[Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Amit Shah]

Hello,

This series addresses some comments from last time:
- locking is removed
- send/receive struct elements in endian-safe way
- appropriate device is created based on machine being used
  (virtio-serial-pci vs virtio-serial-s390).

This series splits up the patches by functionality. Note, however,
that patches 2-6 introduce some functionality that's advertised to the
guest as having to work all at once or not at all. Also, the savevm
version is bumped only once but save/restore state is added in each of
the patches. They are split only for easier reviewability.

The older virtio-console.c file is completely removed and a new
virtio-serial.c is introduced so that reviewing is easier. I can send a
later patch to rename virtio-serial.c back to virtio-console.c.

Amit Shah (8):
  virtio: Remove duplicate macro definition for max. virtqueues, bump
    up the max
  virtio-console: qdev conversion, new virtio-serial-bus
  virtio-serial-bus: Maintain guest and host port open/close state
  virtio-serial-bus: Add a port 'name' property for port discovery in
    guests
  virtio-serial-bus: Add support for buffering guest output, throttling
    guests
  virtio-serial-bus: Add ability to hot-unplug ports
  virtio-serial: Add 'virtserialport' device for generic serial port
    support
  Move virtio-serial and virtio-serial-bus to Makefile.hw

 Makefile.hw            |    2 +-
 Makefile.target        |    2 +-
 hw/pc.c                |   11 +-
 hw/ppc440_bamboo.c     |    7 -
 hw/qdev.c              |    8 +-
 hw/s390-virtio-bus.c   |   17 +-
 hw/s390-virtio-bus.h   |    2 +
 hw/s390-virtio.c       |    8 -
 hw/virtio-console.c    |  143 --------
 hw/virtio-console.h    |   19 -
 hw/virtio-pci.c        |   13 +-
 hw/virtio-serial-bus.c |  946 ++++++++++++++++++++++++++++++++++++++++++++++++
 hw/virtio-serial.c     |  151 ++++++++
 hw/virtio-serial.h     |  227 ++++++++++++
 hw/virtio.c            |    2 -
 hw/virtio.h            |    4 +-
 qemu-options.hx        |    4 +
 sysemu.h               |    6 -
 vl.c                   |   17 +-
 19 files changed, 1371 insertions(+), 218 deletions(-)
 delete mode 100644 hw/virtio-console.c
 delete mode 100644 hw/virtio-console.h
 create mode 100644 hw/virtio-serial-bus.c
 create mode 100644 hw/virtio-serial.c
 create mode 100644 hw/virtio-serial.h

[Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Amit Shah]

Hello,

This series addresses comments from last time:
- use ldl/stl instead of communicating in little endian.
- virtio-serial-bus is back in Makefile.target as a result of the above
  change.
- don't write to guest memory in handle_control_message
- is_console is a property; remove from custom debug output.
- reword FIXME comment for serial chardevs in qdev.c
- no need to maintain copy of guest_features

And a couple of other changes/bugfixes:
- Set serial ports to noncaching behaviour by default
- Ensure console input works in case of older kernel module
  (rebase artifact)

Obligatory disclaimer:
This series splits up the patches by functionality. Note, however,
that patches 2-6 introduce some functionality that's advertised to the
guest as having to work all at once or not at all. Also, the savevm
version is bumped only once but save/restore state is added in each of
the patches. They are split only for easier reviewability.

The older virtio-console.c file is completely removed and a new
virtio-serial.c is introduced so that reviewing is easier. I can send a
later patch to rename virtio-serial.c back to virtio-console.c.

Amit Shah (8):
  virtio: Remove duplicate macro definition for max. virtqueues, bump
    up the max
  virtio-console: qdev conversion, new virtio-serial-bus
  virtio-serial-bus: Maintain guest and host port open/close state
  virtio-serial-bus: Add a port 'name' property for port discovery in
    guests
  virtio-serial-bus: Add support for buffering guest output, throttling
    guests
  virtio-serial-bus: Add ability to hot-unplug ports
  virtio-serial: Add a 'virtserialport' device for generic serial port
    support
  Move virtio-serial to Makefile.hw

 Makefile.hw            |    2 +-
 Makefile.target        |    2 +-
 hw/pc.c                |   11 +-
 hw/ppc440_bamboo.c     |    7 -
 hw/qdev.c              |   10 +-
 hw/s390-virtio-bus.c   |   17 +-
 hw/s390-virtio-bus.h   |    2 +
 hw/s390-virtio.c       |    8 -
 hw/virtio-console.c    |  143 --------
 hw/virtio-console.h    |   19 -
 hw/virtio-pci.c        |   13 +-
 hw/virtio-serial-bus.c |  952 ++++++++++++++++++++++++++++++++++++++++++++++++
 hw/virtio-serial.c     |  151 ++++++++
 hw/virtio-serial.h     |  227 ++++++++++++
 hw/virtio.c            |    2 -
 hw/virtio.h            |    4 +-
 qemu-options.hx        |    4 +
 sysemu.h               |    6 -
 vl.c                   |   17 +-
 19 files changed, 1378 insertions(+), 219 deletions(-)
 delete mode 100644 hw/virtio-console.c
 delete mode 100644 hw/virtio-console.h
 create mode 100644 hw/virtio-serial-bus.c
 create mode 100644 hw/virtio-serial.c
 create mode 100644 hw/virtio-serial.h

[Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Amit Shah]

Hello people,

This iteration of the series removes the START and END flags (and
hence the header associated with each buffer). That's the major change
since the last submission.

Please review.

Obligatory disclaimer:
This series splits up the patches by functionality. Note, however,
that patches 2-6 introduce some functionality that's advertised to the
guest as having to work all at once or not at all. Also, the savevm
version is bumped only once but save/restore state is added in each of
the patches. They are split only for easier reviewability.

The older virtio-console.c file is completely removed and a new
virtio-serial.c is introduced so that reviewing is easier. I can send a
later patch to rename virtio-serial.c back to virtio-console.c.

Amit Shah (8):
  virtio: Remove duplicate macro definition for max. virtqueues, bump
    up the max
  virtio-console: qdev conversion, new virtio-serial-bus
  virtio-serial-bus: Maintain guest and host port open/close state
  virtio-serial-bus: Add a port 'name' property for port discovery in
    guests
  virtio-serial-bus: Add support for buffering guest output, throttling
    guests
  virtio-serial-bus: Add ability to hot-unplug ports
  virtio-serial: Add a 'virtserialport' device for generic serial port
    support
  Move virtio-serial to Makefile.objs

 Makefile.objs          |    2 +-
 Makefile.target        |    2 +-
 hw/pc.c                |   11 +-
 hw/ppc440_bamboo.c     |    7 -
 hw/qdev.c              |   10 +-
 hw/s390-virtio-bus.c   |   17 +-
 hw/s390-virtio-bus.h   |    2 +
 hw/s390-virtio.c       |    8 -
 hw/virtio-console.c    |  143 ---------
 hw/virtio-console.h    |   19 --
 hw/virtio-pci.c        |   13 +-
 hw/virtio-serial-bus.c |  788 ++++++++++++++++++++++++++++++++++++++++++++++++
 hw/virtio-serial.c     |  143 +++++++++
 hw/virtio-serial.h     |  199 ++++++++++++
 hw/virtio.c            |    2 -
 hw/virtio.h            |    4 +-
 qemu-options.hx        |    4 +
 sysemu.h               |    6 -
 vl.c                   |    2 +
 19 files changed, 1165 insertions(+), 217 deletions(-)
 delete mode 100644 hw/virtio-console.c
 delete mode 100644 hw/virtio-console.h
 create mode 100644 hw/virtio-serial-bus.c
 create mode 100644 hw/virtio-serial.c
 create mode 100644 hw/virtio-serial.h

Re: [Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Anthony Liguori]

On 01/14/2010 07:17 AM, Amit Shah wrote:
> Hello people,
>
> This iteration of the series removes the START and END flags (and
> hence the header associated with each buffer). That's the major change
> since the last submission.
>    

I think the biggest issue remaining is the buffering.

I think this is a pretty fundamental issue to work out since it 
determines the very nature of the transport (stream vs. datagram).

Because you have to put a max buffer size on the transport, I think 
buffering is a really flawed approach provably equivalent to just 
increasing the message size within the transport.  In general, the later 
is a better approach because then the guest is using it's memory vs. 
using host memory.

Regards,

Anthony Liguori

Re: [Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Amit Shah]

On (Thu) Jan 14 2010 [08:34:42], Anthony Liguori wrote:
> On 01/14/2010 07:17 AM, Amit Shah wrote:
>> Hello people,
>>
>> This iteration of the series removes the START and END flags (and
>> hence the header associated with each buffer). That's the major change
>> since the last submission.
>>    
>
> I think the biggest issue remaining is the buffering.
>
> I think this is a pretty fundamental issue to work out since it  
> determines the very nature of the transport (stream vs. datagram).

The buffering is done so that the guest copy of the buffer is acked so
that the guest can go about doing other things. (Currently the guest
spins till a buffer is acked by the host and waiting for individual
ports to flush their data to whichever receiver will consume some time.)

This also puts buffer management in one place: not all ports will
consume all the data given to them. There's a need to maintain the
buffer contents till the ports consume all the data. This buffer
management can either be done by the individual ports, or it could be
done by the bus code. I prefer doing it in the bus code since the code
will be the same and be in one place instead of each port doing it
separately all around the place.

> Because you have to put a max buffer size on the transport, I think  
> buffering is a really flawed approach provably equivalent to just  
> increasing the message size within the transport.  In general, the later  
> is a better approach because then the guest is using it's memory vs.  
> using host memory.

