virtio-scsi: finalize IOMMU support

After converting to use DMA api for virtio devices, we should use
dma_as instead of address_space_memory. Otherwise it won't work if
IOMMU is enabled.

Fixes: commit 8607f5c3 ("virtio: convert to use DMA api")
Cc: qemu-stable@nongnu.org
Signed-off-by: NJason Wang <jasowang@redhat.com>
Message-Id: <1499170866-9068-1-git-send-email-jasowang@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 025bdeab)
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

hw/scsi/virtio-scsi.c

@@ -43,12 +43,13 @@ static inline SCSIDevice *virtio_scsi_device_find(VirtIOSCSI *s, uint8_t *lun)
 
 void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req)
 {
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
     const size_t zero_skip =
         offsetof(VirtIOSCSIReq, resp_iov) + sizeof(req->resp_iov);
 
     req->vq = vq;
     req->dev = s;
-    qemu_sglist_init(&req->qsgl, DEVICE(s), 8, &address_space_memory);
+    qemu_sglist_init(&req->qsgl, DEVICE(s), 8, vdev->dma_as);
     qemu_iovec_init(&req->resp_iov, 1);
     memset((uint8_t *)req + zero_skip, 0, sizeof(*req) - zero_skip);
 }