Re: [PATCHv3 RFC] virtio-pci: flexible configuration layout

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Nov 23, 2011 at 01:02:22PM +1030, Rusty Russell wrote:
> +/* Fields in VIRTIO_PCI_CAP_COMMON_CFG: */
> +struct virtio_pci_common_cfg {
> +	/* About the whole device. */
> +	__u64 device_features;	/* read-only */
> +	__u64 guest_features;	/* read-write */

We currently require atomic accesses to common fields.
Some architectures might not have such for 64 bit,
so these need to be split I think ...

> +	__u64 queue_address;	/* read-write */
> +	__u16 msix_config;	/* read-write */
> +	__u8 device_status;	/* read-write */
> +	__u8 unused;
> +
> +	/* About a specific virtqueue. */
> +	__u16 queue_select;	/* read-write */
> +	__u16 queue_align;	/* read-write, power of 2. */
> +	__u16 queue_size;	/* read-write, power of 2. */
> +	__u16 queue_msix_vector;/* read-write */
> +};
>  #endif
> 
>