)
        !           226:         qemu_chr_add_handlers(con->chr, xencons_can_receive, xencons_receive,
        !           227:                               NULL, con);
        !           228: 
        !           229:     xen_be_printf(xendev, 1, "ring mfn %d, remote port %d, local port %d, limit %zd\n",
        !           230:                  con->ring_ref,
        !           231:                  con->xendev.remote_port,
        !           232:                  con->xendev.local_port,
        !           233:                  con->buffer.max_capacity);
        !           234:     return 0;
        !           235: }
        !           236: 
        !           237: static void con_disconnect(struct XenDevice *xendev)
        !           238: {
        !           239:     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
        !           240: 
        !           241:     if (con->chr)
        !           242:         qemu_chr_add_handlers(con->chr, NULL, NULL, NULL, NULL);
        !           243:     xen_be_unbind_evtchn(&con->xendev);
        !           244: 
        !           245:     if (con->sring) {
        !           246:        munmap(con->sring, XC_PAGE_SIZE);
        !           247:        con->sring = NULL;
        !           248:     }
        !           249: }
        !           250: 
        !           251: static void con_event(struct XenDevice *xendev)
        !           252: {
        !           253:     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
        !           254: 
        !           255:     buffer_append(con);
        !           256:     if (con->buffer.size - con->buffer.consumed)
        !           257:        xencons_send(con);
        !           258: }
        !           259: 
        !           260: /* -------------------------------------------------------------------- */
        !           261: 
        !           262: struct XenDevOps xen_console_ops = {
        !           263:     .size       = sizeof(struct XenConsole),
        !           264:     .flags      = DEVOPS_FLAG_IGNORE_STATE,
        !           265:     .init       = con_init,
        !           266:     .connect    = con_connect,
        !           267:     .event      = con_event,
        !           268:     .disconnect = con_disconnect,
        !           269: };

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