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virtio-serial: Use control messages to notify guest of new ports 

Allow the port 'id's to be set by a user on the command line. This is
needed by management apps that will want a stable port numbering scheme
for hot-plug/unplug and migration.

Since the port numbers are shared with the guest (to identify ports in
control messages), we just send a control message to the guest
indicating addition of new ports (hot-plug) or notifying the guest of
the available ports when the guest sends us a DEVICE_READY control
message.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Amit Shah 2010-04-27 18:03:59 +05:30 committed by Anthony Liguori
parent 31abe21f4f
commit 055b889f94
3 changed files with 135 additions and 72 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
hw/virtio-console.c
View File

@ -99,6 +99,7 @@ static VirtIOSerialPortInfo virtconsole_info = {
.exit = virtconsole_exitfn,
.qdev.props = (Property[]) {
DEFINE_PROP_UINT8("is_console", VirtConsole, port.is_console, 1),
DEFINE_PROP_UINT32("nr", VirtConsole, port.id, VIRTIO_CONSOLE_BAD_ID),
DEFINE_PROP_CHR("chardev", VirtConsole, chr),
DEFINE_PROP_STRING("name", VirtConsole, port.name),
DEFINE_PROP_END_OF_LIST(),
@ -133,6 +134,7 @@ static VirtIOSerialPortInfo virtserialport_info = {
.init = virtserialport_initfn,
.exit = virtconsole_exitfn,
.qdev.props = (Property[]) {
DEFINE_PROP_UINT32("nr", VirtConsole, port.id, VIRTIO_CONSOLE_BAD_ID),
DEFINE_PROP_CHR("chardev", VirtConsole, chr),
DEFINE_PROP_STRING("name", VirtConsole, port.name),
DEFINE_PROP_END_OF_LIST(),

