Re: [PATCHv4 2/2] vhost_net: a kernel-level virtio server

From: Michael S. Tsirkin
Date: Thu Aug 27 2009 - 06:12:46 EST


On Wed, Aug 26, 2009 at 03:40:59PM +0200, Arnd Bergmann wrote:
> On Tuesday 25 August 2009, Michael S. Tsirkin wrote:
> > > I'd like to avoid that here,
> > > though it's kind of ugly. We'd need VHOST_GET_FEATURES (and ACK) to take a
> > > struct like:
> > >
> > > u32 feature_size;
> > > u32 features[];
>
> Hmm, variable length ioctl arguments, I'd rather not go there.
> The ioctl infrastructure already has a length argument encoded
> in the ioctl number. We can use that if we need more, e.g.
>
> /* now */
> #define VHOST_GET_FEATURES _IOR(VHOST_VIRTIO, 0x00, __u64)
> /*
> * uncomment if we run out of feature bits:
>
> struct vhost_get_features2 {
> __u64 bits[2];
> };
> #define VHOST_GET_FEATURES2 _IOR(VHOST_VIRTIO, 0x00, \
> struct vhost_get_features2)
> */


I thought so, too. Rusty, agree?

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MST
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