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commit 812de04661c4daa7ac385c0dfd62594540538034 upstream. With KVM_CAP_S390_USER_SIGP, there are only five Signal Processor orders (CONDITIONAL EMERGENCY SIGNAL, EMERGENCY SIGNAL, EXTERNAL CALL, SENSE, and SENSE RUNNING STATUS) which are intended for frequent use and thus are processed in-kernel. The remainder are sent to userspace with the KVM_CAP_S390_USER_SIGP capability. Of those, three orders (RESTART, STOP, and STOP AND STORE STATUS) have the potential to inject work back into the kernel, and thus are asynchronous. Let's look for those pending IRQs when processing one of the in-kernel SIGP orders, and return BUSY (CC2) if one is in process. This is in agreement with the Principles of Operation, which states that only one order can be "active" on a CPU at a time. Cc: stable@vger.kernel.org Suggested-by: David Hildenbrand <david@redhat.com> Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com> Acked-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20211213210550.856213-2-farman@linux.ibm.com [borntraeger@linux.ibm.com: add stable tag] Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.