OK; alternative solutions on how to handle this?

		Amit

Re: [Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Anthony Liguori]

On 01/14/2010 09:34 AM, Amit Shah wrote:
> On (Thu) Jan 14 2010 [08:34:42], Anthony Liguori wrote:
>    
>> On 01/14/2010 07:17 AM, Amit Shah wrote:
>>      
>>> Hello people,
>>>
>>> This iteration of the series removes the START and END flags (and
>>> hence the header associated with each buffer). That's the major change
>>> since the last submission.
>>>
>>>        
>> I think the biggest issue remaining is the buffering.
>>
>> I think this is a pretty fundamental issue to work out since it
>> determines the very nature of the transport (stream vs. datagram).
>>      
> The buffering is done so that the guest copy of the buffer is acked so
> that the guest can go about doing other things. (Currently the guest
> spins till a buffer is acked by the host and waiting for individual
> ports to flush their data to whichever receiver will consume some time.)
>    

The guest already gets an ack when data is consumed.  The host adds the 
consumed buffer to the used ring.

> This also puts buffer management in one place: not all ports will
> consume all the data given to them. There's a need to maintain the
> buffer contents till the ports consume all the data. This buffer
> management can either be done by the individual ports, or it could be
> done by the bus code. I prefer doing it in the bus code since the code
> will be the same and be in one place instead of each port doing it
> separately all around the place.
>    

The rings themselves are buffers.  Since each port has a ring, each port 
has independent buffering right now.

Regards,

Anthony Liguori

Re: [Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Jamie Lokier]

Anthony Liguori wrote:
> I think this is a pretty fundamental issue to work out since it 
> determines the very nature of the transport (stream vs. datagram).

For the record, I don't think there's anything _wrong_ with a datagram
transport.  It would be quite useful sometimes.  But if there is
datagram support, it should be optional, just like you can choose
between SOCK_STREAM and SOCK_DGRAM for AF_UNIX sockets.

Something else occurred to me with the cut buffer application:

What happens if the guest crashes, kexecs or whatever when it's half
way through sending a cut buffer?  A stream protocol will not have a
nice way to recover from that unless there is an additional "out of
band" way to say "I'm starting again".  Does virtio-serial have an
"I'm starting again" which is passed to the host side application?

> Because you have to put a max buffer size on the transport, I think 
> buffering is a really flawed approach provably equivalent to just 
> increasing the message size within the transport.  In general, the later 
> is a better approach because then the guest is using it's memory vs. 
> using host memory.

I agree, using guest memory for the buffer also means there doesn't
have to be an arbitrary limit on the buffer size, or a time limit.  It
can just wait there until it's consumed or the guest decides to restart.

-- Jamie

Re: [Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Amit Shah]

On (Tue) Jan 19 2010 [17:59:33], Jamie Lokier wrote:
> 
> What happens if the guest crashes, kexecs or whatever when it's half
> way through sending a cut buffer?  A stream protocol will not have a
> nice way to recover from that unless there is an additional "out of
> band" way to say "I'm starting again".  Does virtio-serial have an
> "I'm starting again" which is passed to the host side application?

That's what I meant when I was talking about the START and END
delimiters. I've removed those for now though. Something like what you
suggest can be added later on.

		Amit

[Qemu-devel] [PATCH 0/8] virtio-console: Move to qdev, multiple devices, generic ports

[Amit Shah]

Hello all,

In this series I've removed the buffering that happened in the host
and ack the amount of data that ports actually consume. This basically
removes the older patch 5/8 that introduced buffering and throttling.

Other changes include addition of patch 8: MSI support and ensuring we
don't crash in the event we don't have chardevs opened and guest
writes out to virtio-consoles.

Obligatory disclaimer:
This series splits up the patches by functionality. Note, however,
that patches 2-5 introduce some functionality that's advertised to the
guest as having to work all at once or not at all. Also, the savevm
version is bumped only once but save/restore state is added in each of
the patches. They are split only for easier reviewability.

The older virtio-console.c file is completely removed and a new
virtio-serial.c is introduced so that reviewing is easier. I can send a
later patch to rename virtio-serial.c back to virtio-console.c.


Amit Shah (8):
  virtio: Remove duplicate macro definition for max. virtqueues, bump
    up the max
  virtio-console: qdev conversion, new virtio-serial-bus
  virtio-serial-bus: Maintain guest and host port open/close state
  virtio-serial-bus: Add a port 'name' property for port discovery in
    guests
  virtio-serial-bus: Add ability to hot-unplug ports
  virtio-serial: Add a 'virtserialport' device for generic serial port
    support
  Move virtio-serial to Makefile.objs
  virtio-serial: Use MSI vectors for port virtqueues

 Makefile.objs          |    2 +-
 Makefile.target        |    2 +-
 hw/pc.c                |   11 +-
 hw/ppc440_bamboo.c     |    7 -
 hw/qdev.c              |   10 +-
 hw/s390-virtio-bus.c   |   17 +-
 hw/s390-virtio-bus.h   |    2 +
 hw/s390-virtio.c       |    8 -
 hw/virtio-console.c    |  143 -----------
 hw/virtio-console.h    |   19 --
 hw/virtio-pci.c        |   17 +-
 hw/virtio-serial-bus.c |  620 ++++++++++++++++++++++++++++++++++++++++++++++++
 hw/virtio-serial.c     |  146 ++++++++++++
 hw/virtio-serial.h     |  173 ++++++++++++++
 hw/virtio.c            |    2 -
 hw/virtio.h            |    4 +-
 qemu-options.hx        |    4 +
 sysemu.h               |    6 -
 vl.c                   |    2 +
 19 files changed, 978 insertions(+), 217 deletions(-)
 delete mode 100644 hw/virtio-console.c
 delete mode 100644 hw/virtio-console.h
 create mode 100644 hw/virtio-serial-bus.c
 create mode 100644 hw/virtio-serial.c
 create mode 100644 hw/virtio-serial.h

[Qemu-devel] [PATCH 1/8] virtio: Remove duplicate macro definition for max. virtqueues, bump up the max

[Amit Shah]

VIRTIO_PCI_QUEUE_MAX is redefined in hw/virtio.c. Let's just keep it in
hw/virtio.h.

Also, bump up the value of the maximum allowed virtqueues to 64. This is
in preparation to allow multiple ports per virtio-console device.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio.c |    2 --
 hw/virtio.h |    2 +-
 2 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/hw/virtio.c b/hw/virtio.c
index fa7184a..7c020a3 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -75,8 +75,6 @@ struct VirtQueue
     void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq);
 };
 
-#define VIRTIO_PCI_QUEUE_MAX        16
-
 /* virt queue functions */
 static void virtqueue_init(VirtQueue *vq)
 {
diff --git a/hw/virtio.h b/hw/virtio.h
index 3994cc9..7b2b327 100644
--- a/hw/virtio.h
+++ b/hw/virtio.h
@@ -90,7 +90,7 @@ typedef struct {
     unsigned (*get_features)(void * opaque);
 } VirtIOBindings;
 
-#define VIRTIO_PCI_QUEUE_MAX 16
+#define VIRTIO_PCI_QUEUE_MAX 64
 
 #define VIRTIO_NO_VECTOR 0xffff
 
-- 
1.6.2.5

[Qemu-devel] [PATCH 2/8] virtio-console: qdev conversion, new virtio-serial-bus

[Amit Shah]

This commit converts the virtio-console device to create a new
virtio-serial bus that can host console and generic serial ports. The
file hosting this code is now called virtio-serial-bus.c.

The virtio console is now a very simple qdev device that sits on the
virtio-serial-bus and communicates between the bus and qemu's chardevs.

This commit also includes a few changes to the virtio backing code for
pci and s390 to spawn the virtio-serial bus.

As a result of the qdev conversion, we get rid of a lot of legacy code.
The old-style way of instantiating a virtio console using

    -virtioconsole ...

is maintained, but the new, preferred way is to use

    -device virtio-serial -device virtconsole,chardev=...

With this commit, multiple devices as well as multiple ports with a
single device can be supported.

For multiple ports support, each port gets an IO vq pair. Since the
guest needs to know in advance how many vqs a particular device will
need, we have to set this number as a property of the virtio-serial
device and also as a config option.

In addition, we also spawn a pair of control IO vqs. This is an internal
channel meant for guest-host communication for things like port
open/close, sending port properties over to the guest, etc.

