[libvirt] [PATCH v2 1/2] util: mdev: Improve the error msg on non-existent mdev prior to VM start

Erik Skultety posted 2 patches 7 years, 10 months ago
[libvirt] [PATCH v2 1/2] util: mdev: Improve the error msg on non-existent mdev prior to VM start
Posted by Erik Skultety 7 years, 10 months ago
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@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..27541cf34 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)) {
+        virReportError(VIR_ERR_DEVICE_MISSING,
+                       _("mediated device '%s' not found"), uuidstr);
+        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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Re: [libvirt] [PATCH v2 1/2] util: mdev: Improve the error msg on non-existent mdev prior to VM start
Posted by Peter Krempa 7 years, 10 months ago
On Fri, Mar 16, 2018 at 13:37:53 +0100, Erik Skultety wrote:
> 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@redhat.com>
> ---
>  src/util/virmdev.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)

ACK
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