188
hw/virtio-serial-bus.c
View File

@ -41,6 +41,10 @@ struct VirtIOSerial {
VirtIOSerialBus *bus;
QTAILQ_HEAD(, VirtIOSerialPort) ports;
/* bitmap for identifying active ports */
uint32_t *ports_map;
struct virtio_console_config config;
};
@ -48,6 +52,10 @@ static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
{
VirtIOSerialPort *port;
if (id == VIRTIO_CONSOLE_BAD_ID) {
return NULL;
}
QTAILQ_FOREACH(port, &vser->ports, next) {
if (port->id == id)
return port;
@ -208,14 +216,25 @@ static void handle_control_message(VirtIOSerial *vser, void *buf)
size_t buffer_len;
gcpkt = buf;
port = find_port_by_id(vser, ldl_p(&gcpkt->id));
if (!port)
return;
cpkt.event = lduw_p(&gcpkt->event);
cpkt.value = lduw_p(&gcpkt->value);
port = find_port_by_id(vser, ldl_p(&gcpkt->id));
if (!port && cpkt.event != VIRTIO_CONSOLE_DEVICE_READY)
return;
switch(cpkt.event) {
case VIRTIO_CONSOLE_DEVICE_READY:
/*
* The device is up, we can now tell the device about all the
* ports we have here.
*/
QTAILQ_FOREACH(port, &vser->ports, next) {
send_control_event(port, VIRTIO_CONSOLE_PORT_ADD, 1);
}
break;
case VIRTIO_CONSOLE_PORT_READY:
/*
* Now that we know the guest asked for the port name, we're
@ -363,6 +382,7 @@ static void virtio_serial_save(QEMUFile *f, void *opaque)
VirtIOSerial *s = opaque;
VirtIOSerialPort *port;
uint32_t nr_active_ports;
unsigned int i;
/* The virtio device */
virtio_save(&s->vdev, f);
@ -370,13 +390,17 @@ static void virtio_serial_save(QEMUFile *f, void *opaque)
/* The config space */
qemu_put_be16s(f, &s->config.cols);
qemu_put_be16s(f, &s->config.rows);
qemu_put_be32s(f, &s->config.nr_ports);
/* Items in struct VirtIOSerial */
qemu_put_be32s(f, &s->config.max_nr_ports);
qemu_put_be32s(f, &s->bus->max_nr_ports);
/* The ports map */
for (i = 0; i < (s->config.max_nr_ports + 31) / 32; i++) {
qemu_put_be32s(f, &s->ports_map[i]);
}
/* Ports */
/* Do this because we might have hot-unplugged some ports */
nr_active_ports = 0;
QTAILQ_FOREACH(port, &s->ports, next) {
nr_active_ports++;
@ -388,11 +412,6 @@ static void virtio_serial_save(QEMUFile *f, void *opaque)
* Items in struct VirtIOSerialPort.
*/
QTAILQ_FOREACH(port, &s->ports, next) {
/*
* We put the port number because we may not have an active
* port at id 0 that's reserved for a console port, or in case
* of ports that might have gotten unplugged
*/
qemu_put_be32s(f, &port->id);
qemu_put_byte(f, port->guest_connected);
qemu_put_byte(f, port->host_connected);
@ -403,7 +422,8 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
{
VirtIOSerial *s = opaque;
VirtIOSerialPort *port;
uint32_t max_nr_ports, nr_active_ports, nr_ports;
size_t ports_map_size;
uint32_t max_nr_ports, nr_active_ports, *ports_map;
unsigned int i;
if (version_id > 2) {
@ -420,30 +440,30 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
/* The config space */
qemu_get_be16s(f, &s->config.cols);
qemu_get_be16s(f, &s->config.rows);
nr_ports = qemu_get_be32(f);
if (nr_ports != s->config.nr_ports) {
/*
* Source hot-plugged/unplugged ports and we don't have all of
* them here.
*
* Note: This condition cannot check for all hotplug/unplug
* events: eg, if one port was hot-plugged and one was
* unplugged, the nr_ports remains the same but the port id's
* would have changed and we won't catch it here. A later
* check for !find_port_by_id() will confirm if this happened.
*/
return -EINVAL;
}
/* Items in struct VirtIOSerial */
qemu_get_be32s(f, &max_nr_ports);
if (max_nr_ports > s->bus->max_nr_ports) {
/* Source could have more ports than us. Fail migration. */
if (max_nr_ports > s->config.max_nr_ports) {
/* Source could have had more ports than us. Fail migration. */
return -EINVAL;
}
ports_map_size = sizeof(uint32_t) * (max_nr_ports + 31) / 32;
ports_map = qemu_malloc(ports_map_size);
for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
qemu_get_be32s(f, &ports_map[i]);
if (ports_map[i] != s->ports_map[i]) {
/*
* Ports active on source and destination don't
* match. Fail migration.
*/
qemu_free(ports_map);
return -EINVAL;
}
}
qemu_free(ports_map);
qemu_get_be32s(f, &nr_active_ports);
/* Items in struct VirtIOSerialPort */
@ -453,13 +473,6 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
id = qemu_get_be32(f);
port = find_port_by_id(s, id);
if (!port) {
/*
* The requested port was hot-plugged on the source but we
* don't have it
*/
return -EINVAL;
}
port->guest_connected = qemu_get_byte(f);
host_connected = qemu_get_byte(f);
@ -472,7 +485,6 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
port->host_connected);
}
}
return 0;
}
@ -507,6 +519,50 @@ static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
indent, "", port->host_connected);
}
/* This function is only used if a port id is not provided by the user */
static uint32_t find_free_port_id(VirtIOSerial *vser)
{
unsigned int i;
for (i = 0; i < (vser->config.max_nr_ports + 31) / 32; i++) {
uint32_t map, bit;
map = vser->ports_map[i];
bit = ffs(~map);
if (bit) {
return (bit - 1) + i * 32;
}
}
return VIRTIO_CONSOLE_BAD_ID;
}
static void mark_port_added(VirtIOSerial *vser, uint32_t port_id)
{
unsigned int i;
i = port_id / 32;
vser->ports_map[i] |= 1U << (port_id % 32);
}
static void add_port(VirtIOSerial *vser, uint32_t port_id)
{
mark_port_added(vser, port_id);
send_control_event(find_port_by_id(vser, port_id),
VIRTIO_CONSOLE_PORT_ADD, 1);
}
static void remove_port(VirtIOSerial *vser, uint32_t port_id)
{
unsigned int i;
i = port_id / 32;
vser->ports_map[i] &= ~(1U << (port_id % 32));
send_control_event(find_port_by_id(vser, port_id),
VIRTIO_CONSOLE_PORT_REMOVE, 1);
}
static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
{
VirtIOSerialDevice *dev = DO_UPCAST(VirtIOSerialDevice, qdev, qdev);
@ -525,19 +581,36 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
*/
plugging_port0 = port->is_console && !find_port_by_id(port->vser, 0);
if (port->vser->config.nr_ports == bus->max_nr_ports && !plugging_port0) {
error_report("virtio-serial-bus: Maximum device limit reached");
if (find_port_by_id(port->vser, port->id)) {
error_report("virtio-serial-bus: A port already exists at id %u\n",
port->id);
return -1;
}
dev->info = info;
if (port->id == VIRTIO_CONSOLE_BAD_ID) {
if (plugging_port0) {
port->id = 0;
} else {
port->id = find_free_port_id(port->vser);
if (port->id == VIRTIO_CONSOLE_BAD_ID) {
error_report("virtio-serial-bus: Maximum port limit for this device reached\n");
return -1;
}
}
}
if (port->id >= port->vser->config.max_nr_ports) {
error_report("virtio-serial-bus: Out-of-range port id specified, max. allowed: %u\n",
port->vser->config.max_nr_ports - 1);
return -1;
}
dev->info = info;
ret = info->init(dev);
if (ret) {
return ret;
}
port->id = plugging_port0 ? 0 : port->vser->config.nr_ports++;
if (!use_multiport(port->vser)) {
/*
* Allow writes to guest in this case; we have no way of
@ -550,6 +623,8 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
port->ivq = port->vser->ivqs[port->id];
port->ovq = port->vser->ovqs[port->id];
add_port(port->vser, port->id);
/* Send an update to the guest about this new port added */
virtio_notify_config(&port->vser->vdev);
@ -562,26 +637,8 @@ static int virtser_port_qdev_exit(DeviceState *qdev)
VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);
VirtIOSerial *vser = port->vser;
send_control_event(port, VIRTIO_CONSOLE_PORT_REMOVE, 1);
remove_port(port->vser, port->id);
/*
* Don't decrement nr_ports here; thus we keep a linearly
* increasing port id. Not utilising an id again saves us a couple
* of complications:
*
* - Not having to bother about sending the port id to the guest
* kernel on hotplug or on addition of new ports; the guest can
* also linearly increment the port number. This is preferable
* because the config space won't have the need to store a
* ports_map.
*
* - Extra state to be stored for all the "holes" that got created
* so that we keep filling in the ids from the least available
* index.
*
* When such a functionality is desired, a control message to add
* a port can be introduced.
*/
QTAILQ_REMOVE(&vser->ports, port, next);
if (port->info->exit)
@ -641,11 +698,12 @@ VirtIODevice *virtio_serial_init(DeviceState *dev, uint32_t max_nr_ports)
}
vser->config.max_nr_ports = max_nr_ports;
vser->ports_map = qemu_mallocz((max_nr_ports + 31) / 32);
/*
* Reserve location 0 for a console port for backward compat
* (old kernel, new qemu)
*/
vser->config.nr_ports = 1;
mark_port_added(vser, 0);
vser->vdev.get_features = get_features;
vser->vdev.get_config = get_config;

