Re: [RFC 1/2] vduse: validate block features only with block devices

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 4/20/23 06:06, Jason Wang wrote:
> On Wed, Apr 19, 2023 at 9:43 PM Maxime Coquelin
> <maxime.coquelin@redhat.com> wrote:
>>
>> This patch is preliminary work to enable network device
>> type support to VDUSE.
>>
>> As VIRTIO_BLK_F_CONFIG_WCE shares the same value as
>> VIRTIO_NET_F_HOST_TSO4, we need to restrict its check
>> to Virtio-blk device type.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>   drivers/vdpa/vdpa_user/vduse_dev.c | 9 +++++----
>>   1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
>> index 0c3b48616a9f..6fa598a03d8e 100644
>> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
>> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
>> @@ -1416,13 +1416,14 @@ static bool device_is_allowed(u32 device_id)
>>          return false;
>>   }
>>
>> -static bool features_is_valid(u64 features)
>> +static bool features_is_valid(struct vduse_dev_config *config)
>>   {
>> -       if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
>> +       if (!(config->features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
>>                  return false;
>>
>>          /* Now we only support read-only configuration space */
>> -       if (features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE))
>> +       if ((config->device_id == VIRTIO_ID_BLOCK) &&
>> +                       (config->features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE)))
> 
> The reason we filter WCE out is to avoid writable config space which
> might block the driver with a buggy userspace.
> 
> For networking, I guess we should fail if VERSION_1 is not negotiated,
> then we can avoid setting mac addresses via the config space.

  Ok, I will add it to patch 2 in V1.

Thanks,
Maxime

> 
> Thanks
> 
>>                  return false;
>>
>>          return true;
>> @@ -1446,7 +1447,7 @@ static bool vduse_validate_config(struct vduse_dev_config *config)
>>          if (!device_is_allowed(config->device_id))
>>                  return false;
>>
>> -       if (!features_is_valid(config->features))
>> +       if (!features_is_valid(config))
>>                  return false;
>>
>>          return true;
>> --
>> 2.39.2
>>
>