On Thu, 2011-12-08 at 21:04 +1030, Rusty Russell wrote:
> Based on patch by Michael S. Tsirkin <mst@xxxxxxxxxx>, but I found it
> hard to follow so changed to use structures which are more
> self-documenting.
>
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> ---
> include/linux/virtio_pci.h | 41 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 41 insertions(+)
>
> diff --git a/include/linux/virtio_pci.h b/include/linux/virtio_pci.h
> --- a/include/linux/virtio_pci.h
> +++ b/include/linux/virtio_pci.h
> @@ -92,4 +92,45 @@
> /* The alignment to use between consumer and producer parts of vring.
> * x86 pagesize again. */
> #define VIRTIO_PCI_VRING_ALIGN 4096
> +
> +/* IDs for different capabilities. Must all exist. */
> +/* FIXME: Do we win from separating ISR, NOTIFY and COMMON? */
> +/* Common configuration */
> +#define VIRTIO_PCI_CAP_COMMON_CFG 1
> +/* Notifications */
> +#define VIRTIO_PCI_CAP_NOTIFY_CFG 2
> +/* ISR access */
> +#define VIRTIO_PCI_CAP_ISR_CFG 3
> +/* Device specific confiuration */
> +#define VIRTIO_PCI_CAP_DEVICE_CFG 4
> +
> +/* This is the PCI capability header: */
> +struct virtio_pci_cap {
> + u8 cap_vndr; /* Generic PCI field: PCI_CAP_ID_VNDR */
> + u8 cap_next; /* Generic PCI field: next ptr. */
There should be a cap_len field here, which is mandatory for
PCI_CAP_ID_VNDR capabilities.
> + u8 cfg_type; /* One of the VIRTIO_PCI_CAP_*_CFG. */
> +/* FIXME: Should we use a bir, instead of raw bar number? */
> + u8 bar; /* Where to find it. */
> + __le32 offset; /* Offset within bar. */
> + __le32 length; /* Length. */
> +};
> +
> +/* Fields in VIRTIO_PCI_CAP_COMMON_CFG: */
> +struct virtio_pci_common_cfg {
> + /* About the whole device. */
> + __le32 device_feature_select; /* read-write */
> + __le32 device_feature; /* read-only */
> + __le32 guest_feature_select; /* read-write */
> + __le32 guest_feature; /* read-only */
> + __le16 msix_config; /* read-write */
> + __u8 device_status; /* read-write */
> + __u8 unused;
> +
> + /* About a specific virtqueue. */
> + __le16 queue_select; /* read-write */
> + __le16 queue_align; /* read-write, power of 2. */
> + __le16 queue_size; /* read-write, power of 2. */
> + __le16 queue_msix_vector;/* read-write */
> + __le64 queue_address; /* read-write: 0xFFFFFFFFFFFFFFFF == DNE. */
This is now a 64bit address, but we can't do an atomic iowrite64(). We
should make it clear to the device when it should initialize the vq.
--
Sasha.
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