[libvirt] [PATCH 1/2] util:mdev: Improve the error msg on non-existent mdev prior to VM start

Erik Skultety eskultet at redhat.com
Fri Mar 16 10:50:01 UTC 2018


What one currently gets is:
failed to read '/sys/bus/mdev/devices/<UUID>/mdev_type/device_api': No
such file or directory

This indicates that something is missing within the device's sysfs tree
which likely might be not be the case here because the device simply
doesn't exist yet. So, when creating our internal mdev obj, let's check
whether the device exists first prior to trying to verify the
user-provided model within domain XML.

Signed-off-by: Erik Skultety <eskultet at redhat.com>
---
 src/util/virmdev.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/util/virmdev.c b/src/util/virmdev.c
index e4816cf20..2e3769aa6 100644
--- a/src/util/virmdev.c
+++ b/src/util/virmdev.c
@@ -150,13 +150,22 @@ virMediatedDeviceNew(const char *uuidstr, virMediatedDeviceModelType model)
 {
     virMediatedDevicePtr ret = NULL;
     virMediatedDevicePtr dev = NULL;
+    char *sysfspath = NULL;
+
+    if (!(sysfspath = virMediatedDeviceGetSysfsPath(uuidstr)))
+        goto cleanup;
+
+    if (!virFileExists(sysfspath)) {
+        virReportSystemError(errno, _("failed to read device '%s'"),
+                             sysfspath);
+        goto cleanup;
+    }
 
     if (VIR_ALLOC(dev) < 0)
-        return NULL;
-
-    if (!(dev->path = virMediatedDeviceGetSysfsPath(uuidstr)))
         goto cleanup;
 
+    VIR_STEAL_PTR(dev->path, sysfspath);
+
     /* Check whether the user-provided model corresponds with the actually
      * supported mediated device's API.
      */
@@ -167,6 +176,7 @@ virMediatedDeviceNew(const char *uuidstr, virMediatedDeviceModelType model)
     VIR_STEAL_PTR(ret, dev);
 
  cleanup:
+    VIR_FREE(sysfspath);
     virMediatedDeviceFree(dev);
     return ret;
 }
-- 
2.13.6




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