[dpdk-dev] [PATCH 7/7] net/virtio: introduce Vhost-vDPA backend

[Fu, Patrick]

> -----Original Message-----
> From: Xia, Chenbo <chenbo.xia at intel.com>
> Sent: Thursday, September 24, 2020 1:26 PM
> To: Maxime Coquelin <maxime.coquelin at redhat.com>; dev at dpdk.org; Fu,
> Patrick <patrick.fu at intel.com>; amorenoz at redhat.com
> Subject: RE: [dpdk-dev] [PATCH 7/7] net/virtio: introduce Vhost-vDPA
> backend
> 
> Hi Maxime,
> 
> > +
> > +/**
> > + * Set up environment to talk with a vhost vdpa backend.
> > + *
> > + * @return
> > + *   - (-1) if fail to set up;
> > + *   - (>=0) if successful.
> > + */
> > +static int
> > +vhost_vdpa_setup(struct virtio_user_dev *dev)
> > +{
> > +	uint32_t did = (uint32_t)-1;
> 
> I see in kernel, 'did' should be u8:
> 
> static long vhost_vdpa_get_device_id(struct vhost_vdpa *v, u8 __user *argp)
> 
> So I think here did should be uint8_t?
> 

Actually `did` is u32 in kernel. argp is just a user pointer. Whether it's u8* or u32* has nothing to do with the `did` data size 

refer to control code def:
#define VHOST_VDPA_GET_DEVICE_ID	_IOR(VHOST_VIRTIO, 0x70, __u32)

Thanks,

Patrick