[PATCH v2] app/dma-perf: fix physical address seg-fault

[Vipin Varghese <vipin.varghese@amd.com>]

do_cpu_mem_copy uses DPDK API rte_mbuf_data_iova to return
the start of the virtual address for both src and dst.
But in case of iova mode set as PA, this results in seg-fault.
This is because rte_memcpy uses VA address and not PA.

This fix invokes `rte_pktmbuf_mtod` for both src and dst.

Bugzilla ID: 1269
Fixes: 623dc9364dc6 ("app/dma-perf: introduce DMA performance test")
Cc: cheng1.jiang@intel.com

Cc: stable@dpdk.org

Signed-off-by: Vipin Varghese <vipin.varghese@amd.com>
Suggested-by: Anoob Joseph <anoobj@marvell.com>
---

v2:
 - suggest use of pktmbuf_mtod for both va and pa.

tested for both va and pa

CMD:
PA: dpdk-test-dma-perf --iova-mode=pa  -- --config test.ini
VA: dpdk-test-dma-perf --iova-mode=va  -- --config test.ini
DC: dpdk-test-dma-perf --iova-mode=dc  -- --config test.ini

Log: fails for dc mode `EAL: invalid parameters for --iova-mode`

test.ini:
```
[case1]
type=CPU_MEM_COPY
mem_size=10
buf_size=64,8192,2,MUL
src_numa_node=0
dst_numa_node=0
cache_flush=0
test_seconds=2
lcore = 7
eal_args=--in-memory --no-pci
```
---
 app/test-dma-perf/benchmark.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/app/test-dma-perf/benchmark.c b/app/test-dma-perf/benchmark.c
index 0601e0d171..9059253057 100644
--- a/app/test-dma-perf/benchmark.c
+++ b/app/test-dma-perf/benchmark.c
@@ -288,9 +288,12 @@ do_cpu_mem_copy(void *p)
 
 	while (1) {
 		for (i = 0; i < nr_buf; i++) {
+			void *src = rte_pktmbuf_mtod(dsts[i], void *);
+			void *dst = rte_pktmbuf_mtod(srcs[i], void *);
+
 			/* copy buffer form src to dst */
-			rte_memcpy((void *)(uintptr_t)rte_mbuf_data_iova(dsts[i]),
-				(void *)(uintptr_t)rte_mbuf_data_iova(srcs[i]),
+			rte_memcpy(dst,
+				src,
 				(size_t)buf_size);
 			worker_info->total_cpl++;
 		}
-- 
2.34.1