RISC-V: KVM: Redirect instruction access fault trap to guest

RISC-V: KVM: Redirect instruction access fault trap to guest

The M-mode redirects an unhandled instruction access
fault trap back to S-mode when not delegating it to
VS-mode(hedeleg). However, KVM running in HS-mode
terminates the VS-mode software when back from M-mode.

The KVM should redirect the trap back to VS-mode, and
let VS-mode trap handler decide the next step.

Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20241224-kvm_guest_stat-v2-1-08a77ac36b02@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>