Re: [PATCH 1/2] drm/drm_ras: Add drm_ras netlink error event

["Tauro, Riana" <riana.tauro@intel.com>]

On 6/1/2026 11:52 AM, Raag Jadav wrote:
> On Mon, May 18, 2026 at 04:50:50PM +0530, Riana Tauro wrote:
>> Define a new netlink event 'error-event' and a new multicast group
>> 'error-notify' in drm_ras. Each event contains device name, node and
>> error information to identify the error triggering the event.
>>
>> Add drm_ras_nl_error_event() to trigger an event from the driver.
>> Userspace must subscribe to 'error-notify' to receive 'error-event'
>> notifications.
>>
>> Usage:
>>
>>      $ sudo ./tools/net/ynl/pyynl/cli.py --family drm_ras \
> Nit: Make the leading space consistent with other patches.
>
>>        --subscribe error-notify
>>
>> Cc: Jakub Kicinski <kuba@kernel.org>
>> Cc: Zack McKevitt <zachary.mckevitt@oss.qualcomm.com>
>> Cc: Lijo Lazar <lijo.lazar@amd.com>
>> Cc: Hawking Zhang <Hawking.Zhang@amd.com>
>> Cc: David S. Miller <davem@davemloft.net>
>> Cc: Paolo Abeni <pabeni@redhat.com>
>> Cc: Eric Dumazet <edumazet@google.com>
>> Signed-off-by: Riana Tauro <riana.tauro@intel.com>
>> ---
>>   Documentation/gpu/drm-ras.rst            | 21 ++++++
>>   Documentation/netlink/specs/drm_ras.yaml | 50 ++++++++++++++
>>   drivers/gpu/drm/drm_ras.c                | 86 ++++++++++++++++++++++++
>>   drivers/gpu/drm/drm_ras_nl.c             |  6 ++
>>   drivers/gpu/drm/drm_ras_nl.h             |  4 ++
>>   include/drm/drm_ras.h                    |  5 ++
>>   include/uapi/drm/drm_ras.h               | 15 +++++
>>   7 files changed, 187 insertions(+)
>>
>> diff --git a/Documentation/gpu/drm-ras.rst b/Documentation/gpu/drm-ras.rst
>> index 83c21853b74b..5a96dde75539 100644
>> --- a/Documentation/gpu/drm-ras.rst
>> +++ b/Documentation/gpu/drm-ras.rst
>> @@ -56,6 +56,7 @@ User space tools can:
>>     ``node-id`` and ``error-id`` as parameters.
>>   * Clear specific error counters with the ``clear-error-counter`` command, using both
>>     ``node-id`` and ``error-id`` as parameters.
>> +* Subscribe to the ``error-notify`` multicast group to receive ``error-event`` notifications.
>>   
>>   YAML-based Interface
>>   --------------------
>> @@ -111,3 +112,23 @@ Example: Clear an error counter for a given node
>>   
>>       sudo ynl --family drm_ras --do clear-error-counter --json '{"node-id":0, "error-id":1}'
>>       None
>> +
>> +Example: Subscribe to ``error-notify`` multicast group
>> +
>> +.. code-block:: bash
>> +
>> +    sudo ./tools/net/ynl/pyynl/cli.py --family drm_ras --output-json --subscribe error-notify
> So ynl can't do this? If yes, make it consistent with other commands
> (and also in commit message). If no, please document it.

Sorry . My mistake. Was using ubuntu and copy pasted directly from 
command line.
Should work with ynl. Will check and update it

