KVM: arm64: Inject UNDEF when accessing MTE sysregs with MTE disabled

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When MTE hardware is present but disabled via software (`arm64.nomte` or
`CONFIG_ARM64_MTE=n`), the kernel clears `HCR_EL2.ATA` and sets
`HCR_EL2.TID5`, to prevent the use of MTE instructions.

Additionally, accesses to certain MTE system registers trap to EL2 with
exception class ESR_ELx_EC_SYS64. To emulate hardware without MTE (where
such accesses would cause an Undefined Instruction exception), inject
UNDEF into the host.

Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260122112218.531948-4-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

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Fuad Tabba 2026-01-22 11:22:17 +00:00 • committed by Marc Zyngier

parent f35abcbb8a

commit 5ee8ad69da

1 changed files with 67 additions and 0 deletions

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arch/arm64/kvm/hyp/nvhe/hyp-main.c

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