CTR_EL0 can often be used in userspace, and it would be nice if KVM didn't have to emulate it unnecessarily. While it isn't possible to trap the cache configuration registers independently from CTR_EL0 in the base ARMv8.0 architecture, FEAT_EVT allows these cache configuration registers (CCSIDR_EL1, CCSIDR2_EL1, CLIDR_EL1 and CSSELR_EL1) to be trapped independently by setting HCR_EL2.TID4. Switch to using TID4 instead of TID2 in the cases where FEAT_EVT is available *and* that KVM doesn't need to sanitise CTR_EL0 to paper over mismatched cache configurations. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230515170016.965378-1-maz@kernel.org 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.
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