>
>> +
>> +.. code-block:: json
>> +
>> +    {
>> +        "name": "error-event",
>> +        "msg": {
>> +            "device-name": "0000:03:00.0",
>> +            "node-id": 1,
>> +            "node-name": "uncorrectable-errors",
>> +            "error-id": 1,
>> +            "error-name": "error_name1",
>> +            "error-value": 1
>> +        }
>> +    }
>> diff --git a/Documentation/netlink/specs/drm_ras.yaml b/Documentation/netlink/specs/drm_ras.yaml
>> index e113056f8c01..d94c73a61aea 100644
>> --- a/Documentation/netlink/specs/drm_ras.yaml
>> +++ b/Documentation/netlink/specs/drm_ras.yaml
>> @@ -69,6 +69,35 @@ attribute-sets:
>>           name: error-value
>>           type: u32
>>           doc: Current value of the requested error counter.
>> +  -
>> +    name: error-event-attrs
>> +    attributes:
>> +      -
>> +        name: device-name
>> +        type: string
>> +        doc: >-
>> +             Device name chosen by the driver at registration.
>> +             Can be a PCI BDF, UUID, or module name if unique.
>> +      -
>> +        name: node-id
> Curious, can we reuse existing partial attr-set?


I did try a few approaches before sending this

1) using nesting - Did not work with existing attribute sets because 
netlink does not
allow root set (attribute-set directly used in operations) to be nested.

     name: error-event-attrs
     attributes:
       -
         name: node
         type: nest
          nested-attributes: node-attrs

2) subsetof- cannot use two parents

The only way  i could think of is to move all attrs into a superset (ie 
ras attributes)
and the rest as subsets

or

Add node id to get error counter response and reuse the response as notify
(Response - node id , error id, error name, error value)

Let me know what you think.

