On 7/13/21 10:37 PM, Jason Wang wrote:
>
> 在 2021/7/12 下午6:35, Jonah Palmer 写道:
>> From: Laurent Vivier <lvivier@redhat.com>
>>
>> This new command shows internal status of a VirtQueue.
>> (vrings and indexes).
>>
>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>> Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
>> ---
>>   hw/virtio/virtio-stub.c |   6 +++
>>   hw/virtio/virtio.c      |  37 ++++++++++++++++++
>>   qapi/virtio.json        | 102 
>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 145 insertions(+)
>>
>>   [Jonah: Added 'device-type' field to VirtQueueStatus and
>>   qmp command x-debug-virtio-queue-status.]
>>
>> diff --git a/hw/virtio/virtio-stub.c b/hw/virtio/virtio-stub.c
>> index ddb592f..3c1bf17 100644
>> --- a/hw/virtio/virtio-stub.c
>> +++ b/hw/virtio/virtio-stub.c
>> @@ -17,3 +17,9 @@ VirtioStatus *qmp_x_debug_virtio_status(const char* 
>> path, Error **errp)
>>   {
>>       return qmp_virtio_unsupported(errp);
>>   }
>> +
>> +VirtQueueStatus *qmp_x_debug_virtio_queue_status(const char *path,
>> +                                                 uint16_t queue, 
>> Error **errp)
>> +{
>> +    return qmp_virtio_unsupported(errp);
>> +}
>> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
>> index 81a0ee8..ccd4371 100644
>> --- a/hw/virtio/virtio.c
>> +++ b/hw/virtio/virtio.c
>> @@ -3935,6 +3935,43 @@ static VirtIODevice *virtio_device_find(const 
>> char *path)
>>       return NULL;
>>   }
>>   +VirtQueueStatus *qmp_x_debug_virtio_queue_status(const char *path,
>> +                                                 uint16_t queue, 
>> Error **errp)
>> +{
>> +    VirtIODevice *vdev;
>> +    VirtQueueStatus *status;
>> +
>> +    vdev = virtio_device_find(path);
>> +    if (vdev == NULL) {
>> +        error_setg(errp, "Path %s is not a VirtIO device", path);
>> +        return NULL;
>> +    }
>> +
>> +    if (queue >= VIRTIO_QUEUE_MAX || !virtio_queue_get_num(vdev, 
>> queue)) {
>> +        error_setg(errp, "Invalid virtqueue number %d", queue);
>> +        return NULL;
>> +    }
>> +
>> +    status = g_new0(VirtQueueStatus, 1);
>> +    status->device_type = qapi_enum_parse(&VirtioType_lookup, 
>> vdev->name,
>> +                                          VIRTIO_TYPE_UNKNOWN, NULL);
>> +    status->queue_index = vdev->vq[queue].queue_index;
>> +    status->inuse = vdev->vq[queue].inuse;
>> +    status->vring_num = vdev->vq[queue].vring.num;
>> +    status->vring_num_default = vdev->vq[queue].vring.num_default;
>> +    status->vring_align = vdev->vq[queue].vring.align;
>> +    status->vring_desc = vdev->vq[queue].vring.desc;
>> +    status->vring_avail = vdev->vq[queue].vring.avail;
>> +    status->vring_used = vdev->vq[queue].vring.used;
>> +    status->last_avail_idx = vdev->vq[queue].last_avail_idx;
>
>
> As mentioned in previous versions. We need add vhost support otherwise 
> the value here is wrong.

Got it. I'll add a case to determine if vhost is active for a given device.
So, in the case that vhost is active, should I just not print out the value or would I substitute it with
another value (whatever that might be)? Same question for shadow_avail_idx below as well.

