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934bf871f0
To date the VHE code has aggressively reloaded the stage-2 MMU context on every guest entry, despite the fact that this isn't necessary. This was probably done for consistency with the nVHE code, which needs to switch in/out the stage-2 MMU context as both the host and guest run at EL1. Hoist __load_stage2() into kvm_vcpu_load_vhe(), thus avoiding a reload on every guest entry/exit. This is likely to be beneficial to systems with one of the speculative AT errata, as there is now one fewer context synchronization event on the guest entry path. Additionally, it is possible that implementations have hitched correctness mitigations on writes to VTTBR_EL2, which are now elided on guest re-entry. Note that __tlb_switch_to_guest() is deliberately left untouched as it can be called outside the context of a running vCPU. Link: https://lore.kernel.org/r/20231018233212.2888027-6-oliver.upton@linux.dev 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.