env: introduce SPDK_MEMZONE_NO_IOVA_CONTIG

Future DPDK versions may drop physical memory contiguity
guarantee for common memzones. DPDK 18.05 introduces
an RTE_MEMZONE_IOVA_CONTIG (0x00100000) flag, which is
documented as follows:

> RTE_MEMZONE_IOVA_CONTIG - Ensure reserved memzone is IOVA-contiguous.
>                           This option should be used when allocating
>                           memory intended for hardware rings etc.

To preserve backward compatibility, SPDK introduces an opposite
flag, SPDK_MEMZONE_NO_IOVA_CONTIG.

Change-Id: I9ea79b096fdb094051f13c9a802740b0e4ccc98e
Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/416977
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>

include/spdk/env.h

@@ -58,6 +58,11 @@ extern "C" {
  */
 #define SPDK_MALLOC_SHARE  0x02
 
+/**
+ * Memzone flags
+ */
+#define SPDK_MEMZONE_NO_IOVA_CONTIG 0x00100000 /**< no iova contiguity */
+
 struct spdk_pci_device;
 
 /**

lib/env_dpdk/env.c

@@ -138,6 +138,15 @@ spdk_memzone_reserve(const char *name, size_t len, int socket_id, unsigned flags
 	const struct rte_memzone *mz;
 	unsigned dpdk_flags = 0;
 
+#if RTE_VERSION >= RTE_VERSION_NUM(18, 05, 0, 0)
+	/* Older DPDKs do not offer such flag since their
+	 * memzones are iova-contiguous by default.
+	 */
+	if ((flags & SPDK_MEMZONE_NO_IOVA_CONTIG) == 0) {
+		dpdk_flags |= RTE_MEMZONE_IOVA_CONTIG;
+	}
+#endif
+
 	if (socket_id == SPDK_ENV_SOCKET_ID_ANY) {
 		socket_id = SOCKET_ID_ANY;
 	}

lib/nvme/nvme.c

@@ -305,7 +305,8 @@ nvme_driver_init(void)
 			return 0;
 		} else {
 			g_spdk_nvme_driver = spdk_memzone_reserve(SPDK_NVME_DRIVER_NAME,
-					     sizeof(struct nvme_driver), socket_id, 0);
+					     sizeof(struct nvme_driver), socket_id,
+					     SPDK_MEMZONE_NO_IOVA_CONTIG);
 		}
 
 		if (g_spdk_nvme_driver == NULL) {