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xen-devel
[Xen-devel] Re: [Qemu-devel] [PATCH 3/7] xen: add console backend driver
Gerd Hoffmann wrote:
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: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
Makefile.target | 1 +
hw/xen-backend.h | 3 +
hw/xen-console.c | 271 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
hw/xen-machine.c | 2 +
4 files changed, 277 insertions(+), 0 deletions(-)
create mode 100644 hw/xen-console.c
diff --git a/Makefile.target b/Makefile.target
index 0451048..05619fa 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -517,6 +517,7 @@ endif
# xen backend driver support
XEN_OBJS := xen-machine.o xen-backend.o
+XEN_OBJS += xen-console.o
ifeq ($(CONFIG_XEN), yes)
OBJS += $(XEN_OBJS)
LIBS += $(XEN_LIBS)
diff --git a/hw/xen-backend.h b/hw/xen-backend.h
index db36ae7..55ffd31 100644
--- a/hw/xen-backend.h
+++ b/hw/xen-backend.h
@@ -114,3 +114,6 @@ int xen_be_send_notify(struct xendev *xendev);
void xen_be_printf(struct xendev *xendev, int msg_level, const char *fmt, ...)
__attribute__ ((format(printf, 3, 4)));
+/* actual backend drivers */
+struct devops xen_console_ops; /* xen_console.c */
+
diff --git a/hw/xen-console.c b/hw/xen-console.c
new file mode 100644
index 0000000..9c67f1b
--- /dev/null
+++ b/hw/xen-console.c
@@ -0,0 +1,271 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2005
+ * Author(s): Anthony Liguori <aliguori@xxxxxxxxxx>
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <malloc.h>
+#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"
+
+#define dolog(val, fmt, ...) fprintf(stderr, fmt "\n", ## __VA_ARGS__)
+
+struct buffer {
+ uint8_t *data;
+ size_t consumed;
+ size_t size;
+ size_t capacity;
+ size_t max_capacity;
+};
+
+struct xen_console {
+ struct xendev xendev; /* must be first */
+ struct buffer buffer;
+ char console[BUFSIZE];
+ int ring_ref;
+ void *sring;
+ CharDriverState *chr;
+ int backlog;
+};
+
+static void buffer_append(struct xen_console *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 = realloc(buffer->data, buffer->capacity);
+ if (buffer->data == NULL) {
+ dolog(LOG_ERR, "Memory allocation failed");
+ exit(ENOMEM);
+ }
+ }
+
+ 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 = 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 xen_console *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 xen_console *con = opaque;
+ return ring_free_bytes(con);
+}
+
+static void xencons_receive(void *opaque, const uint8_t *buf, int len)
+{
+ struct xen_console *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 xen_console *con)
+{
+ ssize_t len, size;
+
+ size = con->buffer.size - con->buffer.consumed;
+ len = qemu_chr_write(con->chr, con->buffer.data + con->buffer.consumed,
+ 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 xendev *xendev)
+{
+ struct xen_console *con = container_of(xendev, struct xen_console, xendev);
+ char *type;
+
+ if (!serial_hds[con->xendev.dev]) {
+ xen_be_printf(xendev, 1, "serial line %d not configured\n",
con->xendev.dev);
+ return -1;
+ }
+
+ /* setup */
+ snprintf(con->console, sizeof(con->console),
+ "/local/domain/%d/console", con->xendev.dom);
+ con->chr = serial_hds[con->xendev.dev];
+
+ 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;
+ }
+
+ return 0;
+}
+
+static int con_connect(struct xendev *xendev)
+{
+ struct xen_console *con = container_of(xendev, struct xen_console, xendev);
+ int limit;
+
+ if (-1 == xenstore_read_int(con->console, "ring-ref", &con->ring_ref))
+ return -1;
+ if (-1 == xenstore_read_int(con->console, "port",
&con->xendev.remote_port))
+ return -1;
+ if (0 == xenstore_read_int(con->console, "limit", &limit))
+ 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);
+ 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 xendev *xendev)
+{
+ struct xen_console *con = container_of(xendev, struct xen_console, xendev);
+
+ 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 xendev *xendev)
+{
+ struct xen_console *con = container_of(xendev, struct xen_console, xendev);
+
+ buffer_append(con);
+ if (con->buffer.size - con->buffer.consumed)
+ xencons_send(con);
+}
+
+/* -------------------------------------------------------------------- */
+
+struct devops xen_console_ops = {
I missed it in the previous patchset, but it would be nice to QEMU-ify
these things. For instance, 'struct xen_console' => 'XenConsole',
'struct devopts' => 'XenDevOpts', etc.
Regards,
Anthony Liguori
+ .size = sizeof(struct xen_console),
+ .flags = DEVOPS_FLAG_IGNORE_STATE,
+ .init = con_init,
+ .connect = con_connect,
+ .event = con_event,
+ .disconnect = con_disconnect,
+};
diff --git a/hw/xen-machine.c b/hw/xen-machine.c
index 798c0a7..da10982 100644
--- a/hw/xen-machine.c
+++ b/hw/xen-machine.c
@@ -57,6 +57,8 @@ static void xenpv_init(ram_addr_t ram_size, int vga_ram_size,
/* setup xen backend handlers */
xen_be_init();
+
+ xen_be_register("console", &xen_console_ops);
}
QEMUMachine xenpv_machine = {
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