278583055a
Injecting an exception into a guest with non-VHE is risky business.
Instead of writing in the shadow register for the switch code to
restore it, we override the CPU register instead. Which gets
overriden a few instructions later by said restore code.
The result is that although the guest correctly gets the exception,
it will return to the original context in some random state,
depending on what was there the first place... Boo.
Fix the issue by writing to the shadow register. The original code
is absolutely fine on VHE, as the state is already loaded, and writing
to the shadow register in that case would actually be a bug.
Fixes: bb666c472ca2 ("KVM: arm64: Inject AArch64 exceptions from HYP")
Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20220121184207.423426-1-maz@kernel.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 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.