This commit is a part of a series of other commits to get the full
implementation of multiport support. Future commits will add other
support as well as ride on the savevm version that we bump up here.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 Makefile.target        |    2 +-
 hw/pc.c                |   11 +-
 hw/ppc440_bamboo.c     |    7 -
 hw/qdev.c              |   10 +-
 hw/s390-virtio-bus.c   |   17 +-
 hw/s390-virtio-bus.h   |    2 +
 hw/s390-virtio.c       |    8 -
 hw/virtio-console.c    |  143 --------------
 hw/virtio-console.h    |   19 --
 hw/virtio-pci.c        |   13 +-
 hw/virtio-serial-bus.c |  507 ++++++++++++++++++++++++++++++++++++++++++++++++
 hw/virtio-serial.c     |  111 +++++++++++
 hw/virtio-serial.h     |  158 +++++++++++++++
 hw/virtio.h            |    2 +-
 qemu-options.hx        |    4 +
 sysemu.h               |    6 -
 vl.c                   |    2 +
 17 files changed, 809 insertions(+), 213 deletions(-)
 delete mode 100644 hw/virtio-console.c
 delete mode 100644 hw/virtio-console.h
 create mode 100644 hw/virtio-serial-bus.c
 create mode 100644 hw/virtio-serial.c
 create mode 100644 hw/virtio-serial.h

diff --git a/Makefile.target b/Makefile.target
index e661478..60df16d 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -172,7 +172,7 @@ ifdef CONFIG_SOFTMMU
 obj-y = vl.o async.o monitor.o pci.o pci_host.o pcie_host.o machine.o gdbstub.o
 # virtio has to be here due to weird dependency between PCI and virtio-net.
 # need to fix this properly
-obj-y += virtio-blk.o virtio-balloon.o virtio-net.o virtio-console.o virtio-pci.o
+obj-y += virtio-blk.o virtio-balloon.o virtio-net.o virtio-serial.o virtio-serial-bus.o virtio-pci.o
 obj-$(CONFIG_KVM) += kvm.o kvm-all.o
 obj-$(CONFIG_ISA_MMIO) += isa_mmio.o
 LIBS+=-lz
diff --git a/hw/pc.c b/hw/pc.c
index a93c5f2..3aadfa9 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -1018,15 +1018,6 @@ static void pc_init1(ram_addr_t ram_size,
             pci_create_simple(pci_bus, -1, "lsi53c895a");
         }
     }
-
-    /* Add virtio console devices */
-    if (pci_enabled) {
-        for(i = 0; i < MAX_VIRTIO_CONSOLES; i++) {
-            if (virtcon_hds[i]) {
-                pci_create_simple(pci_bus, -1, "virtio-console-pci");
-            }
-        }
-    }
 }
 
 static void pc_init_pci(ram_addr_t ram_size,
@@ -1102,7 +1093,7 @@ static QEMUMachine pc_machine_v0_10 = {
             .property = "class",
             .value    = stringify(PCI_CLASS_STORAGE_OTHER),
         },{
-            .driver   = "virtio-console-pci",
+            .driver   = "virtio-serial-pci",
             .property = "class",
             .value    = stringify(PCI_CLASS_DISPLAY_OTHER),
         },{
diff --git a/hw/ppc440_bamboo.c b/hw/ppc440_bamboo.c
index a488240..1ab9872 100644
--- a/hw/ppc440_bamboo.c
+++ b/hw/ppc440_bamboo.c
@@ -108,13 +108,6 @@ static void bamboo_init(ram_addr_t ram_size,
     env = ppc440ep_init(&ram_size, &pcibus, pci_irq_nrs, 1, cpu_model);
 
     if (pcibus) {
-        /* Add virtio console devices */
-        for(i = 0; i < MAX_VIRTIO_CONSOLES; i++) {
-            if (virtcon_hds[i]) {
-                pci_create_simple(pcibus, -1, "virtio-console-pci");
-            }
-        }
-
         /* Register network interfaces. */
         for (i = 0; i < nb_nics; i++) {
             /* There are no PCI NICs on the Bamboo board, but there are
diff --git a/hw/qdev.c b/hw/qdev.c
index b6bd4ae..c643576 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -321,13 +321,9 @@ void qdev_machine_creation_done(void)
 CharDriverState *qdev_init_chardev(DeviceState *dev)
 {
     static int next_serial;
-    static int next_virtconsole;
-    /* FIXME: This is a nasty hack that needs to go away.  */
-    if (strncmp(dev->info->name, "virtio", 6) == 0) {
-        return virtcon_hds[next_virtconsole++];
-    } else {
-        return serial_hds[next_serial++];
-    }
+
+    /* FIXME: This function needs to go away: use chardev properties!  */
+    return serial_hds[next_serial++];
 }
 
 BusState *qdev_get_parent_bus(DeviceState *dev)
diff --git a/hw/s390-virtio-bus.c b/hw/s390-virtio-bus.c
index 980e7eb..6b6dafc 100644
--- a/hw/s390-virtio-bus.c
+++ b/hw/s390-virtio-bus.c
@@ -26,7 +26,7 @@
 #include "loader.h"
 #include "elf.h"
 #include "hw/virtio.h"
-#include "hw/virtio-console.h"
+#include "hw/virtio-serial.h"
 #include "hw/sysbus.h"
 #include "kvm.h"
 
@@ -131,7 +131,7 @@ static int s390_virtio_blk_init(VirtIOS390Device *dev)
     return s390_virtio_device_init(dev, vdev);
 }
 
-static int s390_virtio_console_init(VirtIOS390Device *dev)
+static int s390_virtio_serial_init(VirtIOS390Device *dev)
 {
     VirtIOS390Bus *bus;
     VirtIODevice *vdev;
@@ -139,7 +139,7 @@ static int s390_virtio_console_init(VirtIOS390Device *dev)
 
     bus = DO_UPCAST(VirtIOS390Bus, bus, dev->qdev.parent_bus);
 
-    vdev = virtio_console_init((DeviceState *)dev);
+    vdev = virtio_serial_init((DeviceState *)dev, dev->max_virtserial_ports);
     if (!vdev) {
         return -1;
     }
@@ -342,11 +342,14 @@ static VirtIOS390DeviceInfo s390_virtio_blk = {
     },
 };
 
-static VirtIOS390DeviceInfo s390_virtio_console = {
-    .init = s390_virtio_console_init,
-    .qdev.name = "virtio-console-s390",
+static VirtIOS390DeviceInfo s390_virtio_serial = {
+    .init = s390_virtio_serial_init,
+    .qdev.name = "virtio-serial-s390",
+    .qdev.alias = "virtio-serial",
     .qdev.size = sizeof(VirtIOS390Device),
     .qdev.props = (Property[]) {
+        DEFINE_PROP_UINT32("max_ports", VirtIOS390Device, max_virtserial_ports,
+                           31),
         DEFINE_PROP_END_OF_LIST(),
     },
 };
@@ -370,7 +373,7 @@ static void s390_virtio_bus_register_withprop(VirtIOS390DeviceInfo *info)
 
 static void s390_virtio_register(void)
 {
-    s390_virtio_bus_register_withprop(&s390_virtio_console);
+    s390_virtio_bus_register_withprop(&s390_virtio_serial);
     s390_virtio_bus_register_withprop(&s390_virtio_blk);
     s390_virtio_bus_register_withprop(&s390_virtio_net);
 }
diff --git a/hw/s390-virtio-bus.h b/hw/s390-virtio-bus.h
index 8ae2065..8e4763a 100644
--- a/hw/s390-virtio-bus.h
+++ b/hw/s390-virtio-bus.h
@@ -41,6 +41,8 @@ typedef struct VirtIOS390Device {
     DriveInfo *dinfo;
     NICConf nic;
     uint32_t host_features;
+    /* Max. number of ports we can have for a the virtio-serial device */
+    uint32_t max_virtserial_ports;
 } VirtIOS390Device;
 
 typedef struct VirtIOS390Bus {
diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
index 0fa6ba6..3582728 100644
--- a/hw/s390-virtio.c
+++ b/hw/s390-virtio.c
@@ -26,7 +26,6 @@
 #include "loader.h"
 #include "elf.h"
 #include "hw/virtio.h"
-#include "hw/virtio-console.h"
 #include "hw/sysbus.h"
 #include "kvm.h"
 
@@ -207,13 +206,6 @@ static void s390_init(ram_addr_t ram_size,
                                strlen(kernel_cmdline), 1);
     }
 
