Re: [RFC PATCH] virtio: change config to guest endian.

[Christian Borntraeger <borntraeger@de.ibm.com>]

Am Dienstag, 22. April 2008 schrieb Rusty Russell:
> [Christian, Hollis, how much is this ABI breakage going to hurt you?]

It is ok for s390 at the moment. We are still working on making userspace 
ready and I plan to change the guest<->host for s390 anyway. I try to make 
these changes for drivers/s390/kvm/kvm_virtio.c before 2.6.26. The main 
reason is, that we are currently limited to around 80 devices. I am not sure, 
if I should change the allocation of the virtqueues and descriptors to guest 
memory as well. 

Back to your patch:
I have still some ideas about virtio between little endian and big endian 
systems, but it requires more and different marshalling anyway - even on 
driver level. No idea yet how to solve that properly.

Consider your change
Acked-by: Christian Bornraeger <borntraeger@de.ibm.com>
given that you fix the issue below:

[...]
> --- a/drivers/virtio/virtio_balloon.c	Sun Apr 20 14:41:02 2008 +1000
> +++ b/drivers/virtio/virtio_balloon.c	Sun Apr 20 15:07:45 2008 +1000
> @@ -155,9 +155,9 @@ static inline s64 towards_target(struct 
>  static inline s64 towards_target(struct virtio_balloon *vb)
>  {
>  	u32 v;
> -	__virtio_config_val(vb->vdev,
> -			    offsetof(struct virtio_balloon_config, num_pages),
> -			    &v);
> +	vb->vdev->config->get(vb->vdev,
> +			      offsetof(struct virtio_balloon_config, num_pages),
> +			      &v);

this is missing a sizeof(v), no?

Christian

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