[PATCH V3] arm64: Disable EL2 traps for BRBE instructions executed in EL1

[Will Deacon]

On Tue, May 16, 2023 at 02:00:15PM +0530, Anshuman Khandual wrote:
> This disables EL2 traps for BRBE instructions executed in EL1. This would
> enable BRBE to be configured and used successfully in the guest kernel.
> While here, this updates Documentation/arm64/booting.rst as well.

Is it safe to give the guest access to BRBE if the hypervisor doesn't
switch the state? I'm assuming the architecture defaults to "trap" for a
reason and disabling the trap alone isn't sufficient.

If it _is_ safe, please can you explain that in the commit message? If not,
then this should be at the end of the series adding hypervisor support.

Will