On 01/18/2018 02:21 AM, Erik Skultety wrote:
On Wed, Jan 17, 2018 at 10:46:32AM -0700, Jim Fehlig wrote:
Commit 8708ca01c added virNetDevSwitchdevFeature() to check if a network
device has Switchdev capabilities. virNetDevSwitchdevFeature() attempts
to retrieve the PCI device associated with the network device, ignoring
non-PCI devices. It does so via the following call chain
virNetDevSwitchdevFeature()->virNetDevGetPCIDevice()->
virPCIGetDeviceAddressFromSysfsLink()
For non-PCI network devices (qeth, Xen vif, etc),
virPCIGetDeviceAddressFromSysfsLink() will report an error when
virPCIDeviceAddressParse() fails. virPCIDeviceAddressParse() also
logs an error. After commit 8708ca01c there are now two errors reported
for each non-PCI network device even though the errors are harmless.
To avoid the errors, introduce virNetDevIsPCIDevice() and use it in
virNetDevGetPCIDevice() before attempting to retrieve the associated
PCI device. virNetDevIsPCIDevice() uses the 'subsystem' property of the
device to determine if it is PCI. See the sysfs rules in kernel
documentation for more details
https://www.kernel.org/doc/html/latest/admin-guide/sysfs-rules.html
---
V2: https://www.redhat.com/archives/libvir-list/2018-January/msg00233.html
Changes in V3:
Implement checking if netdev is PCI in virnetdev.c instead of virpci.c
Addressed other comments from eskultet
src/util/virnetdev.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c
index eb2d119bf..baf4a71fe 100644
--- a/src/util/virnetdev.c
+++ b/src/util/virnetdev.c
@@ -22,6 +22,7 @@
#include <config.h>
+#include "dirname.h"
#include "virnetdev.h"
#include "virnetlink.h"
#include "virmacaddr.h"
@@ -1147,6 +1148,48 @@ virNetDevSysfsDeviceFile(char **pf_sysfs_device_link, const char *ifname,
return 0;
}
+/**
+ * Determine if the device path specified in devpath is a PCI Device
+ * by resolving the 'subsystem'-link in devpath and looking for
+ * 'pci' in the last component. For more information see the rules
+ * for accessing sysfs in the kernel docs
+ *
+ * https://www.kernel.org/doc/html/latest/admin-guide/sysfs-rules.html
+ *
+ * Returns true if devpath's susbsystem is pci, false otherwise.
+ */
+static bool
+virNetDevIsPCIDevice(const char *devpath)
+{
+ char *subsys_link = NULL;
+ char *abs_path = NULL;
+ char *subsys = NULL;
+ bool ret = false;
+
+ if (virAsprintf(&subsys_link, "%s/subsystem", devpath) < 0)
+ return false;
+
+ if (!virFileExists(subsys_link))
+ goto cleanup;
+
+ if (virFileIsLink(subsys_link) != 1)
+ goto cleanup;
+
You don't really need ^this check, do you? Once the path exists,
virFileResolveLink is going to handle it gracefully.
I removed the check.
Reviewed-by: Erik Skultety <eskultet@xxxxxxxxxx> (but I'd wait with pushing
until after the release)
Pushed now that the release is out. And agreed waiting until after the release
was best since there are other callers of virNetDevGetPCIDevice() that could be
affected - although I did check those and they seem fine.
Regards,
Jim
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