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ffc142d9be
This patch changes the type of nqueued in struct sched_event from int8_t
to int32_t.
In commit d575edf79, the 1 bit flag in struct sched_event has been
changed to int8_t counter to resolve race condition. Signal_event
will decrease the counter and wait_event will increase it and loop if
the counter is greater than 0.
In most cases the uses of signal_event and wait_event are consistent,
except VCPU_EVENT_VIRTUAL_INTERRUPT. In our logic, we signal this event
whenever there is an virtual interrupt, but we wait on it only in
hlt_vmexit_handler, and we reset this event before VMEnter.
In most cases this worked fine. However it has been found that in
certain GPU stress testing scenario, the signaling of this event
happened too frequently to the point where this int8_t counter underflowed
(i.e., hit -128 and then became 127). Then in subsequent
hlt_vmexit_handler, hv waited on this event and stuck there as the
counter was too large.
This patch changes the type from int8_t to int32_t to avoid underflow.
Tracked-On: #7567
Signed-off-by: Yifan Liu <yifan1.liu@intel.com>
Project ACRN Embedded Hypervisor ################################ .. raw:: html <img src="doc/images/ACRN_Logo_PrimaryLockup_COLOR-300x300-1.png" height="175px" align="right"> The open source project ACRN defines a device hypervisor reference stack and an architecture for running multiple software subsystems, managed securely, on a consolidated system by means of a virtual machine manager. It also defines a reference framework implementation for virtual device emulation, called the "ACRN Device Model". The ACRN Hypervisor is a Type 1 reference hypervisor stack, running directly on the bare-metal hardware, and is suitable for a variety of IoT and embedded device solutions. The ACRN hypervisor addresses the gap that currently exists between datacenter hypervisors, and hard partitioning hypervisors. The ACRN hypervisor architecture partitions the system into different functional domains, with carefully selected guest OS sharing optimizations for IoT and embedded devices. .. start_include_here Community Support ***************** The Project ACRN Developer Community includes developers from member organizations and the general community all joining in the development of software within the project. Members contribute and discuss ideas, submit bugs and bug fixes. They also help those in need through the community's forums such as mailing lists and IRC channels. Anyone can join the developer community and the community is always willing to help its members and the User Community to get the most out of Project ACRN. Welcome to the project ACRN community! We're now holding monthly Technical Community Meetings and encourage you to call in and learn more about the project. Meeting information is on the `TCM Meeting page`_ in our `ACRN wiki <https://wiki.projectacrn.org/>`_. .. _TCM Meeting page: https://github.com/projectacrn/acrn-hypervisor/wiki/ACRN-Committee-and-Working-Group-Meetings#technical-community-meetings Resources ********* Here's a quick summary of resources to find your way around the Project ACRN support systems: * **Project ACRN Website**: The https://projectacrn.org website is the central source of information about the project. On this site, you'll find background and current information about the project as well as relevant links to project material. For a quick start, refer to the `ACRN Introduction`_ and `Getting Started Guide`_. * **Source Code in GitHub**: Project ACRN source code is maintained on a public GitHub repository at https://github.com/projectacrn/acrn-hypervisor. You'll find information about getting access to the repository and how to contribute to the project in this `Contribution Guide`_ document. * **Documentation**: Project technical documentation is developed along with the project's code, and can be found at https://projectacrn.github.io. Additional documentation is maintained in the `Project ACRN GitHub wiki`_. * **Issue Reporting and Tracking**: Requirements and Issue tracking is done in the Github issues system: https://github.com/projectacrn/acrn-hypervisor/issues. You can browse through the reported issues and submit issues of your own. * **Reporting a Potential Security Vulnerability**: If you have discovered potential security vulnerability in ACRN, please send an e-mail to acrn-security@lists.projectacrn.org. It is important to include the following details: - The projects and versions affected - Detailed description of the vulnerability - Information on known exploits * **Mailing List**: The `Project ACRN Development mailing list`_ is perhaps the most convenient way to track developer discussions and to ask your own support questions to the project ACRN community. There are also specific `ACRN mailing list subgroups`_ for builds, users, and Technical Steering Committee notes, for example. You can read through the message archives to follow past posts and discussions, a good thing to do to discover more about the project. .. _ACRN Introduction: https://projectacrn.github.io/latest/introduction/ .. _Getting Started Guide: https://projectacrn.github.io/latest/getting-started/ .. _Contribution Guide: https://projectacrn.github.io/latest/contribute.html .. _Project ACRN GitHub wiki: https://github.com/projectacrn/acrn-hypervisor/wiki .. _PGP Key: https://www.intel.com/content/www/us/en/security-center/pgp-public-key.html .. _vulnerability handling guidelines: https://www.intel.com/content/www/us/en/security-center/vulnerability-handling-guidelines.html .. _Project ACRN Development mailing list: https://lists.projectacrn.org/g/acrn-dev .. _ACRN mailing list subgroups: https://lists.projectacrn.org/g/main/subgroups