LXR linux/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
  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