From adf3cc2bc84d78664d6152596a4ac6f1b1c4badd Mon Sep 17 00:00:00 2001
From: Daniel Verkamp <daniel.verkamp@intel.com>
Date: Thu, 1 Jun 2017 18:12:29 -0700
Subject: [PATCH] vhost: add fallback if linux/vfio.h is missing

On older kernels that don't have VFIO, stub out the vhost IOMMU
functions.

Fixes build on older distributions (e.g. CentOS 6).

Change-Id: Icda9998e494c24d252511a4da93ecb56502fe5a7
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/363473
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
---
 lib/vhost/vhost_iommu.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/lib/vhost/vhost_iommu.c b/lib/vhost/vhost_iommu.c
index 8b50e7922..a785e3316 100644
--- a/lib/vhost/vhost_iommu.c
+++ b/lib/vhost/vhost_iommu.c
@@ -33,6 +33,12 @@
 
 #include "spdk/stdinc.h"
 
+#include "vhost_iommu.h"
+
+#include <linux/version.h>
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 6, 0)
+
 #include <linux/vfio.h>
 
 #include "spdk/env.h"
@@ -40,8 +46,6 @@
 
 #include "spdk_internal/log.h"
 
-#include "vhost_iommu.h"
-
 struct vfio_map {
 	uint64_t iova;
 	uint64_t size;
@@ -303,3 +307,19 @@ int spdk_iommu_mem_unregister(uint64_t addr, uint64_t len)
 }
 
 SPDK_LOG_REGISTER_TRACE_FLAG("vhost_vfio", SPDK_TRACE_VHOST_VFIO)
+
+#else
+
+/* linux/vfio.h not available */
+
+int spdk_iommu_mem_register(uint64_t addr, uint64_t len)
+{
+	return 0;
+}
+
+int spdk_iommu_mem_unregister(uint64_t addr, uint64_t len)
+{
+	return 0;
+}
+
+#endif