17
hw/virtio-serial.h
View File

@ -27,6 +27,8 @@
/* Features supported */
#define VIRTIO_CONSOLE_F_MULTIPORT 1
#define VIRTIO_CONSOLE_BAD_ID (~(uint32_t)0)
struct virtio_console_config {
/*
* These two fields are used by VIRTIO_CONSOLE_F_SIZE which
@ -36,7 +38,6 @@ struct virtio_console_config {
uint16_t rows;
uint32_t max_nr_ports;
uint32_t nr_ports;
} __attribute__((packed));
struct virtio_console_control {
@ -46,12 +47,14 @@ struct virtio_console_control {
};
/* Some events for the internal messages (control packets) */
#define VIRTIO_CONSOLE_PORT_READY 0
#define VIRTIO_CONSOLE_CONSOLE_PORT 1
#define VIRTIO_CONSOLE_RESIZE 2
#define VIRTIO_CONSOLE_PORT_OPEN 3
#define VIRTIO_CONSOLE_PORT_NAME 4
#define VIRTIO_CONSOLE_PORT_REMOVE 5
#define VIRTIO_CONSOLE_DEVICE_READY 0
#define VIRTIO_CONSOLE_PORT_ADD 1
#define VIRTIO_CONSOLE_PORT_REMOVE 2
#define VIRTIO_CONSOLE_PORT_READY 3
#define VIRTIO_CONSOLE_CONSOLE_PORT 4
#define VIRTIO_CONSOLE_RESIZE 5
#define VIRTIO_CONSOLE_PORT_OPEN 6
#define VIRTIO_CONSOLE_PORT_NAME 7
/* == In-qemu interface == */