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
kvm_mips_emul_hypcall(struct kvm_vcpu * vcpu,union mips_instruction inst)17 enum 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
kvm_mips_hypercall(struct kvm_vcpu * vcpu,unsigned long num,const unsigned long * args,unsigned long * hret)32 static 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
kvm_mips_handle_hypcall(struct kvm_vcpu * vcpu)40 int 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