-    /* Create VirtIO console */
-    for(i = 0; i < MAX_VIRTIO_CONSOLES; i++) {
-        if (virtcon_hds[i]) {
-            qdev_init_nofail(qdev_create((BusState *)s390_bus, "virtio-console-s390"));
-        }
-    }
-
     /* Create VirtIO network adapters */
     for(i = 0; i < nb_nics; i++) {
         NICInfo *nd = &nd_table[i];
diff --git a/hw/virtio-console.c b/hw/virtio-console.c
deleted file mode 100644
index 4f18ef2..0000000
--- a/hw/virtio-console.c
+++ /dev/null
@@ -1,143 +0,0 @@
-/*
- * Virtio Console Device
- *
- * Copyright IBM, Corp. 2008
- *
- * Authors:
- *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2.  See
- * the COPYING file in the top-level directory.
- *
- */
-
-#include "hw.h"
-#include "qemu-char.h"
-#include "virtio.h"
-#include "virtio-console.h"
-
-
-typedef struct VirtIOConsole
-{
-    VirtIODevice vdev;
-    VirtQueue *ivq, *ovq;
-    CharDriverState *chr;
-} VirtIOConsole;
-
-static VirtIOConsole *to_virtio_console(VirtIODevice *vdev)
-{
-    return (VirtIOConsole *)vdev;
-}
-
-static void virtio_console_handle_output(VirtIODevice *vdev, VirtQueue *vq)
-{
-    VirtIOConsole *s = to_virtio_console(vdev);
-    VirtQueueElement elem;
-
-    while (virtqueue_pop(vq, &elem)) {
-        ssize_t len = 0;
-        int d;
-
-        for (d = 0; d < elem.out_num; d++) {
-            len += qemu_chr_write(s->chr, (uint8_t *)elem.out_sg[d].iov_base,
-                                  elem.out_sg[d].iov_len);
-        }
-        virtqueue_push(vq, &elem, len);
-        virtio_notify(vdev, vq);
-    }
-}
-
-static void virtio_console_handle_input(VirtIODevice *vdev, VirtQueue *vq)
-{
-}
-
-static uint32_t virtio_console_get_features(VirtIODevice *vdev, uint32_t f)
-{
-    return f;
-}
-
-static int vcon_can_read(void *opaque)
-{
-    VirtIOConsole *s = (VirtIOConsole *) opaque;
-
-    if (!virtio_queue_ready(s->ivq) ||
-        !(s->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
-        virtio_queue_empty(s->ivq))
-        return 0;
-
-    /* current implementations have a page sized buffer.
-     * We fall back to a one byte per read if there is not enough room.
-     * It would be cool to have a function that returns the available byte
-     * instead of checking for a limit */
-    if (virtqueue_avail_bytes(s->ivq, TARGET_PAGE_SIZE, 0))
-        return TARGET_PAGE_SIZE;
-    if (virtqueue_avail_bytes(s->ivq, 1, 0))
-        return 1;
-    return 0;
-}
-
-static void vcon_read(void *opaque, const uint8_t *buf, int size)
-{
-    VirtIOConsole *s = (VirtIOConsole *) opaque;
-    VirtQueueElement elem;
-    int offset = 0;
-
-    /* The current kernel implementation has only one outstanding input
-     * buffer of PAGE_SIZE. Nevertheless, this function is prepared to
-     * handle multiple buffers with multiple sg element for input */
-    while (offset < size) {
-        int i = 0;
-        if (!virtqueue_pop(s->ivq, &elem))
-                break;
-        while (offset < size && i < elem.in_num) {
-            int len = MIN(elem.in_sg[i].iov_len, size - offset);
-            memcpy(elem.in_sg[i].iov_base, buf + offset, len);
-            offset += len;
-            i++;
-        }
-        virtqueue_push(s->ivq, &elem, size);
-    }
-    virtio_notify(&s->vdev, s->ivq);
-}
-
-static void vcon_event(void *opaque, int event)
-{
-    /* we will ignore any event for the time being */
-}
-
-static void virtio_console_save(QEMUFile *f, void *opaque)
-{
-    VirtIOConsole *s = opaque;
-
-    virtio_save(&s->vdev, f);
-}
-
-static int virtio_console_load(QEMUFile *f, void *opaque, int version_id)
-{
-    VirtIOConsole *s = opaque;
-
-    if (version_id != 1)
-        return -EINVAL;
-
-    virtio_load(&s->vdev, f);
-    return 0;
-}
-
-VirtIODevice *virtio_console_init(DeviceState *dev)
-{
-    VirtIOConsole *s;
-    s = (VirtIOConsole *)virtio_common_init("virtio-console",
-                                            VIRTIO_ID_CONSOLE,
-                                            0, sizeof(VirtIOConsole));
-    s->vdev.get_features = virtio_console_get_features;
-
-    s->ivq = virtio_add_queue(&s->vdev, 128, virtio_console_handle_input);
-    s->ovq = virtio_add_queue(&s->vdev, 128, virtio_console_handle_output);
-
-    s->chr = qdev_init_chardev(dev);
-    qemu_chr_add_handlers(s->chr, vcon_can_read, vcon_read, vcon_event, s);
-
-    register_savevm("virtio-console", -1, 1, virtio_console_save, virtio_console_load, s);
-
-    return &s->vdev;
-}
diff --git a/hw/virtio-console.h b/hw/virtio-console.h
deleted file mode 100644
index 84d0717..0000000
--- a/hw/virtio-console.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/*
- * Virtio Console Support
- *
- * Copyright IBM, Corp. 2008
- *
- * Authors:
- *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2.  See
- * the COPYING file in the top-level directory.
- *
- */
-#ifndef _QEMU_VIRTIO_CONSOLE_H
-#define _QEMU_VIRTIO_CONSOLE_H
-
-/* The ID for virtio console */
-#define VIRTIO_ID_CONSOLE 3
-
-#endif
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 573c98a..e7fabfb 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -95,6 +95,8 @@ typedef struct {
     DriveInfo *dinfo;
     NICConf nic;
     uint32_t host_features;
+    /* Max. number of ports we can have for a the virtio-serial device */
+    uint32_t max_virtserial_ports;
 } VirtIOPCIProxy;
 
 /* virtio device */
@@ -483,7 +485,7 @@ static int virtio_blk_exit_pci(PCIDevice *pci_dev)
     return virtio_exit_pci(pci_dev);
 }
 
-static int virtio_console_init_pci(PCIDevice *pci_dev)
+static int virtio_serial_init_pci(PCIDevice *pci_dev)
 {
     VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);
     VirtIODevice *vdev;
@@ -493,7 +495,7 @@ static int virtio_console_init_pci(PCIDevice *pci_dev)
         proxy->class_code != PCI_CLASS_OTHERS)          /* qemu-kvm  */
         proxy->class_code = PCI_CLASS_COMMUNICATION_OTHER;
 
