hw/char/xen_console.c - qemu - Git at Google

 /*
  *  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 <stdlib.h>
 #include <errno.h>
 #include <string.h>
 #include <sys/select.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <termios.h>
 #include <stdarg.h>
 #include <sys/mman.h>

 #include "hw/hw.h"
 #include "sysemu/char.h"
 #include "hw/xen/xen_backend.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;
     CharDriverState   *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_be_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_be_send_notify(&con->xendev);
 }

 static void xencons_send(struct XenConsole *con)
 {
     ssize_t len, size;

     size = con->buffer.size - con->buffer.consumed;
     if (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_be_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_be_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_be_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) {
         con->chr = serial_hds[con->xendev.dev];
     } else {
         snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
         con->chr = qemu_chr_new(label, output, NULL);
     }

     xenstore_store_pv_console_info(con->xendev.dev, 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) {
         con->sring = xc_map_foreign_range(xen_xc, con->xendev.dom,
                                           XC_PAGE_SIZE,
                                           PROT_READ|PROT_WRITE,
                                           con->ring_ref);
     } else {
         con->sring = xc_gnttab_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);
     if (con->chr) {
         if (qemu_chr_fe_claim(con->chr) == 0) {
             qemu_chr_add_handlers(con->chr, xencons_can_receive,
                                   xencons_receive, NULL, con);
         } else {
             xen_be_printf(xendev, 0,
                           "xen_console_init error chardev %s already used\n",
                           con->chr->label);
             con->chr = NULL;
         }
     }

     xen_be_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);

     if (!xendev->dev) {
         return;
     }
     if (con->chr) {
         qemu_chr_add_handlers(con->chr, NULL, NULL, NULL, NULL);
         qemu_chr_fe_release(con->chr);
     }
     xen_be_unbind_evtchn(&con->xendev);

     if (con->sring) {
         if (!xendev->gnttabdev) {
             munmap(con->sring, XC_PAGE_SIZE);
         } else {
             xc_gnttab_munmap(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,
 };
	/*
	* 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 <stdlib.h>
	#include <errno.h>
	#include <string.h>
	#include <sys/select.h>
	#include <fcntl.h>
	#include <unistd.h>
	#include <termios.h>
	#include <stdarg.h>
	#include <sys/mman.h>

	#include "hw/hw.h"
	#include "sysemu/char.h"
	#include "hw/xen/xen_backend.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;
	CharDriverState *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_be_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_be_send_notify(&con->xendev);
	}

	static void xencons_send(struct XenConsole *con)
	{
	ssize_t len, size;

	size = con->buffer.size - con->buffer.consumed;
	if (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_be_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_be_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_be_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) {
	con->chr = serial_hds[con->xendev.dev];
	} else {
	snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
	con->chr = qemu_chr_new(label, output, NULL);
	}

	xenstore_store_pv_console_info(con->xendev.dev, 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) {
	con->sring = xc_map_foreign_range(xen_xc, con->xendev.dom,
	XC_PAGE_SIZE,
	PROT_READ\|PROT_WRITE,
	con->ring_ref);
	} else {
	con->sring = xc_gnttab_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);
	if (con->chr) {
	if (qemu_chr_fe_claim(con->chr) == 0) {
	qemu_chr_add_handlers(con->chr, xencons_can_receive,
	xencons_receive, NULL, con);
	} else {
	xen_be_printf(xendev, 0,
	"xen_console_init error chardev %s already used\n",
	con->chr->label);
	con->chr = NULL;
	}
	}

	xen_be_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);

	if (!xendev->dev) {
	return;
	}
	if (con->chr) {
	qemu_chr_add_handlers(con->chr, NULL, NULL, NULL, NULL);
	qemu_chr_fe_release(con->chr);
	}
	xen_be_unbind_evtchn(&con->xendev);

	if (con->sring) {
	if (!xendev->gnttabdev) {
	munmap(con->sring, XC_PAGE_SIZE);
	} else {
	xc_gnttab_munmap(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,
	};