>
>> +        type: u32
>> +        doc: Node ID of the node that triggered the event.
>> +      -
>> +        name: node-name
>> +        type: string
>> +        doc: Node name of the node that triggered the event.
>> +      -
>> +        name: error-id
>> +        type: u32
>> +        doc: Error ID of the counter that triggered the event.
>> +      -
>> +        name: error-name
>> +        type: string
>> +        doc: Name of the error that triggered the event.
>> +      -
>> +        name: error-value
>> +        type: u32
>> +        doc: Current value of the error counter.
>>   
>>   operations:
>>     list:
>> @@ -124,3 +153,24 @@ operations:
>>         do:
>>           request:
>>             attributes: *id-attrs
>> +    -
>> +      name: error-event
>> +      doc: >-
>> +           Notify userspace of an error event.
>> +           The event includes the device, node and error information
>> +           of the error that triggered the event.
>> +      attribute-set: error-event-attrs
>> +      mcgrp: error-notify
>> +      event:
>> +        attributes:
>> +          - device-name
>> +          - node-id
>> +          - node-name
>> +          - error-id
>> +          - error-name
>> +          - error-value
>> +
>> +mcast-groups:
>> +  list:
>> +    -
>> +      name: error-notify
>> diff --git a/drivers/gpu/drm/drm_ras.c b/drivers/gpu/drm/drm_ras.c
>> index d6eab29a1394..6696ec21782e 100644
>> --- a/drivers/gpu/drm/drm_ras.c
>> +++ b/drivers/gpu/drm/drm_ras.c
>> @@ -41,6 +41,11 @@
>>    *    Userspace must provide Node ID, Error ID.
>>    *    Clears specific error counter of a node if supported.
>>    *
>> + * 4. ERROR_NOTIFY: Subscribe to this multicast group to receive error events
>> + *
>> + * 5. ERROR_EVENT: Notify userspace of an error event. The event contains device, node
>> + *    and error information that triggered the event.
>> + *
>>    * Node registration:
>>    *
>>    * - drm_ras_node_register(): Registers a new node and assigns
>> @@ -186,6 +191,34 @@ static int msg_reply_value(struct sk_buff *msg, u32 error_id,
>>   			   value);
>>   }
>>   
>> +static int msg_put_error_event_attrs(struct sk_buff *msg, struct drm_ras_node *node,
>> +				     u32 error_id, const char *error_name, u32 value)
>> +{
>> +	int ret;
>> +
>> +	ret = nla_put_string(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_DEVICE_NAME, node->device_name);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = nla_put_u32(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_NODE_ID, node->id);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = nla_put_string(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_NODE_NAME, node->node_name);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = nla_put_u32(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_ID, error_id);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = nla_put_string(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_NAME, error_name);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return nla_put_u32(msg, DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_VALUE, value);
>> +}
>> +
>>   static int doit_reply_value(struct genl_info *info, u32 node_id,
>>   			    u32 error_id)
>>   {
>> @@ -222,6 +255,59 @@ static int doit_reply_value(struct genl_info *info, u32 node_id,
>>   	return genlmsg_reply(msg, info);
>>   }
>>   
>> +/**
>> + * drm_ras_nl_error_event() - Notify listeners of an error event
>> + * @node: Node structure
>> + * @error_id: ID of the error
>> + * @error_name: Name of the error
>> + * @value: Value associated with the error
>> + * @flags: GFP flags for memory allocation
>> + *
>> + * Sends a notification to all listeners about an error event on a specific
>> + * RAS node.
>> + *
>> + * Return: 0 on success, or negative errno on failure.
>> + */
>> +int drm_ras_nl_error_event(struct drm_ras_node *node, u32 error_id, const char *error_name,
>> +			   u32 value, gfp_t flags)
>> +{
>> +	struct genl_info info;
>> +	struct sk_buff *msg;
>> +	struct nlattr *hdr;
>> +	int err = -EMSGSIZE;
> Redundant initialization, see below.
>
>> +	if (!error_name)
>> +		return -EINVAL;
>> +
>> +	if (!genl_has_listeners(&drm_ras_nl_family, &init_net, DRM_RAS_NLGRP_ERROR_NOTIFY))
>> +		return 0;
>> +
>> +	genl_info_init_ntf(&info, &drm_ras_nl_family, DRM_RAS_CMD_ERROR_EVENT);