-    vdev = virtio_console_init(&pci_dev->qdev);
+    vdev = virtio_serial_init(&pci_dev->qdev, proxy->max_virtserial_ports);
     if (!vdev) {
         return -1;
     }
@@ -573,13 +575,16 @@ static PCIDeviceInfo virtio_info[] = {
         },
         .qdev.reset = virtio_pci_reset,
     },{
-        .qdev.name = "virtio-console-pci",
+        .qdev.name = "virtio-serial-pci",
+        .qdev.alias = "virtio-serial",
         .qdev.size = sizeof(VirtIOPCIProxy),
-        .init      = virtio_console_init_pci,
+        .init      = virtio_serial_init_pci,
         .exit      = virtio_exit_pci,
         .qdev.props = (Property[]) {
             DEFINE_PROP_HEX32("class", VirtIOPCIProxy, class_code, 0),
             DEFINE_VIRTIO_COMMON_FEATURES(VirtIOPCIProxy, host_features),
+            DEFINE_PROP_UINT32("max_ports", VirtIOPCIProxy, max_virtserial_ports,
+                               31),
             DEFINE_PROP_END_OF_LIST(),
         },
         .qdev.reset = virtio_pci_reset,
diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
new file mode 100644
index 0000000..e8bbd7d
--- /dev/null
+++ b/hw/virtio-serial-bus.c
@@ -0,0 +1,507 @@
+/*
+ * A bus for connecting virtio serial and console ports
+ *
+ * Copyright (C) 2009 Red Hat, Inc.
+ *
+ * Author(s):
+ *  Amit Shah <amit.shah@redhat.com>
+ *
+ * Some earlier parts are:
+ *  Copyright IBM, Corp. 2008
+ * authored by
+ *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "monitor.h"
+#include "qemu-queue.h"
+#include "sysbus.h"
+#include "virtio-serial.h"
+
+/* The virtio-serial bus on top of which the ports will ride as devices */
+struct VirtIOSerialBus {
+    BusState qbus;
+
+    /* This is the parent device that provides the bus for ports. */
+    VirtIOSerial *vser;
+
+    /* The maximum number of ports that can ride on top of this bus */
+    uint32_t max_nr_ports;
+};
+
+struct VirtIOSerial {
+    VirtIODevice vdev;
+
+    VirtQueue *c_ivq, *c_ovq;
+    /* Arrays of ivqs and ovqs: one per port */
+    VirtQueue **ivqs, **ovqs;
+
+    VirtIOSerialBus *bus;
+
+    QTAILQ_HEAD(, VirtIOSerialPort) ports;
+    struct virtio_console_config config;
+};
+
+static VirtIOSerialPort *find_port_by_id(VirtIOSerial *vser, uint32_t id)
+{
+    VirtIOSerialPort *port;
+
+    QTAILQ_FOREACH(port, &vser->ports, next) {
+        if (port->id == id)
+            return port;
+    }
+    return NULL;
+}
+
+static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
+{
+    VirtIOSerialPort *port;
+
+    QTAILQ_FOREACH(port, &vser->ports, next) {
+        if (port->ivq == vq || port->ovq == vq)
+            return port;
+    }
+    return NULL;
+}
+
+static size_t write_to_port(VirtIOSerialPort *port,
+                            const uint8_t *buf, size_t size)
+{
+    VirtQueueElement elem;
+    VirtQueue *vq;
+    size_t offset = 0;
+    size_t len = 0;
+
+    vq = port->ivq;
+    if (!virtio_queue_ready(vq)) {
+        return 0;
+    }
+    if (!size) {
+        return 0;
+    }
+
+    while (offset < size) {
+        int i;
+
+        if (!virtqueue_pop(vq, &elem)) {
+            break;
+        }
+
+        for (i = 0; offset < size && i < elem.in_num; i++) {
+            len = MIN(elem.in_sg[i].iov_len, size - offset);
+
+            memcpy(elem.in_sg[i].iov_base, buf + offset, len);
+            offset += len;
+        }
+        virtqueue_push(vq, &elem, len);
+    }
+
+    virtio_notify(&port->vser->vdev, vq);
+    return offset;
+}
+
+static size_t send_control_msg(VirtIOSerialPort *port, void *buf, size_t len)
+{
+    VirtQueueElement elem;
+    VirtQueue *vq;
+    struct virtio_console_control *cpkt;
+
+    vq = port->vser->c_ivq;
+    if (!virtio_queue_ready(vq)) {
+        return 0;
+    }
+    if (!virtqueue_pop(vq, &elem)) {
+        return 0;
+    }
+
+    cpkt = (struct virtio_console_control *)buf;
+    stl_p(&cpkt->id, port->id);
+    memcpy(elem.in_sg[0].iov_base, buf, len);
+
+    virtqueue_push(vq, &elem, len);
+    virtio_notify(&port->vser->vdev, vq);
+    return len;
+}
+
+static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,
+                                 uint16_t value)
+{
+    struct virtio_console_control cpkt;
+
+    stw_p(&cpkt.event, event);
+    stw_p(&cpkt.value, value);
+
+    return send_control_msg(port, &cpkt, sizeof(cpkt));
+}
+
+/* Functions for use inside qemu to open and read from/write to ports */
+int virtio_serial_open(VirtIOSerialPort *port)
+{
+    return 0;
+}
+
+int virtio_serial_close(VirtIOSerialPort *port)
+{
+    return 0;
+}
+
+/* Individual ports/apps call this function to write to the guest. */
+ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
+                            size_t size)
+{
+    return write_to_port(port, buf, size);
+}
+
+/*
+ * Readiness of the guest to accept data on a port.
+ * Returns max. data the guest can receive
+ */
+size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
+{
+    VirtQueue *vq = port->ivq;
+
+    if (!virtio_queue_ready(vq) ||
+        !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
+        virtio_queue_empty(vq)) {
+        return 0;
+    }
+
+    if (virtqueue_avail_bytes(vq, 4096, 0)) {
+        return 4096;
+    }
+    if (virtqueue_avail_bytes(vq, 1, 0)) {
+        return 1;
+    }
+    return 0;
+}
+
+/* Guest wants to notify us of some event */
+static void handle_control_message(VirtIOSerial *vser, void *buf)
+{
+    struct VirtIOSerialPort *port;
+    struct virtio_console_control cpkt, *gcpkt;
+
+    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);
+
+    switch(cpkt.event) {
+    case VIRTIO_CONSOLE_PORT_READY:
+        /*
+         * Now that we know the guest asked for the port name, we're
+         * sure the guest has initialised whatever state is necessary
+         * for this port. Now's a good time to let the guest know if
+         * this port is a console port so that the guest can hook it
+         * up to hvc.
+         */
+        if (port->is_console) {
+            send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
+        }
+        /*
+         * When the guest has asked us for this information it means
+         * the guest is all setup and has its virtqueues
+         * initialised. If some app is interested in knowing about
+         * this event, let it know.
+         */
+        if (port->info->guest_ready) {
+            port->info->guest_ready(port);
+        }
+        break;
+    }
+}
+
+static void control_in(VirtIODevice *vdev, VirtQueue *vq)
+{
+}
+
+static void control_out(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtQueueElement elem;
+    VirtIOSerial *vser;
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+
+    while (virtqueue_pop(vq, &elem)) {
+        handle_control_message(vser, elem.out_sg[0].iov_base);
+        virtqueue_push(vq, &elem, elem.out_sg[0].iov_len);
+    }
+    virtio_notify(vdev, vq);
+}
+
+/* Guest wrote something to some port. */
+static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIOSerial *vser;
+    VirtQueueElement elem;
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+
+    while (virtqueue_pop(vq, &elem)) {
+        VirtIOSerialPort *port;
+        size_t ret;
+
+        port = find_port_by_vq(vser, vq);
+        if (!port) {
+            ret = 0;
+            goto next_buf;
+        }
+
+        /*
+         * A port may not have any handler registered for consuming the
+         * data that the guest sends or it may not have a chardev associated
+         * with it. Just ignore the data in that case.
+         */
+        if (!port->info->have_data) {
+            ret = 0;
+            goto next_buf;
+        }
+
+        /* The guest always sends only one sg */
+        ret = port->info->have_data(port, elem.out_sg[0].iov_base,
+                                    elem.out_sg[0].iov_len);
+
+    next_buf:
+        virtqueue_push(vq, &elem, ret);
+    }
+    virtio_notify(vdev, vq);
+}
+
+static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
+{
+}
+
+static uint32_t get_features(VirtIODevice *vdev, uint32_t features)
+{
+    features |= (1 << VIRTIO_CONSOLE_F_MULTIPORT);
+
+    return features;
+}
+
+/* Guest requested config info */
+static void get_config(VirtIODevice *vdev, uint8_t *config_data)
+{
+    VirtIOSerial *vser;
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+    memcpy(config_data, &vser->config, sizeof(struct virtio_console_config));
+}
+
+static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
+{
+    struct virtio_console_config config;
+
+    memcpy(&config, config_data, sizeof(config));
+}
+
+static void virtio_serial_save(QEMUFile *f, void *opaque)
+{
+    VirtIOSerial *s = opaque;
+
+    /* The virtio device */
+    virtio_save(&s->vdev, f);
+
+    /* 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);
+}
+
+static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
+{
+    VirtIOSerial *s = opaque;
+
+    if (version_id > 2) {
+        return -EINVAL;
+    }
+    /* The virtio device */
+    virtio_load(&s->vdev, f);
+
+    if (version_id < 2) {
+        return 0;
+    }
+
+    /* The config space */
+    qemu_get_be16s(f, &s->config.cols);
+    qemu_get_be16s(f, &s->config.rows);
+    s->config.nr_ports = qemu_get_be32(f);
+
+    return 0;
+}
+
+static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
+
+static struct BusInfo virtser_bus_info = {
+    .name      = "virtio-serial-bus",
+    .size      = sizeof(VirtIOSerialBus),
+    .print_dev = virtser_bus_dev_print,
+};
+
+static VirtIOSerialBus *virtser_bus_new(DeviceState *dev)
+{
+    VirtIOSerialBus *bus;
+
+    bus = FROM_QBUS(VirtIOSerialBus, qbus_create(&virtser_bus_info, dev,
+                                                 "virtio-serial-bus"));
+    bus->qbus.allow_hotplug = 1;
+
+    return bus;
+}
+
+static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
+{
+    VirtIOSerialDevice *dev = DO_UPCAST(VirtIOSerialDevice, qdev, qdev);
+    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);
+
+    monitor_printf(mon, "%*s dev-prop-int: id: %u\n",
+                   indent, "", port->id);
+}
+
+static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
+{
+    VirtIOSerialDevice *dev = DO_UPCAST(VirtIOSerialDevice, qdev, qdev);
+    VirtIOSerialPortInfo *info = DO_UPCAST(VirtIOSerialPortInfo, qdev, base);
+    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);
+    VirtIOSerialBus *bus = DO_UPCAST(VirtIOSerialBus, qbus, qdev->parent_bus);
+    int ret;
+    bool plugging_port0;
+
+    port->vser = bus->vser;
+
+    /*
+     * Is the first console port we're seeing? If so, put it up at
+     * location 0. This is done for backward compatibility (old
+     * kernel, new qemu).
+     */
+    plugging_port0 = port->is_console && !find_port_by_id(port->vser, 0);
+
+    if (port->vser->config.nr_ports == bus->max_nr_ports && !plugging_port0) {
+        qemu_error("virtio-serial-bus: Maximum device limit reached\n");
+        return -1;
+    }
+    dev->info = info;
+
+    ret = info->init(dev);
