mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-29 17:35:36 -04:00
56fc39f5a3
"Interrupt handle revoked" is an event that happens when the driver is running on a guest kernel and the VM is migrated to a new machine. The device will trigger an interrupt that signals to the guest driver that the interrupt handles need to be replaced. The misc irq thread function calls a helper function to handle the event. The function uses the WQ percpu_ref to quiesce the kernel submissions. It then replaces the interrupt handles by requesting interrupt handle command for each I/O MSIX vector. Once the handle is updated, the driver will unblock the submission path to allow new submissions. The submitter will attempt to acquire a percpu_ref before submission. When the request fails, it will wait on the wq_resurrect 'completion'. The driver does anticipate the possibility of descriptors being submitted before the WQ percpu_ref is killed. If a descriptor has already been submitted, it will return with incorrect interrupt handle status. The descriptor will be re-submitted with the new interrupt handle on the completion path. For descriptors with incorrect interrupt handles, completion interrupt won't be triggered. At the completion of the interrupt handle refresh, the handling function will call idxd_int_handle_refresh_drain() to issue drain descriptors to each of the wq with associated interrupt handle. The drain descriptor will have interrupt request set but without completion record. This will ensure all descriptors with incorrect interrupt completion handle get drained and a completion interrupt is triggered for the guest driver to process them. Reviewed-by: Kevin Tian <kevin.tian@intel.com> Co-Developed-by: Sanjay Kumar <sanjay.k.kumar@intel.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/163528420189.3925689.18212568593220415551.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.