LoongArch: KVM: Add sign extension with kernel IOCSR read emulation

Function kvm_complete_iocsr_read() is to add sign extension with IOCSR
read emulation, it is used in user space IOCSR read completion now. Also
it should be used in kernel IOCSR read emulation.

Signed-off-by: Bibo Mao <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>

Author: bibo-mao

arch/loongarch/kvm/exit.c

@@ -218,16 +218,16 @@ int kvm_emu_iocsr(larch_inst inst, struct kvm_run *run, struct kvm_vcpu *vcpu)
 		}
 		trace_kvm_iocsr(KVM_TRACE_IOCSR_WRITE, run->iocsr_io.len, addr, val);
 	} else {
+		vcpu->arch.io_gpr = rd; /* Set register id for iocsr read completion */
 		idx = srcu_read_lock(&vcpu->kvm->srcu);
-		ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr, run->iocsr_io.len, val);
+		ret = kvm_io_bus_read(vcpu, KVM_IOCSR_BUS, addr,
+				      run->iocsr_io.len, run->iocsr_io.data);
 		srcu_read_unlock(&vcpu->kvm->srcu, idx);
-		if (ret == 0)
+		if (ret == 0) {
+			kvm_complete_iocsr_read(vcpu, run);
 			ret = EMULATE_DONE;
-		else {
+		} else
 			ret = EMULATE_DO_IOCSR;
-			/* Save register id for iocsr read completion */
-			vcpu->arch.io_gpr = rd;
-		}
 		trace_kvm_iocsr(KVM_TRACE_IOCSR_READ, run->iocsr_io.len, addr, NULL);
 	}