[v9,3/3] virtio-console: Add a new virtserialport device for generic serial port support

This patch adds generic serial ports over the virtio serial bus.
These ports have a few more options that are not relevant for
virtio console ports: the ability to cache buffers that are
received for a port while it's disconnected, setting of limits
to the bytes that are cached so as to prevent OOM conditions,
etc.

Sample uses for such a device can be obtaining info from the
guest like the file systems used, apps installed, etc. for
offline usage and logged-in users, clipboard copy-paste, etc.
for online usage.

For requirements, use-cases, test cases and some history see

    http://www.linux-kvm.org/page/VMchannel_Requirements

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-console.c |   38 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 38 insertions(+), 0 deletions(-)

> @@ -107,3 +107,41 @@ static void virtcon_register(void)
>       virtio_serial_port_qdev_register(&virtcon_info);
>   }
>   device_init(virtcon_register)

> +static VirtIOSerialPortInfo virtserial_port_info = {
> +    .qdev.name     = "virtserialport",
> +    .qdev.size     = sizeof(VirtConsole),
> +    .init          = virtserial_port_initfn,
> +    .have_data     = flush_buf,
> +    .qdev.props = (Property[]) {
> +        DEFINE_PROP_CHR("chardev", VirtConsole, chr),
> +        DEFINE_PROP_STRING("name", VirtIOSerialPort, name),

likewise: DEFINE_PROP_STRING("name", VirtConsole, port.name),

> +static void virtserial_port_register(void)
> +{
> +    virtio_serial_port_qdev_register(&virtserial_port_info);
> +}
> +device_init(virtserial_port_register)

You can simply stick two register calls into the existing init function ...

cheers,
   Gerd

On (Tue) Oct 20 2009 [10:51:30], Gerd Hoffmann wrote:
>> @@ -107,3 +107,41 @@ static void virtcon_register(void)
>>       virtio_serial_port_qdev_register(&virtcon_info);
>>   }
>>   device_init(virtcon_register)
>
>> +static VirtIOSerialPortInfo virtserial_port_info = {
>> +    .qdev.name     = "virtserialport",
>> +    .qdev.size     = sizeof(VirtConsole),
>> +    .init          = virtserial_port_initfn,
>> +    .have_data     = flush_buf,
>> +    .qdev.props = (Property[]) {
>> +        DEFINE_PROP_CHR("chardev", VirtConsole, chr),
>> +        DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
>
> likewise: DEFINE_PROP_STRING("name", VirtConsole, port.name),

The 'name' field is common to all ports, so it makes sense to put it in
the VirtIOSerialPort struct. (Internal users can pre-define it to their
liking, eg, org.qemu.vnc)

>> +static void virtserial_port_register(void)
>> +{
>> +    virtio_serial_port_qdev_register(&virtserial_port_info);
>> +}
>> +device_init(virtserial_port_register)
>
> You can simply stick two register calls into the existing init function ...

The console init function has extra init'ing to do, like disable buffer
caching, set is_console to true, etc., so there are two init fns.

		Amit

On 10/20/09 11:48, Amit Shah wrote:
> On (Tue) Oct 20 2009 [10:51:30], Gerd Hoffmann wrote:
>>> @@ -107,3 +107,41 @@ static void virtcon_register(void)
>>>        virtio_serial_port_qdev_register(&virtcon_info);
>>>    }
>>>    device_init(virtcon_register)
>>
>>> +static VirtIOSerialPortInfo virtserial_port_info = {
>>> +    .qdev.name     = "virtserialport",
>>> +    .qdev.size     = sizeof(VirtConsole),
>>> +    .init          = virtserial_port_initfn,
>>> +    .have_data     = flush_buf,
>>> +    .qdev.props = (Property[]) {
>>> +        DEFINE_PROP_CHR("chardev", VirtConsole, chr),
>>> +        DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
>>
>> likewise: DEFINE_PROP_STRING("name", VirtConsole, port.name),
>
> The 'name' field is common to all ports, so it makes sense to put it in
> the VirtIOSerialPort struct. (Internal users can pre-define it to their
> liking, eg, org.qemu.vnc)

Sure.  I don't want to move it out there.  But the driver state struct 
is 'VirtConsole' so all properties should use that.  Note that the field 
changed too: from "name" to "port.name", so everything keeps working ;)

cheers,
   Gerd

On (Tue) Oct 20 2009 [16:02:16], Gerd Hoffmann wrote:
> On 10/20/09 11:48, Amit Shah wrote:
>> On (Tue) Oct 20 2009 [10:51:30], Gerd Hoffmann wrote:
>>>> @@ -107,3 +107,41 @@ static void virtcon_register(void)
>>>>        virtio_serial_port_qdev_register(&virtcon_info);
>>>>    }
>>>>    device_init(virtcon_register)
>>>
>>>> +static VirtIOSerialPortInfo virtserial_port_info = {
>>>> +    .qdev.name     = "virtserialport",
>>>> +    .qdev.size     = sizeof(VirtConsole),
>>>> +    .init          = virtserial_port_initfn,
>>>> +    .have_data     = flush_buf,
>>>> +    .qdev.props = (Property[]) {
>>>> +        DEFINE_PROP_CHR("chardev", VirtConsole, chr),
>>>> +        DEFINE_PROP_STRING("name", VirtIOSerialPort, name),
>>>
>>> likewise: DEFINE_PROP_STRING("name", VirtConsole, port.name),
>>
>> The 'name' field is common to all ports, so it makes sense to put it in
>> the VirtIOSerialPort struct. (Internal users can pre-define it to their
>> liking, eg, org.qemu.vnc)
>
> Sure.  I don't want to move it out there.  But the driver state struct  
> is 'VirtConsole' so all properties should use that.  Note that the field  
> changed too: from "name" to "port.name", so everything keeps working ;)

Ah; I understand it now. Sorry for the confusion.

Thanks Gerd for the reviews.

		Amit