arm64/kvm: hide ptrauth from guests

In subsequent patches we're going to expose ptrauth to the host kernel
and userspace, but things are a bit trickier for guest kernels. For the
time being, let's hide ptrauth from KVM guests.

Regardless of how well-behaved the guest kernel is, guest userspace
could attempt to use ptrauth instructions, triggering a trap to EL2,
resulting in noise from kvm_handle_unknown_ec(). So let's write up a
handler for the PAC trap, which silently injects an UNDEF into the
guest, as if the feature were really missing.

Reviewed-by: Richard Henderson <[email protected]>
Signed-off-by: Mark Rutland <[email protected]>
Signed-off-by: Kristina Martsenko <[email protected]>
Reviewed-by: Andrew Jones <[email protected]>
Reviewed-by: Christoffer Dall <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: [email protected]
Signed-off-by: Will Deacon <[email protected]>

0 files changed, 0 insertions, 0 deletions