mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-07-08 18:13:59 +02:00
Bibo Mao
708d585480
commit 5a873d77ba upstream.
When timer interrupt arrives in guest kernel, guest kernel clears the
timer interrupt and program timer with the next incoming event.
During this stage, timer tick is -1 and timer interrupt status is
disabled in ESTAT register. KVM hypervisor need write zero with timer
tick register and wait timer interrupt injection from HW side, and
then clear timer interrupt.
So there is 2 cycle delay in KVM hypervisor to emulate such scenery,
and the delay is unnecessary if there is no need to clear the timer
interrupt.
Here move 2 cycle delay into timer clear scenery and add timer ESTAT
checking after delay, and set max timer expire value if timer interrupt
does not arrive still.
Cc: stable@vger.kernel.org
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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 reStructuredText 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.