From 3d1121ecc9a2fa0e6be2df92f04990ec6d44be56 Mon Sep 17 00:00:00 2001

Message-Id: <3d1121ecc9a2fa0e6be2df92f04990ec6d44be56@dist-git>

From: Laine Stump <laine@laine.org>

Date: Wed, 20 Sep 2017 07:35:18 -0400

Subject: [PATCH] util: virPCIGetNetName(): use first netdev name when

 phys_port_id isn't matched

The mlx4 (Mellanox) netdev driver implements the sysfs phys_port_id

file for both VFs and PFs, so you can find the VF netdev plugged into

the same physical port as any given PF netdev by comparing the

contents of phys_port_id of the respective netdevs. That's what

libvirt does when attempting to find the PF netdev for a given VF

netdev (or vice versa).

Most other netdev's drivers don't implement phys_port_id, so the file

is visible in sysfs directory listing, but attempts to read it result

in ENOTSUPP. In these cases, libvirt is unable to read phys_port_id of

either the PF or the VF, so it just returns the first entry in the

PF/VF's list of netdevs.

But we've found that the i40e driver is in between those two

situations - it implements phys_port_id for PF netdevs, but doesn't

implement it for VF netdevs. So libvirt would successfully read the

phys_port_id of the PF netdev, then try to find a VF netdev with

matching phys_port_id, but would fail because phys_port_id is NULL for

all VFs. This would result in a message like the following:

   Could not find network device with phys_port_id '3cfdfe9edc39'

   under PCI device at /sys/class/net/ens4f1/device/virtfn0

To solve this problem in a way that won't break functionality for

anyone else, this patch saves the first netdev name we find for the

device, and returns that if we fail to find a netdev with the desired

phys_port_id.

Resolves: https://bugzilla.redhat.com/1489263

(cherry picked from commit 747116e0b904a4bc3c438c1fe6badd9961504814)

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 src/util/virpci.c | 31 +++++++++++++++++++++++++++----

 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/src/util/virpci.c b/src/util/virpci.c

index ea8fc228fc..54e65feab0 100644

--- a/src/util/virpci.c

+++ b/src/util/virpci.c

@@ -2878,6 +2878,7 @@ virPCIGetNetName(const char *device_link_sysfs_path,

     int ret = -1;

     DIR *dir = NULL;

     struct dirent *entry = NULL;

+    char *firstEntryName = NULL;

     char *thisPhysPortID = NULL;

     size_t i = 0;

@@ -2904,6 +2905,16 @@ virPCIGetNetName(const char *device_link_sysfs_path,

             /* if this one doesn't match, keep looking */

             if (STRNEQ_NULLABLE(physPortID, thisPhysPortID)) {

                 VIR_FREE(thisPhysPortID);

+                /* save the first entry we find to use as a failsafe

+                 * in case we don't match the phys_port_id. This is

+                 * needed because some NIC drivers (e.g. i40e)

+                 * implement phys_port_id for PFs, but not for VFs

+                 */

+                if (!firstEntryName &&

+                    VIR_STRDUP(firstEntryName, entry->d_name) < 0) {

+                    goto cleanup;

+                }

+

                 continue;

             }

         } else {

@@ -2920,10 +2931,21 @@ virPCIGetNetName(const char *device_link_sysfs_path,

     if (ret < 0) {

         if (physPortID) {

-            virReportError(VIR_ERR_INTERNAL_ERROR,

-                           _("Could not find network device with "

-                             "phys_port_id '%s' under PCI device at %s"),

-                           physPortID, device_link_sysfs_path);

+            if (firstEntryName) {

+                /* we didn't match the provided phys_port_id, but this

+                 * is probably because phys_port_id isn't implemented

+                 * for this NIC driver, so just return the first

+                 * (probably only) netname we found.

+                 */

+                *netname = firstEntryName;

+                firstEntryName = NULL;

+                ret = 0;

+            } else {

+                virReportError(VIR_ERR_INTERNAL_ERROR,

+                               _("Could not find network device with "

+                                 "phys_port_id '%s' under PCI device at %s"),

+                               physPortID, device_link_sysfs_path);

+            }

         } else {

             ret = 0; /* no netdev at the given index is *not* an error */

         }

@@ -2932,6 +2954,7 @@ virPCIGetNetName(const char *device_link_sysfs_path,

     VIR_DIR_CLOSE(dir);

     VIR_FREE(pcidev_sysfs_net_path);

     VIR_FREE(thisPhysPortID);

+    VIR_FREE(firstEntryName);

     return ret;

 }

-- 

2.14.2