1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * KVM/MIPS: Hypercall handling.
7 *
8 * Copyright (C) 2015  Imagination Technologies Ltd.
9 */
10
11#include <linux/kernel.h>
12#include <linux/kvm_host.h>
13#include <linux/kvm_para.h>
14
15#define MAX_HYPCALL_ARGS	4
16
17enum emulation_result kvm_mips_emul_hypcall(struct kvm_vcpu *vcpu,
18					    union mips_instruction inst)
19{
20	unsigned int code = (inst.co_format.code >> 5) & 0x3ff;
21
22	kvm_debug("[%#lx] HYPCALL %#03x\n", vcpu->arch.pc, code);
23
24	switch (code) {
25	case 0:
26		return EMULATE_HYPERCALL;
27	default:
28		return EMULATE_FAIL;
29	};
30}
31
32static int kvm_mips_hypercall(struct kvm_vcpu *vcpu, unsigned long num,
33			      const unsigned long *args, unsigned long *hret)
34{
35	/* Report unimplemented hypercall to guest */
36	*hret = -KVM_ENOSYS;
37	return RESUME_GUEST;
38}
39
40int kvm_mips_handle_hypcall(struct kvm_vcpu *vcpu)
41{
42	unsigned long num, args[MAX_HYPCALL_ARGS];
43
44	/* read hypcall number and arguments */
45	num = vcpu->arch.gprs[2];	/* v0 */
46	args[0] = vcpu->arch.gprs[4];	/* a0 */
47	args[1] = vcpu->arch.gprs[5];	/* a1 */
48	args[2] = vcpu->arch.gprs[6];	/* a2 */
49	args[3] = vcpu->arch.gprs[7];	/* a3 */
50
51	return kvm_mips_hypercall(vcpu, num,
52				  args, &vcpu->arch.gprs[2] /* v0 */);
53}
54