iommu/vt-d: Use correct domain id to flush virtual machine domains

For virtual machine domains, domain->id is a virtual id, and the real
domain id written into context entry is dynamically allocated.
So use the real domain id instead of domain->id when flushing iotlbs
for virtual machine domains.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 147ab1c..d77009b 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1822,7 +1822,7 @@
 					   (((u16)bus) << 8) | devfn,
 					   DMA_CCMD_MASK_NOBIT,
 					   DMA_CCMD_DEVICE_INVL);
-		iommu->flush.flush_iotlb(iommu, domain->id, 0, 0, DMA_TLB_DSI_FLUSH);
+		iommu->flush.flush_iotlb(iommu, id, 0, 0, DMA_TLB_DSI_FLUSH);
 	} else {
 		iommu_flush_write_buffer(iommu);
 	}