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