>> +	msg = genlmsg_new(NLMSG_GOODSIZE, flags);
>> +	if (!msg)
>> +		return -ENOMEM;
>> +
>> +	hdr = genlmsg_iput(msg, &info);
> Make this part of below and return err directly.
>
>> +	if (!hdr)
>> +		goto err_free_msg;
>> +
>> +	err = msg_put_error_event_attrs(msg, node, error_id, error_name, value);
>> +	if (err)
>> +		goto err_cancel;
>> +
>> +	genlmsg_end(msg, hdr);
>> +	genlmsg_multicast(&drm_ras_nl_family, msg, 0, DRM_RAS_NLGRP_ERROR_NOTIFY, flags);
>> +	return 0;
>> +
>> +err_cancel:
>> +	genlmsg_cancel(msg, hdr);
>> +err_free_msg:
>> +	nlmsg_free(msg);
>> +	return err;
>> +}
>> +EXPORT_SYMBOL(drm_ras_nl_error_event);
>> +
>>   /**
>>    * drm_ras_nl_get_error_counter_dumpit() - Dump all Error Counters
>>    * @skb: Netlink message buffer
>> diff --git a/drivers/gpu/drm/drm_ras_nl.c b/drivers/gpu/drm/drm_ras_nl.c
>> index dea1c1b2494e..ac724bb87a3b 100644
>> --- a/drivers/gpu/drm/drm_ras_nl.c
>> +++ b/drivers/gpu/drm/drm_ras_nl.c
>> @@ -58,6 +58,10 @@ static const struct genl_split_ops drm_ras_nl_ops[] = {
>>   	},
>>   };
>>   
>> +static const struct genl_multicast_group drm_ras_nl_mcgrps[] = {
>> +	[DRM_RAS_NLGRP_ERROR_NOTIFY] = { "error-notify", },
>> +};
>> +
>>   struct genl_family drm_ras_nl_family __ro_after_init = {
>>   	.name		= DRM_RAS_FAMILY_NAME,
>>   	.version	= DRM_RAS_FAMILY_VERSION,
>> @@ -66,4 +70,6 @@ struct genl_family drm_ras_nl_family __ro_after_init = {
>>   	.module		= THIS_MODULE,
>>   	.split_ops	= drm_ras_nl_ops,
>>   	.n_split_ops	= ARRAY_SIZE(drm_ras_nl_ops),
>> +	.mcgrps		= drm_ras_nl_mcgrps,
>> +	.n_mcgrps	= ARRAY_SIZE(drm_ras_nl_mcgrps),
>>   };
>> diff --git a/drivers/gpu/drm/drm_ras_nl.h b/drivers/gpu/drm/drm_ras_nl.h
>> index a398643572a5..17e1af8cc3b3 100644
>> --- a/drivers/gpu/drm/drm_ras_nl.h
>> +++ b/drivers/gpu/drm/drm_ras_nl.h
>> @@ -21,6 +21,10 @@ int drm_ras_nl_get_error_counter_dumpit(struct sk_buff *skb,
>>   int drm_ras_nl_clear_error_counter_doit(struct sk_buff *skb,
>>   					struct genl_info *info);
>>   
>> +enum {
>> +	DRM_RAS_NLGRP_ERROR_NOTIFY,
>> +};
>> +
>>   extern struct genl_family drm_ras_nl_family;
>>   
>>   #endif /* _LINUX_DRM_RAS_GEN_H */
>> diff --git a/include/drm/drm_ras.h b/include/drm/drm_ras.h
>> index f2a787bc4f64..d4a275efdbb0 100644
>> --- a/include/drm/drm_ras.h
>> +++ b/include/drm/drm_ras.h
>> @@ -78,9 +78,14 @@ struct drm_device;
>>   #if IS_ENABLED(CONFIG_DRM_RAS)
>>   int drm_ras_node_register(struct drm_ras_node *node);
>>   void drm_ras_node_unregister(struct drm_ras_node *node);
>> +int drm_ras_nl_error_event(struct drm_ras_node *node, u32 error_id, const char *error_name,
>> +			   u32 value, gfp_t flags);
>>   #else
>>   static inline int drm_ras_node_register(struct drm_ras_node *node) { return 0; }
>>   static inline void drm_ras_node_unregister(struct drm_ras_node *node) { }
>> +static inline int drm_ras_nl_error_event(struct drm_ras_node *node, u32 error_id,
>> +					 const char *error_name, u32 value, gfp_t flags)
>> +{ return 0; }
>>   #endif
>>   
>>   #endif
>> diff --git a/include/uapi/drm/drm_ras.h b/include/uapi/drm/drm_ras.h
>> index 218a3ee86805..bb2a8a872a44 100644
>> --- a/include/uapi/drm/drm_ras.h
>> +++ b/include/uapi/drm/drm_ras.h
>> @@ -38,13 +38,28 @@ enum {
>>   	DRM_RAS_A_ERROR_COUNTER_ATTRS_MAX = (__DRM_RAS_A_ERROR_COUNTER_ATTRS_MAX - 1)
>>   };
>>   
>> +enum {
>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_DEVICE_NAME = 1,
>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_NODE_ID,
>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_NODE_NAME,
>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_ID,
>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_NAME,
>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_ERROR_VALUE,
>> +
>> +	__DRM_RAS_A_ERROR_EVENT_ATTRS_MAX,
>> +	DRM_RAS_A_ERROR_EVENT_ATTRS_MAX = (__DRM_RAS_A_ERROR_EVENT_ATTRS_MAX - 1)
>> +};
>> +
>>   enum {
>>   	DRM_RAS_CMD_LIST_NODES = 1,
>>   	DRM_RAS_CMD_GET_ERROR_COUNTER,
>>   	DRM_RAS_CMD_CLEAR_ERROR_COUNTER,
>> +	DRM_RAS_CMD_ERROR_EVENT,
>>   
>>   	__DRM_RAS_CMD_MAX,
>>   	DRM_RAS_CMD_MAX = (__DRM_RAS_CMD_MAX - 1)
>>   };
>>   
>> +#define DRM_RAS_MCGRP_ERROR_NOTIFY	"error-notify"
> Where is this used?

This is auto generated and part of UAPI. Will be used by userspace

Thanks
Riana

>
> Raag
>
>>   #endif /* _UAPI_LINUX_DRM_RAS_H */
>> -- 
>> 2.47.1
>>