[dpdk-dev] [PATCH v2 5/7] mem: modify error message for DMA mask check

[Li, WenjieX A]

1. With GCC32, testpmd could not startup without '--iova-mode pa'.
./i686-native-linuxapp-gcc/app/testpmd -c f -n 4 -- -i
The output is:
EAL: Detected 16 lcore(s)
EAL: Detected 1 NUMA nodes
EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
EAL: Some devices want iova as va but pa will be used because.. EAL: few device bound to UIO
EAL: No free hugepages reported in hugepages-1048576kB
EAL: Probing VFIO support...
EAL: VFIO support initialized
EAL: wrong dma mask size 48 (Max: 31)
EAL: alloc_pages_on_heap(): couldn't allocate memory due to IOVA exceeding limits of current DMA mask
error allocating rte services array
EAL: FATAL: rte_service_init() failed
EAL: rte_service_init() failed
PANIC in main():
Cannot init EAL
5: [./i686-native-linuxapp-gcc/app/testpmd(+0x95fda) [0x56606fda]]
4: [/lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf6) [0xf74d1276]]
3: [./i686-native-linuxapp-gcc/app/testpmd(main+0xf21) [0x565fcee1]]
2: [./i686-native-linuxapp-gcc/app/testpmd(__rte_panic+0x3d) [0x565edc68]]
1: [./i686-native-linuxapp-gcc/app/testpmd(rte_dump_stack+0x33) [0x5675f333]]
Aborted

2. With '--iova-mode pa', testpmd could startup.
3. With GCC64, there is no such issue.
Thanks!


-----Original Message-----
From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Alejandro Lucero
Sent: Friday, November 2, 2018 3:53 AM
To: dev at dpdk.org
Subject: [dpdk-dev] [PATCH v2 5/7] mem: modify error message for DMA mask check

If DMA mask checks shows mapped memory out of the supported range specified by the DMA mask, nothing can be done but return an error an report the error. This can imply the app not being executed at all or precluding dynamic memory allocation once the app is running.
In any case, we can advice the user to force IOVA as PA if currently IOVA being VA and user being root.

Signed-off-by: Alejandro Lucero <alejandro.lucero at netronome.com>
Tested-by: Li, WenjieX A <wenjiex.a.li at intel.com>
---
 lib/librte_eal/common/malloc_heap.c | 41 +++++++++++++++++++++++++----
 1 file changed, 36 insertions(+), 5 deletions(-)

diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c
index 4997c5ef5..c2c112aa6 100644
--- a/lib/librte_eal/common/malloc_heap.c
+++ b/lib/librte_eal/common/malloc_heap.c
@@ -321,13 +321,44 @@ alloc_pages_on_heap(struct malloc_heap *heap, uint64_t pg_sz, size_t elt_size,
 		goto fail;
 	}
 
-	if (mcfg->dma_maskbits) {
-		if (rte_mem_check_dma_mask(mcfg->dma_maskbits)) {
+	/*
+	 * Once we have all the memseg lists configured, if there is a dma mask
+	 * set, check iova addresses are not out of range. Otherwise the device
+	 * setting the dma mask could have problems with the mapped memory.
+	 *
+	 * There are two situations when this can happen:
+	 *	1) memory initialization
+	 *	2) dynamic memory allocation
+	 *
+	 * For 1), an error when checking dma mask implies app can not be
+	 * executed. For 2) implies the new memory can not be added.
+	 */
+	if (mcfg->dma_maskbits &&
+	    rte_mem_check_dma_mask(mcfg->dma_maskbits)) {
+		/*
+		 * Currently this can only happen if IOMMU is enabled
+		 * and the address width supported by the IOMMU hw is
+		 * not enough for using the memory mapped IOVAs.
+		 *
+		 * If IOVA is VA, advice to try with '--iova-mode pa'
+		 * which could solve some situations when IOVA VA is not
+		 * really needed.
+		 */
+		RTE_LOG(ERR, EAL,
+			"%s(): couldn't allocate memory due to IOVA exceeding limits of current DMA mask\n",
+			__func__);
+
+		/*
+		 * If IOVA is VA and it is possible to run with IOVA PA,
+		 * because user is root, give and advice for solving the
+		 * problem.
+		 */
+		if ((rte_eal_iova_mode() == RTE_IOVA_VA) &&
+		     rte_eal_using_phys_addrs())
 			RTE_LOG(ERR, EAL,
-				"%s(): couldn't allocate memory due to DMA mask\n",
+				"%s(): Please try initializing EAL with --iova-mode=pa 
+parameter\n",
 				__func__);
-			goto fail;
-		}
+		goto fail;
 	}
 
 	/* add newly minted memsegs to malloc heap */
--
2.17.1