Jonah

>
>
>> +    status->shadow_avail_idx = vdev->vq[queue].shadow_avail_idx;
>
>
> The shadow index is something that is implementation specific e.g in 
> the case of vhost it's kind of meaningless.
>
> Thanks
>
>
>> +    status->used_idx = vdev->vq[queue].used_idx;
>> +    status->signalled_used = vdev->vq[queue].signalled_used;
>> +    status->signalled_used_valid = 
>> vdev->vq[queue].signalled_used_valid;
>> +
>> +    return status;
>> +}
>> +
>>   #define CONVERT_FEATURES(type, map)                \
>>       ({                                           \
>>           type *list = NULL;                         \
>> diff --git a/qapi/virtio.json b/qapi/virtio.json
>> index 78873cd..7007e0c 100644
>> --- a/qapi/virtio.json
>> +++ b/qapi/virtio.json
>> @@ -406,3 +406,105 @@
>>     'data': { 'path': 'str' },
>>     'returns': 'VirtioStatus'
>>   }
>> +
>> +##
>> +# @VirtQueueStatus:
>> +#
>> +# Status of a VirtQueue
>> +#
>> +# @device-type: VirtIO device type
>> +#
>> +# @queue-index: VirtQueue queue_index
>> +#
>> +# @inuse: VirtQueue inuse
>> +#
>> +# @vring-num: VirtQueue vring.num
>> +#
>> +# @vring-num-default: VirtQueue vring.num_default
>> +#
>> +# @vring-align: VirtQueue vring.align
>> +#
>> +# @vring-desc: VirtQueue vring.desc
>> +#
>> +# @vring-avail: VirtQueue vring.avail
>> +#
>> +# @vring-used: VirtQueue vring.used
>> +#
>> +# @last-avail-idx: VirtQueue last_avail_idx
>> +#
>> +# @shadow-avail-idx: VirtQueue shadow_avail_idx
>> +#
>> +# @used-idx: VirtQueue used_idx
>> +#
>> +# @signalled-used: VirtQueue signalled_used
>> +#
>> +# @signalled-used-valid: VirtQueue signalled_used_valid
>> +#
>> +# Since: 6.1
>> +#
>> +##
>> +
>> +{ 'struct': 'VirtQueueStatus',
>> +  'data': {
>> +    'device-type': 'VirtioType',
>> +    'queue-index': 'uint16',
>> +    'inuse': 'uint32',
>> +    'vring-num': 'int',
>> +    'vring-num-default': 'int',
>> +    'vring-align': 'int',
>> +    'vring-desc': 'uint64',
>> +    'vring-avail': 'uint64',
>> +    'vring-used': 'uint64',
>> +    'last-avail-idx': 'uint16',
>> +    'shadow-avail-idx': 'uint16',
>> +    'used-idx': 'uint16',
>> +    'signalled-used': 'uint16',
>> +    'signalled-used-valid': 'uint16'
>> +  }
>> +}
>> +
>> +##
>> +# @x-debug-virtio-queue-status:
>> +#
>> +# Return the status of a given VirtQueue
>> +#
>> +# @path: QOBject path of the VirtIODevice
>> +#
>> +# @queue: queue number to examine
>> +#
>> +# Returns: Status of the VirtQueue
>> +#
>> +# Since: 6.1
>> +#
>> +# Example:
>> +#
>> +# -> { "execute": "x-debug-virtio-queue-status",
>> +#      "arguments": {
>> +#          "path": "/machine/peripheral-anon/device[3]/virtio-backend",
>> +#          "queue": 0
>> +#      }
>> +#   }
>> +# <- { "return": {
>> +#      "signalled-used": 373,
>> +#      "inuse": 0,
>> +#      "vring-align": 4096,
>> +#      "vring-desc": 864411648,
>> +#      "signalled-used-valid": 0,
>> +#      "vring-num-default": 256,
>> +#      "vring-avail": 864415744,
>> +#      "queue-index": 0,
>> +#      "last-avail-idx": 373,
>> +#      "vring-used": 864416320,
>> +#      "used-idx": 373,
>> +#      "device-type": "virtio-net",
>> +#      "shadow-avail-idx": 619,
>> +#      "vring-num": 256
>> +#      }
>> +#    }
>> +#
>> +##
>> +
>> +{ 'command': 'x-debug-virtio-queue-status',
>> +  'data': { 'path': 'str', 'queue': 'uint16' },
>> +  'returns': 'VirtQueueStatus'
>> +}
>