arch/mips/kvm/hypcall.c

   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
  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
  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
  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 }