VirtioUsed
queueMemSize += ROUNDUP(sizeof(VirtioUsed) + sizeof(VirtioUsedItem) * fQueueLen, B_PAGE_SIZE);
fUsed = (VirtioUsed*) (queueMem + usedOffset);
volatile VirtioUsed *fUsed;
fUsed = (VirtioUsed*)aligned_malloc(sizeof(VirtioUsed)
memset(fUsed, 0, sizeof(VirtioUsed) + sizeof(VirtioUsedItem) * fQueueLen);
VirtioUsed* volatile fUsed;