For a given vfio-ap mdev, determine whether or not the device will
need dynamic config operations. This boils down to whether or not
the device is currently active + whether or not the kernel is
detected to support dynamic config operations (via the
'ap_config' sysfs attribute).
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
If many invocations of mdevctl occur simultaneously (as can happen with
libvirt) then waiting for 5-60 seconds per lock retry is simply too long.
Anticipating this possibility, retry more frequently but also attempt
significantly more retries than before.
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Marc Hartmayer <marc@linux.ibm.com>
Tested-by: Marc Hartmayer <marc@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Since mdevctl commit acf78c1ff6c9 it is now possible for the
get-attributes event to occur between a pre-define and post-define.
This is done in order to obtain the active attributes for the device
before writing them to the config file, and implies that the
get-attributes cannot re-obtain the file lock. For other cases
where mdevctl calls get-attributes, the file lock is not already
held and must be obtained by ap-check before reading attributes from
active devices.
To solve this, let's use the knowledge that mdevctl is a single-threaded
tool and add a test to detect this scenario. If the file lock is
already held by the parent during a get-attributes, don't attempt to
re-acquire it.
Reported-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
