[lab6] drivers/virtio: add queue_align configure

os/lab6/drivers/virtio/virtio_mmio.c

@@ -38,6 +38,7 @@ void virtio_set_queue(struct virtio_device *device, uint64_t is_legacy, uint32_t
     device->queue_num = VIRTQ_RING_NUM;
     // 6. set the queue address
     if(is_legacy) {
+        device->queue_align = PAGE_SIZE;
         device->guest_page_size = PAGE_SIZE;
         device->queue_pfn = virtq_phy_addr / PAGE_SIZE;
     } else {

os/lab6/include/device/virtio/virtio_queue.h

@@ -92,6 +92,8 @@ struct virtq {
     uint64_t physical_addr;
 };
 
+#define VIRTQ_ALIGN(x) (((x) + PAGE_SIZE) & ~PAGE_SIZE)
+
 uint16_t virtq_get_desc(struct virtq *vq);
 void virtq_free_desc(struct virtq *vq, uint16_t idx);
 void virtq_free_desc_chain(struct virtq *vq, uint16_t idx);