[dpdk-dev] [PATCH v2] net/virtio: avoid annoying IOPL call related errors

[Ilya Maximets]

In case of running with not enough capabilities, i.e. running as
non-root user any application linked with DPDK prints the message
about IOPL call failure even if it was just called like
'./testpmd --help'. For example, this beaks most of the OVS unit
tests if it built with DPDK support.

Let's register the virtio driver unconditionally and print error
message while probing the device. Silent iopl() call left in the
constructor to have privileges as early as possible as it was before.

Signed-off-by: Ilya Maximets <i.maxim...@samsung.com>
---

Version 2:
        * Fixed possible fd leak on BSD.

We can avoid test failures in OVS by filtering the output
like this:
  https://patchwork.ozlabs.org/project/openvswitch/list/?series=77706

But it still looks very inconvenient for me to have this
message in the output of every command for the DPDK linked app.

 drivers/net/virtio/virtio_ethdev.c | 11 ++++++-----
 lib/librte_eal/bsdapp/eal/eal.c    |  6 ++++--
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c 
b/drivers/net/virtio/virtio_ethdev.c
index e1fe36a23..2ba66d291 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1760,6 +1760,11 @@ vdpa_mode_selected(struct rte_devargs *devargs)
 static int eth_virtio_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
        struct rte_pci_device *pci_dev)
 {
+       if (rte_eal_iopl_init() != 0) {
+               PMD_INIT_LOG(ERR, "IOPL call failed - cannot use virtio PMD");
+               return 1;
+       }
+
        /* virtio pmd skips probe if device needs to work in vdpa mode */
        if (vdpa_mode_selected(pci_dev->device.devargs))
                return 1;
@@ -1785,11 +1790,7 @@ static struct rte_pci_driver rte_virtio_pmd = {
 
 RTE_INIT(rte_virtio_pmd_init)
 {
-       if (rte_eal_iopl_init() != 0) {
-               PMD_INIT_LOG(ERR, "IOPL call failed - cannot use virtio PMD");
-               return;
-       }
-
+       rte_eal_iopl_init();
        rte_pci_register(&rte_virtio_pmd);
 }
 
diff --git a/lib/librte_eal/bsdapp/eal/eal.c b/lib/librte_eal/bsdapp/eal/eal.c
index 508cbc46f..b8152a75c 100644
--- a/lib/librte_eal/bsdapp/eal/eal.c
+++ b/lib/librte_eal/bsdapp/eal/eal.c
@@ -556,9 +556,11 @@ int rte_eal_has_hugepages(void)
 int
 rte_eal_iopl_init(void)
 {
-       static int fd;
+       static int fd = -1;
+
+       if (fd < 0)
+               fd = open("/dev/io", O_RDWR);
 
-       fd = open("/dev/io", O_RDWR);
        if (fd < 0)
                return -1;
        /* keep fd open for iopl */
-- 
2.17.1