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>

Author: zcxGGmu

arch/riscv/kvm/vcpu_exit.c

@@ -187,6 +187,7 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 	case EXC_STORE_MISALIGNED:
 	case EXC_LOAD_ACCESS:
 	case EXC_STORE_ACCESS:
+	case EXC_INST_ACCESS:
 		if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) {
 			kvm_riscv_vcpu_trap_redirect(vcpu, trap);
 			ret = 1;