[Qemu-devel] [PATCH 1/3] virtio-console: Check if chardev backends available before calling into them

[Qemu-devel] [PATCH 1/3] virtio-console: Check if chardev backends available before calling into them

[Amit Shah]

For the callback functions invoked by the virtio-serial-bus code, check
if we have chardev backends registered before we call into the chardev
functions.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-console.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-console.c b/hw/virtio-console.c
index d3351c8..dbbea76 100644
--- a/hw/virtio-console.c
+++ b/hw/virtio-console.c
@@ -27,6 +27,11 @@ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
     ssize_t ret;
 
+    if (!vcon->chr) {
+        /* If there's no backend, we can just say we consumed all data. */
+        return len;
+    }
+
     ret = qemu_chr_fe_write(vcon->chr, buf, len);
     trace_virtio_console_flush_buf(port->id, len, ret);
 
@@ -52,6 +57,9 @@ static void guest_open(VirtIOSerialPort *port)
 {
     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
 
+    if (!vcon->chr) {
+        return;
+    }
     qemu_chr_fe_open(vcon->chr);
 }
 
@@ -60,6 +68,9 @@ static void guest_close(VirtIOSerialPort *port)
 {
     VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
 
+    if (!vcon->chr) {
+        return;
+    }
     qemu_chr_fe_close(vcon->chr);
 }
 
-- 
1.7.7.4

[Qemu-devel] [PATCH 2/3] virtio-console: Properly initialise class methods

[Amit Shah]

The earlier code really was a hack: initialising class methods in an
object init function as noted by Anthony.

The motivation for that was to not have the virtio-serial-bus call into
the callback functions if there was no chardev backend registered.
However, that really wasn't a worthwhile optimisation, and definitely
not one that was well-implemented.  Get rid of it.

Reported-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-console.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/virtio-console.c b/hw/virtio-console.c
index dbbea76..73d866a 100644
--- a/hw/virtio-console.c
+++ b/hw/virtio-console.c
@@ -120,9 +120,6 @@ static int virtconsole_initfn(VirtIOSerialPort *port)
     if (vcon->chr) {
         qemu_chr_add_handlers(vcon->chr, chr_can_read, chr_read, chr_event,
                               vcon);
-        info->have_data = flush_buf;
-        info->guest_open = guest_open;
-        info->guest_close = guest_close;
     }
 
     return 0;
@@ -149,6 +146,9 @@ static VirtIOSerialPortInfo virtconsole_info = {
     .is_console    = true,
     .init          = virtconsole_initfn,
     .exit          = virtconsole_exitfn,
+    .have_data     = flush_buf,
+    .guest_open    = guest_open,
+    .guest_close   = guest_close,
     .qdev.props = (Property[]) {
         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
         DEFINE_PROP_END_OF_LIST(),
@@ -166,6 +166,9 @@ static VirtIOSerialPortInfo virtserialport_info = {
     .qdev.size     = sizeof(VirtConsole),
     .init          = virtconsole_initfn,
     .exit          = virtconsole_exitfn,
+    .have_data     = flush_buf,
+    .guest_open    = guest_open,
+    .guest_close   = guest_close,
     .qdev.props = (Property[]) {
         DEFINE_PROP_CHR("chardev", VirtConsole, chr),
         DEFINE_PROP_END_OF_LIST(),
-- 
1.7.7.4

[Qemu-devel] [PATCH 3/3] virtio-serial-bus: Ports are expected to implement 'have_data' callback

[Amit Shah]

There's no need to check if ports can accept any incoming data from the
guest each time the guest sends data.  Check if the port implements such
functionality during port initialisation.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-serial-bus.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index a4825b9..fe0233f 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -466,13 +466,11 @@ static void handle_output(VirtIODevice *vdev, VirtQueue *vq)
 {
     VirtIOSerial *vser;
     VirtIOSerialPort *port;
-    VirtIOSerialPortInfo *info;
 
     vser = DO_UPCAST(VirtIOSerial, vdev, vdev);
     port = find_port_by_vq(vser, vq);
-    info = port ? DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info) : NULL;
 
-    if (!port || !port->host_connected || !info->have_data) {
+    if (!port || !port->host_connected) {
         discard_vq_data(vq, vdev);
         return;
     }
@@ -746,6 +744,8 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)
     port->vser = bus->vser;
     port->bh = qemu_bh_new(flush_queued_data_bh, port);
 
+    assert(info->have_data);
+
     /*
      * Is the first console port we're seeing? If so, put it up at
      * location 0. This is done for backward compatibility (old
-- 
1.7.7.4

Re: [Qemu-devel] [PATCH 1/3] virtio-console: Check if chardev backends available before calling into them

[Anthony Liguori]

On 12/21/2011 12:58 AM, Amit Shah wrote:
> For the callback functions invoked by the virtio-serial-bus code, check
> if we have chardev backends registered before we call into the chardev
> functions.
>
> Signed-off-by: Amit Shah<amit.shah@redhat.com>

Applied all.  Thanks.

Regards,

Anthony Liguori

> ---
>   hw/virtio-console.c |   11 +++++++++++
>   1 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/hw/virtio-console.c b/hw/virtio-console.c
> index d3351c8..dbbea76 100644
> --- a/hw/virtio-console.c
> +++ b/hw/virtio-console.c
> @@ -27,6 +27,11 @@ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len)
>       VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
>       ssize_t ret;
>
> +    if (!vcon->chr) {
> +        /* If there's no backend, we can just say we consumed all data. */
> +        return len;
> +    }
> +
>       ret = qemu_chr_fe_write(vcon->chr, buf, len);
>       trace_virtio_console_flush_buf(port->id, len, ret);
>
> @@ -52,6 +57,9 @@ static void guest_open(VirtIOSerialPort *port)
>   {
>       VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
>
> +    if (!vcon->chr) {
> +        return;
> +    }
>       qemu_chr_fe_open(vcon->chr);
>   }
>
> @@ -60,6 +68,9 @@ static void guest_close(VirtIOSerialPort *port)
>   {
>       VirtConsole *vcon = DO_UPCAST(VirtConsole, port, port);
>
> +    if (!vcon->chr) {
> +        return;
> +    }
>       qemu_chr_fe_close(vcon->chr);
>   }
>