Directed interrupt for multilevel virtualization with interrupt table

Patent metadata

Field	Value
Publication number	US-11269794-B2
Application number	US-202016789556-A
Country	US
Kind code	B2
Filing date	Feb 13, 2020
Priority date	Feb 14, 2019
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

An interrupt signal is provided to a first guest operating system. A bus attachment device receives an interrupt signal from a bus connected module with an interrupt target ID identifying a processor assigned for use by the guest operating system as a target processor for handling the interrupt signal. The bus attachment device translates the received interrupt target ID to a logical processor ID of the target processor using an interrupt table entry stored in a memory section assigned to a second guest operating system hosting the first operating system and forwards the interrupt signal to the target processor for handling. The logical processor ID of the target processor is used to address the target processor directly.

First claim

What is claimed is:

1. A computer program product for providing an interrupt signal to a first guest operating system executed using one or more processors of a plurality of processors of a computer system assigned for usage by the first guest operating system, the computer program product comprising:
at least one computer readable storage medium readable by at least one processing circuit and storing instructions for performing a method comprising:
receiving, by a bus attachment device from one bus connected module of a plurality of bus connected modules operationally coupled to the plurality of processors via the bus attachment device, an interrupt signal with an interrupt target ID, the interrupt target ID identifying one processor of the plurality of processors assigned for usage by the first guest operating system as a target processor to handle the interrupt signal, the first guest operating system implemented using a second guest operating system as a host hosting the first guest operating system;
retrieving, by the bus attachment device, a copy of an interrupt table entry assigned to the interrupt target ID from an interrupt table stored in a first memory section of a memory operationally connected with the bus attachment device, the first memory section being assigned to the second guest operating system, and the copy of the interrupt table entry comprising a mapping of the interrupt target ID to a logical processor ID;
translating, by the bus attachment device, the interrupt target ID to the logical processor ID using the copy of the interrupt table entry; and
forwarding, by the bus attachment device, the interrupt signal to the target processor to handle, the forwarding using the logical processor ID resulting from the translating to address the target processor directly.

2. The computer program product of claim 1 , wherein the memory further comprises in a second memory section assigned to the first guest operating system a directed interrupt summary vector with a directed interrupt summary indicator per interrupt target ID, each directed interrupt summary indicator being assigned to a respective interrupt target ID to indicate whether there is a respective interrupt signal addressed to the respective interrupt target ID to be handled, and wherein the memory comprises in the first memory section a forwarding vector comprising a first set of forwarding vector entries, the first set of forwarding vector entries comprising for each directed interrupt summary indicator of the directed interrupt summary vector a forwarding vector entry assigned to a respective directed interrupt summary indicator, each forwarding vector entry indicating whether the respective directed interrupt summary indicator to which it is assigned is to be updated in order to indicate for the first guest operating system that there is the respective interrupt signal addressed to the respective interrupt target ID to be handled, and wherein the method further comprises:
checking, by the bus attachment device, whether the target processor is scheduled for usage by the first guest operating system; and
performing the translating and the forwarding, based on the target processor being scheduled for usage by the first guest operating system, else forwarding, by the bus attachment device, the interrupt signal to the first guest operating system using broadcasting, the broadcasting comprising selecting by the bus attachment device a selected forwarding vector entry of the first set of forwarding vector entries which is assigned to the interrupt target ID and updating the selected forwarding vector entry such that it indicates that the respective directed interrupt summary indicator to which it is assigned is to be updated in order to indicate for the first guest operating system that there is the interrupt signal addressed to the interrupt target ID to be handled.

3. The computer program product of claim 2 , wherein the second memory section of the memory further comprises an interrupt summary vector with an interrupt summary indicator per bus connected module to indicate whether there is the respective interrupt signal issued by the respective bus connected module to be handled, and wherein the forwarding vector further comprises a second set of forwarding vector entries, the second set of forwarding vector entries comprising a second forwarding vector entry assigned to a respective interrupt summary indicator, the second forwarding vector entry to indicate whether the respective interrupt summary indicator to which it is assigned is to be updated in order to indicate for the first guest operating system that there is the respective interrupt signal issued by the respective bus connected module to be handled, and wherein the method further comprises:
receiving, by the bus attachment device, another interrupt signal from a second bus connected module with another interrupt target ID, the other interrupt target ID identifying a second target processor for usage by the first guest operating system to handle the other interrupt signal;
checking, by the bus attachment device, whether the second target processor is scheduled for usage by the first guest operating system;
translating, by the bus attachment device based on the second target processor being scheduled for usage by the first guest operating system, the other interrupt target ID to another logical processor ID and forwarding the other interrupt signal to the second target processor to handle using the other logical processor ID resulting from the translating to address the second target processor directly; and
forwarding by the bus attachment device based on the second target processor not being scheduled, the second interrupt signal to the first guest operating system using broadcasting, the broadcasting comprising selecting, by the bus attachment device, a selected second forwarding vector entry of the second set of forwarding vector entries which is assigned to the other interrupt target ID and updating the selected second forwarding vector entry such that it indicates that the respective interrupt summary indicator to which it is assigned is to be updated in order to indicate for the first guest operating system that there is the second interrupt signal issued by the second bus connected module to be handled.

4. The computer program product of claim 2 , wherein the first memory section further comprises a guest interrupt table, the guest interrupt table comprising a first set of guest interrupt table entries, the first set of guest interrupt table entries comprising a directed interrupt summary address indicator for each of the directed interrupt summary indicators of the directed interrupt summary vector with a respective directed interrupt summary address indicator indicating a memory address of the respective directed interrupt summary indicator in the second memory section, and wherein assignments of forwarding vector entries of the first set of forwarding vector entries are implemented using the guest interrupt table with each forwarding vector entry of the first set of forwarding vector entries being assigned a guest interrupt table entry of the first set of guest interrupt table entries, and wherein the directed interrupt summary address indicator of the respective guest interrupt table entry indicates the memory address of the respective directed interrupt summary indicator to which a respective forwarding vector entry is assigned.

5. The computer program product of claim 2 , wherein the copy of the interrupt table entry further comprises a running indicator to indicate whether the target processor identified by the interrupt target ID is scheduled for usage by the first guest operating system, and wherein the method further comprises using, by the bus attachment device, the running indi

Assignees

• IBM

Inventors

• Raisch Christoph
• Kraemer Marco
• Schmidt Donald William
• Nerz Bernd
• Driever Peter Dana

Classifications

• G06F13/24 Primary

  using interrupt (G06F13/32 takes precedence) · CPC title

• G06F9/5077

  Logical partitioning of resources; Management or configuration of virtualized resources (specific details on emulation or internal functioning of virtual machines G06F9/455) · CPC title

• G06F12/1081

  for peripheral access to main memory, e.g. direct memory access [DMA] · CPC title

• G06F9/48

  Program initiating; Program switching, e.g. by interrupt · CPC title

• G06F9/45533 Primary

  Hypervisors; Virtual machine monitors · CPC title