From a586d4f6016f7139d8c26df0e6927131168d3b5b Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 4 Feb 2008 23:49:56 -0500 Subject: virtio: simplify config mechanism. Previously we used a type/len pair within the config space, but this seems overkill. We now simply define a structure which represents the layout in the config space: the config space can now only be extended at the end. The main driver-visible changes: 1) We indicate what fields are present with an explicit feature bit. 2) Virtqueues are explicitly numbered, and not in the config space. Signed-off-by: Rusty Russell --- include/linux/lguest_launcher.h | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'include/linux/lguest_launcher.h') diff --git a/include/linux/lguest_launcher.h b/include/linux/lguest_launcher.h index 697104da91f..589be3e1f3a 100644 --- a/include/linux/lguest_launcher.h +++ b/include/linux/lguest_launcher.h @@ -23,7 +23,12 @@ struct lguest_device_desc { /* The device type: console, network, disk etc. Type 0 terminates. */ __u8 type; - /* The number of bytes of the config array. */ + /* The number of virtqueues (first in config array) */ + __u8 num_vq; + /* The number of bytes of feature bits. Multiply by 2: one for host + * features and one for guest acknowledgements. */ + __u8 feature_len; + /* The number of bytes of the config array after virtqueues. */ __u8 config_len; /* A status byte, written by the Guest. */ __u8 status; @@ -31,7 +36,7 @@ struct lguest_device_desc { }; /*D:135 This is how we expect the device configuration field for a virtqueue - * (type VIRTIO_CONFIG_F_VIRTQUEUE) to be laid out: */ + * to be laid out in config space. */ struct lguest_vqconfig { /* The number of entries in the virtio_ring */ __u16 num; -- cgit v1.2.3