From: Jonas Pfefferle <jpf@zurich.ibm.com>
Date: Tue, 31 Oct 2017 15:59:46 +0000 (+0100)
Subject: vfio: improve noiommu check error handling
X-Git-Tag: spdx-start~133
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=de4a79cf56bec0623f7f73ca82a2cff15f1f38e3;p=dpdk.git

vfio: improve noiommu check error handling

Kernels v4.4 and earlier does have vfio, but not
the noiommu mode, so the file does not exist.

Check and report errors on open/read in noiommu check.

Signed-off-by: Jonas Pfefferle <jpf@zurich.ibm.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---

diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c b/lib/librte_eal/linuxapp/eal/eal_vfio.c
index 5371ec23b3..e44ae4d04a 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
@@ -814,20 +814,33 @@ vfio_noiommu_dma_map(int __rte_unused vfio_container_fd)
 int
 rte_vfio_noiommu_is_enabled(void)
 {
-	int fd, ret, cnt __rte_unused;
+	int fd;
+	ssize_t cnt;
 	char c;
 
-	ret = -1;
 	fd = open(VFIO_NOIOMMU_MODE, O_RDONLY);
-	if (fd < 0)
-		return -1;
+	if (fd < 0) {
+		if (errno != ENOENT) {
+			RTE_LOG(ERR, EAL, "  cannot open vfio noiommu file %i (%s)\n",
+					errno, strerror(errno));
+			return -1;
+		}
+		/*
+		 * else the file does not exists
+		 * i.e. noiommu is not enabled
+		 */
+		return 0;
+	}
 
 	cnt = read(fd, &c, 1);
-	if (c == 'Y')
-		ret = 1;
-
 	close(fd);
-	return ret;
+	if (cnt != 1) {
+		RTE_LOG(ERR, EAL, "  unable to read from vfio noiommu "
+				"file %i (%s)\n", errno, strerror(errno));
+		return -1;
+	}
+
+	return c == 'Y';
 }
 
 #endif