+    if (ret) {
+        return ret;
+    }
+
+    port->id = plugging_port0 ? 0 : port->vser->config.nr_ports++;
+
+    QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
+    port->ivq = port->vser->ivqs[port->id];
+    port->ovq = port->vser->ovqs[port->id];
+
+    /* Send an update to the guest about this new port added */
+    virtio_notify_config(&port->vser->vdev);
+
+    return ret;
+}
+
+static int virtser_port_qdev_exit(DeviceState *qdev)
+{
+    VirtIOSerialDevice *dev = DO_UPCAST(VirtIOSerialDevice, qdev, qdev);
+    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);
+    VirtIOSerial *vser = port->vser;
+
+    /*
+     * 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)
+        port->info->exit(dev);
+
+    return 0;
+}
+
+void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info)
+{
+    info->qdev.init = virtser_port_qdev_init;
+    info->qdev.bus_info = &virtser_bus_info;
+    info->qdev.exit = virtser_port_qdev_exit;
+    info->qdev.unplug = qdev_simple_unplug_cb;
+    qdev_register(&info->qdev);
+}
+
+VirtIODevice *virtio_serial_init(DeviceState *dev, uint32_t max_nr_ports)
+{
+    VirtIOSerial *vser;
+    VirtIODevice *vdev;
+    uint32_t i;
+
+    if (!max_nr_ports)
+        return NULL;
+
+    vdev = virtio_common_init("virtio-serial", VIRTIO_ID_CONSOLE,
+                              sizeof(struct virtio_console_config),
+                              sizeof(VirtIOSerial));
+
+    vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
+
+    /* Spawn a new virtio-serial bus on which the ports will ride as devices */
+    vser->bus = virtser_bus_new(dev);
+    vser->bus->vser = vser;
+    QTAILQ_INIT(&vser->ports);
+
+    vser->bus->max_nr_ports = max_nr_ports;
+    vser->ivqs = qemu_malloc(max_nr_ports * sizeof(VirtQueue *));
+    vser->ovqs = qemu_malloc(max_nr_ports * sizeof(VirtQueue *));
+
+    /* Add a queue for host to guest transfers for port 0 (backward compat) */
+    vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
+    /* Add a queue for guest to host transfers for port 0 (backward compat) */
+    vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
+
+    /* control queue: host to guest */
+    vser->c_ivq = virtio_add_queue(vdev, 16, control_in);
+    /* control queue: guest to host */
+    vser->c_ovq = virtio_add_queue(vdev, 16, control_out);
+
+    for (i = 1; i < vser->bus->max_nr_ports; i++) {
+        /* Add a per-port queue for host to guest transfers */
+        vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
+        /* Add a per-per queue for guest to host transfers */
+        vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
+    }
+
+    vser->config.max_nr_ports = max_nr_ports;
+    /*
+     * Reserve location 0 for a console port for backward compat
+     * (old kernel, new qemu)
+     */
+    vser->config.nr_ports = 1;
+
+    vser->vdev.get_features = get_features;
+    vser->vdev.get_config = get_config;
+    vser->vdev.set_config = set_config;
+
+    /*
+     * Register for the savevm section with the virtio-console name
+     * to preserve backward compat
+     */
+    register_savevm("virtio-console", -1, 2, virtio_serial_save,
+                    virtio_serial_load, vser);
+
+    return vdev;
+}
diff --git a/hw/virtio-serial.c b/hw/virtio-serial.c
new file mode 100644
index 0000000..1dc031e
--- /dev/null
+++ b/hw/virtio-serial.c
@@ -0,0 +1,111 @@
+/*
+ * Virtio Console and Generic Serial Port Devices
+ *
+ * Copyright Red Hat, Inc. 2009
+ *
+ * Authors:
+ *  Amit Shah <amit.shah@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "qemu-char.h"
+#include "virtio-serial.h"
+
+typedef struct VirtConsole {
+    VirtIOSerialPort port;
+    CharDriverState *chr;
+} VirtConsole;
+
+
+/* Callback function that's called when the guest sends us data */
+static size_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
+{
+    VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
+    ssize_t ret;
+
+    ret = qemu_chr_write(vcon->chr, buf, len);
+
+    return ret < 0 ? 0 : ret;
+}
+
+/* Readiness of the guest to accept data on a port */
+static int chr_can_read(void *opaque)
+{
+    VirtConsole *vcon = opaque;
+
+    return virtio_serial_guest_ready(&vcon->port);
+}
+
+/* Send data from a char device over to the guest */
+static void chr_read(void *opaque, const uint8_t *buf, int size)
+{
+    VirtConsole *vcon = opaque;
+
+    virtio_serial_write(&vcon->port, buf, size);
+}
+
+static void chr_event(void *opaque, int event)
+{
+    VirtConsole *vcon = opaque;
+
+    switch (event) {
+    case CHR_EVENT_OPENED: {
+        virtio_serial_open(&vcon->port);
+        break;
+    }
+    case CHR_EVENT_CLOSED:
+        virtio_serial_close(&vcon->port);
+        break;
+    }
+}
+
+/* Virtio Console Ports */
+static int virtconsole_initfn(VirtIOSerialDevice *dev)
+{
+    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);
+    VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
+
+    port->info = dev->info;
+
+    port->is_console = true;
+
+    if (vcon->chr) {
+        qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event,
+                              vcon);
+        port->info->have_data = flush_buf;
+    }
+    return 0;
+}
+
+static int virtconsole_exitfn(VirtIOSerialDevice *dev)
+{
+    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);
+    VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
+
+    if (vcon->chr) {
+        port->info->have_data = NULL;
+        qemu_chr_close(vcon->chr);
+    }
+
+    return 0;
+}
+
+static VirtIOSerialPortInfo virtconsole_info = {
+    .qdev.name     = "virtconsole",
+    .qdev.size     = sizeof(VirtConsole),
+    .init          = virtconsole_initfn,
+    .exit          = virtconsole_exitfn,
+    .qdev.props = (Property[]) {
+        DEFINE_PROP_UINT8("is_console", VirtConsole, port.is_console, 1),
+        DEFINE_PROP_CHR("chardev", VirtConsole, chr),
+        DEFINE_PROP_END_OF_LIST(),
+    },
+};
+
+static void virtconsole_register(void)
+{
+    virtio_serial_port_qdev_register(&virtconsole_info);
+}
+device_init(virtconsole_register)
diff --git a/hw/virtio-serial.h b/hw/virtio-serial.h
new file mode 100644
index 0000000..fe8e357
--- /dev/null
+++ b/hw/virtio-serial.h
@@ -0,0 +1,158 @@
+/*
+ * Virtio Serial / Console Support
+ *
+ * Copyright IBM, Corp. 2008
+ * Copyright Red Hat, Inc. 2009
+ *
+ * Authors:
+ *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
+ *  Amit Shah <amit.shah@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+#ifndef _QEMU_VIRTIO_SERIAL_H
+#define _QEMU_VIRTIO_SERIAL_H
+
+#include <stdbool.h>
+#include "qdev.h"
+#include "virtio.h"
+
+/* == Interface shared between the guest kernel and qemu == */
+
+/* The Virtio ID for virtio console / serial ports */
+#define VIRTIO_ID_CONSOLE		3
+
+/* Features supported */
+#define VIRTIO_CONSOLE_F_MULTIPORT	1
+
+struct virtio_console_config {
+    /*
+     * These two fields are used by VIRTIO_CONSOLE_F_SIZE which
+     * isn't implemented here yet
+     */
+    uint16_t cols;
+    uint16_t rows;
+
+    uint32_t max_nr_ports;
+    uint32_t nr_ports;
+} __attribute__((packed));
+
+struct virtio_console_control {
+    uint32_t id;		/* Port number */
+    uint16_t event;		/* The kind of control event (see below) */
+    uint16_t value;		/* Extra information for the key */
+};
+
+/* 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
+
+/* == In-qemu interface == */
+
+typedef struct VirtIOSerial VirtIOSerial;
+typedef struct VirtIOSerialBus VirtIOSerialBus;
+typedef struct VirtIOSerialPort VirtIOSerialPort;
+typedef struct VirtIOSerialPortInfo VirtIOSerialPortInfo;
+
+typedef struct VirtIOSerialDevice {
+    DeviceState qdev;
+    VirtIOSerialPortInfo *info;
+} VirtIOSerialDevice;
+
+/*
+ * This is the state that's shared between all the ports.  Some of the
+ * state is configurable via command-line options. Some of it can be
+ * set by individual devices in their initfn routines. Some of the
+ * state is set by the generic qdev device init routine.
+ */
+struct VirtIOSerialPort {
+    DeviceState dev;
+    VirtIOSerialPortInfo *info;
+
+    QTAILQ_ENTRY(VirtIOSerialPort) next;
+
+    /*
+     * This field gives us the virtio device as well as the qdev bus
+     * that we are associated with
+     */
+    VirtIOSerial *vser;
+
+    VirtQueue *ivq, *ovq;
+
+    /*
+     * This id helps identify ports between the guest and the host.
+     * The guest sends a "header" with this id with each data packet
+     * that it sends and the host can then find out which associated
+     * device to send out this data to
+     */
+    uint32_t id;
+
+    /* Identify if this is a port that binds with hvc in the guest */
+    uint8_t is_console;
+};
+
+struct VirtIOSerialPortInfo {
+    DeviceInfo qdev;
+    /*
+     * The per-port (or per-app) init function that's called when a
+     * new device is found on the bus.
+     */
+    int (*init)(VirtIOSerialDevice *dev);
+    /*
+     * Per-port exit function that's called when a port gets
+     * hot-unplugged or removed.
+     */
+    int (*exit)(VirtIOSerialDevice *dev);
+
+    /* Callbacks for guest events */
+        /* Guest opened device. */
+    void (*guest_open)(VirtIOSerialPort *port);
+        /* Guest closed device. */
+    void (*guest_close)(VirtIOSerialPort *port);
+
+        /* Guest is now ready to accept data (virtqueues set up). */
+    void (*guest_ready)(VirtIOSerialPort *port);
+
+    /*
+     * Guest wrote some data to the port. This data is handed over to
+     * the app via this callback. The app should return the number of
+     * bytes it successfully consumed.
+     */
+    size_t (*have_data)(VirtIOSerialPort *port, const uint8_t *buf, size_t len);
+};
+
+/* Interface to the virtio-serial bus */
+
+/*
+ * Individual ports/apps should call this function to register the port
+ * with the virtio-serial bus
+ */
+void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info);
+
+/*
+ * Open a connection to the port
+ *   Returns 0 on success (always).
+ */
+int virtio_serial_open(VirtIOSerialPort *port);
+
+/*
+ * Close the connection to the port
+ *   Returns 0 on success (always).
+ */
+int virtio_serial_close(VirtIOSerialPort *port);
+
+/*
+ * Send data to Guest
+ */
+ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
+                            size_t size);
+
+/*
+ * Query whether a guest is ready to receive data.
+ */
+size_t virtio_serial_guest_ready(VirtIOSerialPort *port);
+
+#endif
diff --git a/hw/virtio.h b/hw/virtio.h
index 7b2b327..62e882b 100644
--- a/hw/virtio.h
+++ b/hw/virtio.h
@@ -171,7 +171,7 @@ void virtio_bind_device(VirtIODevice *vdev, const VirtIOBindings *binding,
 /* Base devices.  */
 VirtIODevice *virtio_blk_init(DeviceState *dev, DriveInfo *dinfo);
 VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf);
-VirtIODevice *virtio_console_init(DeviceState *dev);
+VirtIODevice *virtio_serial_init(DeviceState *dev, uint32_t max_nr_ports);
 VirtIODevice *virtio_balloon_init(DeviceState *dev);
 
