Struct VirtqUsed 

#[repr(C)]
pub struct VirtqUsed {
    pub flags: u16,
    pub idx: u16,
    pub ring: [VirtqUsedElem; 256],
}

Used ring: device writes completed descriptor chain heads here.

Fields

flags: u16

Flags (e.g., VIRTQ_USED_F_NO_NOTIFY to suppress available-buffer notifications)

idx: u16

Index of the next entry the device will write to in ring[]

ring: [VirtqUsedElem; 256]

Ring of completed descriptor chain elements