Commit e57dd20b authored by Anthony Liguori's avatar Anthony Liguori
Browse files

xen: add console backend driver. (Gerd Hoffmann) 



This patch adds a xenconsole backend driver.  It it based on current
xen-unstable code.  It has been changed to make use of the common
backend driver code.

Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7221 c046a42c-6fe2-441c-8c8c-71466251a162
parent d94f9486

Makefile.target

+1 −0
Original line number Diff line number Diff line
@@ -562,6 +562,7 @@ endif 


# xen backend driver support

XEN_OBJS := xen_machine_pv.o xen_backend.o

XEN_OBJS += xen_console.o

ifeq ($(CONFIG_XEN), yes)

  OBJS += $(XEN_OBJS)

  LIBS += $(XEN_LIBS)

hw/xen_backend.h

+3 −0
Original line number Diff line number Diff line
@@ -83,4 +83,7 @@ int xen_be_send_notify(struct XenDevice *xendev); 
void xen_be_printf(struct XenDevice *xendev, int msg_level, const char *fmt, ...)

    __attribute__ ((format(printf, 3, 4)));



/* actual backend drivers */

extern struct XenDevOps xen_console_ops;      /* xen_console.c     */



#endif /* QEMU_HW_XEN_BACKEND_H */

hw/xen_console.c

0 → 100644
+270 −0
Original line number Diff line number Diff line 
/*

 *  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, write to the Free Software Foundation, Inc.,

 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */



#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 <xs.h>

#include <xen/io/console.h>

#include <xenctrl.h>



#include "hw.h"

#include "sysemu.h"

#include "qemu-char.h"

#include "xen_backend.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 = qemu_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 = qemu_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_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;



    /* setup */

    dom = xs_get_domain_path(xenstore, con->xendev.dom);

    snprintf(con->console, sizeof(con->console), "%s/console", dom);

    free(dom);



    type = xenstore_read_str(con->console, "type");

    if (!type || 0 != strcmp(type, "ioemu")) {

	xen_be_printf(xendev, 1, "not for me (type=%s)\n", type);

	return -1;

    }



    if (!serial_hds[con->xendev.dev])

	xen_be_printf(xendev, 1, "WARNING: serial line %d not configured\n",

                      con->xendev.dev);

    else

        con->chr = serial_hds[con->xendev.dev];



    return 0;

}



static int con_connect(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;



    con->sring = xc_map_foreign_range(xen_xc, con->xendev.dom,

				      XC_PAGE_SIZE,

				      PROT_READ|PROT_WRITE,

				      con->ring_ref);

    if (!con->sring)

	return -1;



    xen_be_bind_evtchn(&con->xendev);

    if (con->chr)

        qemu_chr_add_handlers(con->chr, xencons_can_receive, xencons_receive,

                              NULL, con);



    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 (con->chr)

        qemu_chr_add_handlers(con->chr, NULL, NULL, NULL, NULL);

    xen_be_unbind_evtchn(&con->xendev);



    if (con->sring) {

	munmap(con->sring, XC_PAGE_SIZE);

	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,

    .init       = con_init,

    .connect    = con_connect,

    .event      = con_event,

    .disconnect = con_disconnect,

};

hw/xen_machine_pv.c

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ static void xen_init_pv(ram_addr_t ram_size, int vga_ram_size, 
        fprintf(stderr, "%s: xen backend core setup failed\n", __FUNCTION__);

        exit(1);

    }

    xen_be_register("console", &xen_console_ops);

}



QEMUMachine xenpv_machine = {