 void virtio_net_exit(VirtIODevice *vdev);
diff --git a/qemu-options.hx b/qemu-options.hx
index e2edd71..0c429e5 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1885,6 +1885,10 @@ DEF("virtioconsole", HAS_ARG, QEMU_OPTION_virtiocon, \
 STEXI
 @item -virtioconsole @var{c}
 Set virtio console.
+
+This option is maintained for backward compatibility.
+
+Please use @code{-device virtconsole} for the new way of invocation.
 ETEXI
 
 DEF("show-cursor", 0, QEMU_OPTION_show_cursor, \
diff --git a/sysemu.h b/sysemu.h
index 9d80bb2..9c3b281 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -231,12 +231,6 @@ extern CharDriverState *serial_hds[MAX_SERIAL_PORTS];
 
 extern CharDriverState *parallel_hds[MAX_PARALLEL_PORTS];
 
-/* virtio consoles */
-
-#define MAX_VIRTIO_CONSOLES 1
-
-extern CharDriverState *virtcon_hds[MAX_VIRTIO_CONSOLES];
-
 #define TFR(expr) do { if ((expr) != -1) break; } while (errno == EINTR)
 
 #ifdef HAS_AUDIO
diff --git a/vl.c b/vl.c
index 06cb40d..89663a4 100644
--- a/vl.c
+++ b/vl.c
@@ -173,6 +173,8 @@ int main(int argc, char **argv)
 
 #define DEFAULT_RAM_SIZE 128
 
+#define MAX_VIRTIO_CONSOLES 1
+
 static const char *data_dir;
 const char *bios_name = NULL;
 /* Note: drives_table[MAX_DRIVES] is a dummy block driver if none available
-- 
1.6.2.5

[Qemu-devel] [PATCH 3/8] virtio-serial-bus: Maintain guest and host port open/close state

[Amit Shah]

Via control channel messages, the guest can tell us whether a port got
opened or closed. Similarly, we can also indicate to the guest of host
port open/close events.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-serial-bus.c |   94 ++++++++++++++++++++++++++++++++++++++++++++++++
 hw/virtio-serial.h     |    6 +++
 2 files changed, 100 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index e8bbd7d..5bf2990 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -66,6 +66,11 @@ static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)
     return NULL;
 }
 
+static bool use_multiport(VirtIOSerial *vser)
+{
+    return vser->vdev.guest_features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
+}
+
 static size_t write_to_port(VirtIOSerialPort *port,
                             const uint8_t *buf, size_t size)
 {
@@ -139,11 +144,22 @@ static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,
 /* Functions for use inside qemu to open and read from/write to ports */
 int virtio_serial_open(VirtIOSerialPort *port)
 {
+    /* Don't allow opening an already-open port */
+    if (port->host_connected) {
+        return 0;
+    }
+    /* Send port open notification to the guest */
+    port->host_connected = true;
+    send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
+
     return 0;
 }
 
 int virtio_serial_close(VirtIOSerialPort *port)
 {
+    port->host_connected = false;
+    send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
+
     return 0;
 }
 
@@ -151,6 +167,9 @@ int virtio_serial_close(VirtIOSerialPort *port)
 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
                             size_t size)
 {
+    if (!port || !port->host_connected || !port->guest_connected) {
+        return 0;
+    }
     return write_to_port(port, buf, size);
 }
 
@@ -167,6 +186,9 @@ size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
         virtio_queue_empty(vq)) {
         return 0;
     }
+    if (use_multiport(port->vser) && !port->guest_connected) {
+        return 0;
+    }
 
     if (virtqueue_avail_bytes(vq, 4096, 0)) {
         return 4096;
@@ -203,6 +225,11 @@ static void handle_control_message(VirtIOSerial *vser, void *buf)
         if (port->is_console) {
             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
         }
+
+        if (port->host_connected) {
+            send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
+        }
+
         /*
          * When the guest has asked us for this information it means
          * the guest is all setup and has its virtqueues
@@ -213,6 +240,19 @@ static void handle_control_message(VirtIOSerial *vser, void *buf)
             port->info->guest_ready(port);
         }
         break;
+
+    case VIRTIO_CONSOLE_PORT_OPEN:
+        port->guest_connected = cpkt.value;
+        if (cpkt.value && port->info->guest_open) {
+            /* Send the guest opened notification if an app is interested */
+            port->info->guest_open(port);
+        }
+
+        if (!cpkt.value && port->info->guest_close) {
+            /* Send the guest closed notification if an app is interested */
+            port->info->guest_close(port);
+        }
+        break;
     }
 }
 
@@ -302,6 +342,8 @@ static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
 static void virtio_serial_save(QEMUFile *f, void *opaque)
 {
     VirtIOSerial *s = opaque;
+    VirtIOSerialPort *port;
+    uint32_t nr_active_ports;
 
     /* The virtio device */
     virtio_save(&s->vdev, f);
@@ -310,15 +352,41 @@ static void virtio_serial_save(QEMUFile *f, void *opaque)
     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 */
+
+    /* Do this because we might have hot-unplugged some ports */
+    nr_active_ports = 0;
+    QTAILQ_FOREACH(port, &s->ports, next)
+        nr_active_ports++;
+
+    qemu_put_be32s(f, &nr_active_ports);
+
+    /*
+     * 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);
+    }
 }
 
 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
 {
     VirtIOSerial *s = opaque;
+    VirtIOSerialPort *port;
+    uint32_t nr_active_ports;
+    unsigned int i;
 
     if (version_id > 2) {
         return -EINVAL;
     }
+
     /* The virtio device */
     virtio_load(&s->vdev, f);
 
@@ -331,6 +399,20 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
     qemu_get_be16s(f, &s->config.rows);
     s->config.nr_ports = qemu_get_be32(f);
 
+    /* Items in struct VirtIOSerial */
+
+    qemu_get_be32s(f, &nr_active_ports);
+
+    /* Items in struct VirtIOSerialPort */
+    for (i = 0; i < nr_active_ports; i++) {
+        uint32_t id;
+
+        id = qemu_get_be32(f);
+        port = find_port_by_id(s, id);
+
+        port->guest_connected = qemu_get_byte(f);
+    }
+
     return 0;
 }
 
@@ -360,6 +442,10 @@ static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)
 
     monitor_printf(mon, "%*s dev-prop-int: id: %u\n",
                    indent, "", port->id);
+    monitor_printf(mon, "%*s dev-prop-int: guest_connected: %d\n",
+                   indent, "", port->guest_connected);
+    monitor_printf(mon, "%*s dev-prop-int: host_connected: %d\n",
+                   indent, "", port->host_connected);
 }
 
 static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
@@ -393,6 +479,14 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
 
     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
+         * knowing if a guest port is connected.
+         */
+        port->guest_connected = true;
+    }
+
     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);
     port->ivq = port->vser->ivqs[port->id];
     port->ovq = port->vser->ovqs[port->id];
diff --git a/hw/virtio-serial.h b/hw/virtio-serial.h
index fe8e357..d9c7acb 100644
--- a/hw/virtio-serial.h
+++ b/hw/virtio-serial.h
@@ -49,6 +49,7 @@ struct virtio_console_control {
 #define VIRTIO_CONSOLE_PORT_READY	0
 #define VIRTIO_CONSOLE_CONSOLE_PORT	1
 #define VIRTIO_CONSOLE_RESIZE		2
+#define VIRTIO_CONSOLE_PORT_OPEN	3
 
 /* == In-qemu interface == */
 
@@ -92,6 +93,11 @@ struct VirtIOSerialPort {
 
     /* Identify if this is a port that binds with hvc in the guest */
     uint8_t is_console;
+
+    /* Is the corresponding guest device open? */
+    bool guest_connected;
+    /* Is this device open for IO on the host? */
+    bool host_connected;
 };
 
 struct VirtIOSerialPortInfo {
-- 
1.6.2.5

[Qemu-devel] [PATCH 4/8] virtio-serial-bus: Add a port 'name' property for port discovery in guests

[Amit Shah]

The port 'id' or number is internal state between the guest kernel and
our bus implementation. This is invocation-dependent and isn't part of
the guest-host ABI.

To correcly enumerate and map ports between the host and the guest, the
'name' property is used.

Example:

    -device virtserialport,name=org.qemu.port.0

This invocation will get us a char device in the guest at:

    /dev/virtio-ports/org.qemu.port.0

which can be a symlink to

    /dev/vport0p3

This 'name' property is exposed by the guest kernel in a sysfs
attribute:

    /sys/kernel/virtio-ports/vport0p3/name

A simple udev script can pick up this name and create the symlink
mentioned above.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-serial-bus.c |   17 +++++++++++++++++
 hw/virtio-serial.c     |    1 +
 hw/virtio-serial.h     |    8 ++++++++
 3 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index 5bf2990..7e100d0 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -204,6 +204,8 @@ static void handle_control_message(VirtIOSerial *vser, void *buf)
 {
     struct VirtIOSerialPort *port;
     struct virtio_console_control cpkt, *gcpkt;
+    uint8_t *buffer;
+    size_t buffer_len;
 
     gcpkt = buf;
     port = find_port_by_id(vser, ldl_p(&gcpkt->id));
@@ -226,6 +228,21 @@ static void handle_control_message(VirtIOSerial *vser, void *buf)
             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);
         }
 
+        if (port->name) {
+            stw_p(&cpkt.event, VIRTIO_CONSOLE_PORT_NAME);
+            stw_p(&cpkt.value, 1);
+
+            buffer_len = sizeof(cpkt) + strlen(port->name) + 1;
+            buffer = qemu_malloc(buffer_len);
+
+            memcpy(buffer, &cpkt, sizeof(cpkt));
+            memcpy(buffer + sizeof(cpkt), port->name, strlen(port->name));
+            buffer[buffer_len - 1] = 0;
+
+            send_control_msg(port, buffer, buffer_len);
+            qemu_free(buffer);
+        }
+
         if (port->host_connected) {
             send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
         }
diff --git a/hw/virtio-serial.c b/hw/virtio-serial.c
index 1dc031e..9c2c93c 100644
--- a/hw/virtio-serial.c
+++ b/hw/virtio-serial.c
@@ -100,6 +100,7 @@ static VirtIOSerialPortInfo virtconsole_info = {
     .qdev.props = (Property[]) {
         DEFINE_PROP_UINT8("is_console", VirtConsole, port.is_console, 1),
         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
+        DEFINE_PROP_STRING("name", VirtConsole, port.name),
         DEFINE_PROP_END_OF_LIST(),
     },
 };
diff --git a/hw/virtio-serial.h b/hw/virtio-serial.h
index d9c7acb..28ea7da 100644
--- a/hw/virtio-serial.h
+++ b/hw/virtio-serial.h
@@ -50,6 +50,7 @@ struct virtio_console_control {
 #define VIRTIO_CONSOLE_CONSOLE_PORT	1
 #define VIRTIO_CONSOLE_RESIZE		2
 #define VIRTIO_CONSOLE_PORT_OPEN	3
+#define VIRTIO_CONSOLE_PORT_NAME	4
 
