c7dfb2591b
A CPU will not show up in virtualized environment which includes an Enclave. The VM splits its resources into a primary VM and a Enclave VM. While the Enclave is active, the hypervisor will ignore all requests to bring up a CPU and this CPU will remain in CPU_UP_PREPARE state. The kernel will wait up to ten seconds for CPU to show up (do_boot_cpu()) and then rollback the hotplug state back to CPUHP_OFFLINE leaving the CPU state in CPU_UP_PREPARE. The CPU state is set back to CPUHP_TEARDOWN_CPU during the CPU_POST_DEAD stage. After the Enclave VM terminates, the primary VM can bring up the CPU again. Allow to bring up the CPU if it is in the CPU_UP_PREPARE state. [bigeasy: Rewrite commit description.] Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Dongli Zhang <dongli.zhang@oracle.com> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Reviewed-by: Henry Wang <Henry.Wang@arm.com> Link: https://lore.kernel.org/r/20220209080214.1439408-3-bigeasy@linutronix.de
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.