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, hret: &vcpu->arch.gprs[2] /* v0 */);
53}
54

source code of linux/arch/mips/kvm/hypcall.c