Define a new feature bit for the host to declare that it uses an avail_event index (like Xen) instead of a feature bit to enable/disable interrupts. Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> --- include/linux/virtio_ring.h | 11 ++++++++--- 1 files changed, 8 insertions(+), 3 deletions(-) diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h index f5c1b75..f791772 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -32,6 +32,9 @@ /* The Guest publishes the used index for which it expects an interrupt * at the end of the avail ring. Host should ignore the avail->flags field. */ #define VIRTIO_RING_F_USED_EVENT_IDX 29 +/* The Host publishes the avail index for which it expects a kick + * at the end of the used ring. Guest should ignore the used->flags field. */ +#define VIRTIO_RING_F_AVAIL_EVENT_IDX 32 /* Virtio ring descriptors: 16 bytes. These can chain together via "next". */ struct vring_desc { @@ -96,11 +99,13 @@ struct vring { * __u16 used_flags; * __u16 used_idx; * struct vring_used_elem used[num]; + * __u16 avail_event_idx; * }; */ -/* We publish the used event index at the end of the available ring. - * It is at the end for backwards compatibility. */ +/* We publish the used event index at the end of the available ring, and vice + * versa. They are at the end for backwards compatibility. */ #define vring_used_event(vr) ((vr)->avail->ring[(vr)->num]) +#define vring_avail_event(vr) (*(__u16 *)&(vr)->used->ring[(vr)->num]) static inline void vring_init(struct vring *vr, unsigned int num, void *p, unsigned long align) @@ -116,7 +121,7 @@ static inline unsigned vring_size(unsigned int num, unsigned long align) { return ((sizeof(struct vring_desc) * num + sizeof(__u16) * (2 + num) + align - 1) & ~(align - 1)) - + sizeof(__u16) * 2 + sizeof(struct vring_used_elem) * num; + + sizeof(__u16) * 3 + sizeof(struct vring_used_elem) * num; } #ifdef __KERNEL__ -- 1.7.5.53.gc233e -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html