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[PATCH v2 15/16] hw/char/virtio-serial: Do not expose the 'emergency-write' property

Philippe Mathieu-Daudé posted 16 patches 6 months, 2 weeks ago
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[PATCH v2 15/16] hw/char/virtio-serial: Do not expose the 'emergency-write' property
Posted by Philippe Mathieu-Daudé 6 months, 2 weeks ago 
The VIRTIO_CONSOLE_F_EMERG_WRITE feature bit was only set
in the hw_compat_2_7[] array, via the 'emergency-write=off'
property. We removed all machines using that array, lets remove
that property. All instances have this feature bit set and
it can not be disabled.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/char/virtio-serial-bus.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index eb79f5258b6..31bd1b7535d 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -1019,6 +1019,13 @@ static void virtser_port_device_unrealize(DeviceState *dev)
     }
 }
 
+static void virtio_serial_instance_init(Object *obj)
+{
+    VirtIOSerial *vser = VIRTIO_SERIAL(obj);
+
+    vser->host_features |= BIT_ULL(VIRTIO_CONSOLE_F_EMERG_WRITE);
+}
+
 static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
@@ -1155,8 +1162,6 @@ static const VMStateDescription vmstate_virtio_console = {
 static const Property virtio_serial_properties[] = {
     DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
                                                   31),
-    DEFINE_PROP_BIT64("emergency-write", VirtIOSerial, host_features,
-                      VIRTIO_CONSOLE_F_EMERG_WRITE, true),
 };
 
 static void virtio_serial_class_init(ObjectClass *klass, const void *data)
@@ -1186,6 +1191,7 @@ static void virtio_serial_class_init(ObjectClass *klass, const void *data)
 static const TypeInfo virtio_device_info = {
     .name = TYPE_VIRTIO_SERIAL,
     .parent = TYPE_VIRTIO_DEVICE,
+    .instance_init = virtio_serial_instance_init,
     .instance_size = sizeof(VirtIOSerial),
     .class_init = virtio_serial_class_init,
     .interfaces = (const InterfaceInfo[]) {
-- 
2.47.1
Re: [PATCH v2 15/16] hw/char/virtio-serial: Do not expose the 'emergency-write' property
Posted by Mark Cave-Ayland 6 months, 2 weeks ago 
On 01/05/2025 19:36, Philippe Mathieu-Daudé wrote:

> The VIRTIO_CONSOLE_F_EMERG_WRITE feature bit was only set
> in the hw_compat_2_7[] array, via the 'emergency-write=off'
> property. We removed all machines using that array, lets remove
> that property. All instances have this feature bit set and
> it can not be disabled.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>   hw/char/virtio-serial-bus.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
> index eb79f5258b6..31bd1b7535d 100644
> --- a/hw/char/virtio-serial-bus.c
> +++ b/hw/char/virtio-serial-bus.c
> @@ -1019,6 +1019,13 @@ static void virtser_port_device_unrealize(DeviceState *dev)
>       }
>   }
>   
> +static void virtio_serial_instance_init(Object *obj)
> +{
> +    VirtIOSerial *vser = VIRTIO_SERIAL(obj);
> +
> +    vser->host_features |= BIT_ULL(VIRTIO_CONSOLE_F_EMERG_WRITE);
> +}
> +
>   static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
>   {
>       VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> @@ -1155,8 +1162,6 @@ static const VMStateDescription vmstate_virtio_console = {
>   static const Property virtio_serial_properties[] = {
>       DEFINE_PROP_UINT32("max_ports", VirtIOSerial, serial.max_virtserial_ports,
>                                                     31),
> -    DEFINE_PROP_BIT64("emergency-write", VirtIOSerial, host_features,
> -                      VIRTIO_CONSOLE_F_EMERG_WRITE, true),
>   };
>   
>   static void virtio_serial_class_init(ObjectClass *klass, const void *data)
> @@ -1186,6 +1191,7 @@ static void virtio_serial_class_init(ObjectClass *klass, const void *data)
>   static const TypeInfo virtio_device_info = {
>       .name = TYPE_VIRTIO_SERIAL,
>       .parent = TYPE_VIRTIO_DEVICE,
> +    .instance_init = virtio_serial_instance_init,
>       .instance_size = sizeof(VirtIOSerial),
>       .class_init = virtio_serial_class_init,
>       .interfaces = (const InterfaceInfo[]) {

You could also consider removing vser->host_features completely, since 
it is always ORd into the host_features list in get_features(), plus all 
remaining mentions are of the form:

if (virtio_has_feature(vser->host_features,
         VIRTIO_CONSOLE_F_EMERG_WRITE)) { ... }


ATB,

Mark.
Re: [PATCH v2 15/16] hw/char/virtio-serial: Do not expose the 'emergency-write' property
Posted by Philippe Mathieu-Daudé 6 months, 2 weeks ago 
On 2/5/25 11:41, Mark Cave-Ayland wrote:
> On 01/05/2025 19:36, Philippe Mathieu-Daudé wrote:
> 
>> The VIRTIO_CONSOLE_F_EMERG_WRITE feature bit was only set
>> in the hw_compat_2_7[] array, via the 'emergency-write=off'
>> property. We removed all machines using that array, lets remove
>> that property. All instances have this feature bit set and
>> it can not be disabled.
>>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> ---
>>   hw/char/virtio-serial-bus.c | 10 ++++++++--
>>   1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
>> index eb79f5258b6..31bd1b7535d 100644
>> --- a/hw/char/virtio-serial-bus.c
>> +++ b/hw/char/virtio-serial-bus.c
>> @@ -1019,6 +1019,13 @@ static void 
>> virtser_port_device_unrealize(DeviceState *dev)
>>       }
>>   }
>> +static void virtio_serial_instance_init(Object *obj)
>> +{
>> +    VirtIOSerial *vser = VIRTIO_SERIAL(obj);
>> +
>> +    vser->host_features |= BIT_ULL(VIRTIO_CONSOLE_F_EMERG_WRITE);
>> +}
>> +
>>   static void virtio_serial_device_realize(DeviceState *dev, Error 
>> **errp)
>>   {
>>       VirtIODevice *vdev = VIRTIO_DEVICE(dev);
>> @@ -1155,8 +1162,6 @@ static const VMStateDescription 
>> vmstate_virtio_console = {
>>   static const Property virtio_serial_properties[] = {
>>       DEFINE_PROP_UINT32("max_ports", VirtIOSerial, 
>> serial.max_virtserial_ports,
>>                                                     31),
>> -    DEFINE_PROP_BIT64("emergency-write", VirtIOSerial, host_features,
>> -                      VIRTIO_CONSOLE_F_EMERG_WRITE, true),
>>   };
>>   static void virtio_serial_class_init(ObjectClass *klass, const void 
>> *data)
>> @@ -1186,6 +1191,7 @@ static void virtio_serial_class_init(ObjectClass 
>> *klass, const void *data)
>>   static const TypeInfo virtio_device_info = {
>>       .name = TYPE_VIRTIO_SERIAL,
>>       .parent = TYPE_VIRTIO_DEVICE,
>> +    .instance_init = virtio_serial_instance_init,
>>       .instance_size = sizeof(VirtIOSerial),
>>       .class_init = virtio_serial_class_init,
>>       .interfaces = (const InterfaceInfo[]) {
> 
> You could also consider removing vser->host_features completely, since 
> it is always ORd into the host_features list in get_features(), plus all 
> remaining mentions are of the form:
> 
> if (virtio_has_feature(vser->host_features,
>          VIRTIO_CONSOLE_F_EMERG_WRITE)) { ... }

Good remark, thanks!

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