 /* == In-qemu interface == */
 
@@ -84,6 +85,13 @@ struct VirtIOSerialPort {
     VirtQueue *ivq, *ovq;
 
     /*
+     * This name is sent to the guest and exported via sysfs.
+     * The guest could create symlinks based on this information.
+     * The name is in the reverse fqdn format, like org.qemu.console.0
+     */
+    char *name;
+
+    /*
      * This id helps identify ports between the guest and the host.
      * The guest sends a "header" with this id with each data packet
      * that it sends and the host can then find out which associated
-- 
1.6.2.5

[Qemu-devel] [PATCH 5/8] virtio-serial-bus: Add ability to hot-unplug ports

[Amit Shah]

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-serial-bus.c |    2 ++
 hw/virtio-serial.h     |    1 +
 2 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index 7e100d0..403268f 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -520,6 +520,8 @@ 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);
+
     /*
      * Don't decrement nr_ports here; thus we keep a linearly
      * increasing port id. Not utilising an id again saves us a couple
diff --git a/hw/virtio-serial.h b/hw/virtio-serial.h
index 28ea7da..f297b00 100644
--- a/hw/virtio-serial.h
+++ b/hw/virtio-serial.h
@@ -51,6 +51,7 @@ struct virtio_console_control {
 #define VIRTIO_CONSOLE_RESIZE		2
 #define VIRTIO_CONSOLE_PORT_OPEN	3
 #define VIRTIO_CONSOLE_PORT_NAME	4
+#define VIRTIO_CONSOLE_PORT_REMOVE	5
 
 /* == In-qemu interface == */
 
-- 
1.6.2.5

[Qemu-devel] [PATCH 6/8] virtio-serial: Add a 'virtserialport' device for generic serial port support

[Amit Shah]

This commit adds a simple chardev-based serial port. Any data the guest
sends is forwarded to the chardev and vice-versa.

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.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-serial.c |   34 ++++++++++++++++++++++++++++++++++
 1 files changed, 34 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-serial.c b/hw/virtio-serial.c
index 9c2c93c..bd44ec6 100644
--- a/hw/virtio-serial.c
+++ b/hw/virtio-serial.c
@@ -110,3 +110,37 @@ static void virtconsole_register(void)
     virtio_serial_port_qdev_register(&virtconsole_info);
 }
 device_init(virtconsole_register)
+
+/* Generic Virtio Serial Ports */
+static int virtserialport_initfn(VirtIOSerialDevice *dev)
+{
+    VirtIOSerialPort *port = DO_UPCAST(VirtIOSerialPort, dev, &dev->qdev);
+    VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
+
+    port->info = dev->info;
+
+    if (vcon->chr) {
+        qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event,
+                              vcon);
+        port->info->have_data = flush_buf;
+    }
+    return 0;
+}
+
+static VirtIOSerialPortInfo virtserialport_info = {
+    .qdev.name     = "virtserialport",
+    .qdev.size     = sizeof(VirtConsole),
+    .init          = virtserialport_initfn,
+    .exit          = virtconsole_exitfn,
+    .qdev.props = (Property[]) {
+        DEFINE_PROP_CHR("chardev", VirtConsole, chr),
+        DEFINE_PROP_STRING("name", VirtConsole, port.name),
+        DEFINE_PROP_END_OF_LIST(),
+    },
+};
+
+static void virtserialport_register(void)
+{
+    virtio_serial_port_qdev_register(&virtserialport_info);
+}
+device_init(virtserialport_register)
-- 
1.6.2.5

[Qemu-devel] [PATCH 7/8] Move virtio-serial to Makefile.objs

[Amit Shah]

There's nothing target-dependent in the virtio-serial code so allow it
to be compiled just once for all the targets.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 Makefile.objs   |    2 +-
 Makefile.target |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Makefile.objs b/Makefile.objs
index 5802d39..77ff7f6 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -127,7 +127,7 @@ user-obj-y += cutils.o cache-utils.o
 
 hw-obj-y =
 hw-obj-y += loader.o
-hw-obj-y += virtio.o
+hw-obj-y += virtio.o virtio-serial.o
 hw-obj-y += fw_cfg.o
 hw-obj-y += watchdog.o
 hw-obj-$(CONFIG_ECC) += ecc.o
diff --git a/Makefile.target b/Makefile.target
index 60df16d..0bf2253 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -172,7 +172,7 @@ ifdef CONFIG_SOFTMMU
 obj-y = vl.o async.o monitor.o pci.o pci_host.o pcie_host.o machine.o gdbstub.o
 # virtio has to be here due to weird dependency between PCI and virtio-net.
 # need to fix this properly
-obj-y += virtio-blk.o virtio-balloon.o virtio-net.o virtio-serial.o virtio-serial-bus.o virtio-pci.o
+obj-y += virtio-blk.o virtio-balloon.o virtio-net.o virtio-pci.o virtio-serial-bus.o
 obj-$(CONFIG_KVM) += kvm.o kvm-all.o
 obj-$(CONFIG_ISA_MMIO) += isa_mmio.o
 LIBS+=-lz
-- 
1.6.2.5

[Qemu-devel] [PATCH 8/8] virtio-serial: Use MSI vectors for port virtqueues

[Amit Shah]

This commit enables the use of MSI interrupts for virtqueue
notifications for ports. We use nr_ports + 1 (for control channel) msi
entries for the ports, as only the in_vq operations need an interrupt on
the guest.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-pci.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index e7fabfb..709d13e 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -499,10 +499,13 @@ static int virtio_serial_init_pci(PCIDevice *pci_dev)
     if (!vdev) {
         return -1;
     }
+    vdev->nvectors = proxy->nvectors ? proxy->nvectors
+                                     : proxy->max_virtserial_ports + 1;
     virtio_init_pci(proxy, vdev,
                     PCI_VENDOR_ID_REDHAT_QUMRANET,
                     PCI_DEVICE_ID_VIRTIO_CONSOLE,
                     proxy->class_code, 0x00);
+    proxy->nvectors = vdev->nvectors;
     return 0;
 }
 
@@ -581,6 +584,7 @@ static PCIDeviceInfo virtio_info[] = {
         .init      = virtio_serial_init_pci,
         .exit      = virtio_exit_pci,
         .qdev.props = (Property[]) {
+            DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 0),
             DEFINE_PROP_HEX32("class", VirtIOPCIProxy, class_code, 0),
             DEFINE_VIRTIO_COMMON_FEATURES(VirtIOPCIProxy, host_features),
             DEFINE_PROP_UINT32("max_ports", VirtIOPCIProxy, max_virtserial_ports,
-- 
1.6.2.5

Re: [Qemu-devel] [PATCH 1/8] virtio: Remove duplicate macro definition for max. virtqueues, bump up the max

[Anthony Liguori]

On 01/19/2010 01:06 PM, Amit Shah wrote:
> VIRTIO_PCI_QUEUE_MAX is redefined in hw/virtio.c. Let's just keep it in
> hw/virtio.h.
>
> Also, bump up the value of the maximum allowed virtqueues to 64. This is
> in preparation to allow multiple ports per virtio-console device.
>
> Signed-off-by: Amit Shah<amit.shah@redhat.com>
>    

Applied.  Thanks.

Regards,

Anthony Liguori
> ---
>   hw/virtio.c |    2 --
>   hw/virtio.h |    2 +-
>   2 files changed, 1 insertions(+), 3 deletions(-)
>
> diff --git a/hw/virtio.c b/hw/virtio.c
> index fa7184a..7c020a3 100644
> --- a/hw/virtio.c
> +++ b/hw/virtio.c
> @@ -75,8 +75,6 @@ struct VirtQueue
>       void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq);
>   };
>
> -#define VIRTIO_PCI_QUEUE_MAX        16
> -
>   /* virt queue functions */
>   static void virtqueue_init(VirtQueue *vq)
>   {
> diff --git a/hw/virtio.h b/hw/virtio.h
> index 3994cc9..7b2b327 100644
> --- a/hw/virtio.h
> +++ b/hw/virtio.h
> @@ -90,7 +90,7 @@ typedef struct {
>       unsigned (*get_features)(void * opaque);
>   } VirtIOBindings;
>
> -#define VIRTIO_PCI_QUEUE_MAX 16
> +#define VIRTIO_PCI_QUEUE_MAX 64
>
>   #define VIRTIO_NO_VECTOR 0xffff
>
>    

Re: [Qemu-devel] [PATCH 1/8] virtio: Remove duplicate macro definition for max. virtqueues, bump up the max

[Markus Armbruster]

Amit, what about renaming hw/virtio-serial.c to a less misleading name
now?

Re: [Qemu-devel] [PATCH 1/8] virtio: Remove duplicate macro definition for max. virtqueues, bump up the max

[Amit Shah]

On (Thu) Jan 21 2010 [10:53:36], Markus Armbruster wrote:
> Amit, what about renaming hw/virtio-serial.c to a less misleading name
> now?

I'm going to push that upstream; Anthony in the past indicated he was ok
with it.

		Amit