mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-01-16 05:10:07 -05:00
2de451a329
An Armv8.8 FEAT_MOPS main or epilogue instruction will take an exception if executed on a CPU with a different MOPS implementation option (A or B) than the CPU where the preceding prologue instruction ran. In this case the OS exception handler is expected to reset the registers and restart execution from the prologue instruction. A KVM guest may use the instructions at EL1 at times when the guest is not able to handle the exception, expecting that the instructions will only run on one CPU (e.g. when running UEFI boot services in the guest). As KVM may reschedule the guest between different types of CPUs at any time (on an asymmetric system), it needs to also handle the resulting exception itself in case the guest is not able to. A similar situation will also occur in the future when live migrating a guest from one type of CPU to another. Add handling for the MOPS exception to KVM. The handling can be shared with the EL0 exception handler, as the logic and register layouts are the same. The exception can be handled right after exiting a guest, which avoids the cost of returning to the host exit handler. Similarly to the EL0 exception handler, in case the main or epilogue instruction is being single stepped, it makes sense to finish the step before executing the prologue instruction, so advance the single step state machine. Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230922112508.1774352-2-kristina.martsenko@arm.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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.