------- Comment From heinz-werner_se...@de.ibm.com 2019-02-05 02:50 EDT------- IBM Bugzilla status -> closed, Fix Released for all Distros
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1805414 Title: [Ubuntu] kernel: zcrypt: reinit ap queue state machine Status in Ubuntu on IBM z Systems: Fix Released Status in linux package in Ubuntu: Fix Released Status in linux source package in Bionic: Fix Released Status in linux source package in Cosmic: Fix Released Status in linux source package in Disco: Fix Released Bug description: == SRU Justification == The vfio device driver when receiving an ap queue device does additional resets thereby removing the registration for interrupts for the ap device done by the ap bus core code. So when later the vfio driver releases the device and one of the default zcrypt drivers takes care of the device the interrupt registration needs to get renewed. The current code does no renew and result is that requests send into such a queue will never see a reply processed - the application hangs. This commit has also been cc'd to upstream stable. == Fix == 104f708fd ("s390/zcrypt: reinit ap queue state machine during device probe") == Regression Potential == Low. Limited to s390. == Original Bug Description == Description: kernel: zcrypt: reinit ap queue state machine Symptom: Zcrypt ap queue device not operational at host level after a kvm guest used it. Problem: The vfio device driver when receiving an ap queue device does additional resets thereby removing the registration for interrupts for the ap device done by the ap bus core code. So when later the vfio driver releases the device and one of the default zcrypt drivers takes care of the device the interrupt registration needs to get renewed. The current code does no renew and result is that requests send into such a queue will never see a reply processed - the application hangs. Solution: This patch adds a function which resets the aq queue state machine for the ap queue device and triggers the walk through the initial states (which are reset and registration for interrupts). This function is now called before the driver's probe function is invoked. When the association between driver and device is released, the driver's remove function is called. The current implementation calls a ap queue function ap_queue_remove(). This invokation has been moved to the ap bus function to make the probe / remove pair for ap bus and drivers more symmetric. Reproduction: Set up an kvm guest to use one or more ap queues in pass-through mode. Start the guest. Stop the guest. Reassign the ap resources back to the host system. Run an application which uses exactly this ap resources. Without the fix, the application hangs; with the fix the application should run fine. Upstream commit(s): 104f708fd1241b22f808bdf066ab67dc5a051de5 Available on kernel.org To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1805414/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
