6479450f72
1. In current implementation, every VLPI will temporarily be mapped to
the first CPU in system (normally CPU0) and then moved to the real
scheduled CPU later.
2. So there is a time window and a VLPI may be sent to CPU0 instead of
the real scheduled vCPU, in a multi-CPU virtual machine.
3. However, CPU0 may have not been scheduled as a virtual CPU after
system boots up, so the value of its GICR_VPROPBASER is unknown at
that moment.
4. If the INTID of VLPI is larger than 2^(GICR_VPROPBASER.IDbits+1),
while IDbits is also in unknown state, GIC will behave as if the VLPI
is out of range and simply drop it, which results in interrupt missing
in Guest.
As no code will clear GICR_VPROPBASER at runtime, we can safely
initialize the IDbits field at boot time for each CPU to get rid of
this issue.
We also clear Valid bit of GICR_VPENDBASER in case any ancient
programming gets left in and causes memory corrupting. A new function
its_clear_vpend_valid() is added to reuse the code in
its_vpe_deschedule().
Fixes: e643d8034036 ("irqchip/gic-v3-its: Add VPE scheduling")
Signed-off-by: Heyi Guo <guoheyi@huawei.com>
Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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.