arch/riscv/kvm/vcpu_sbi_hsm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2021 Western Digital Corporation or its affiliates.
   4  *
   5  * Authors:
   6  *     Atish Patra <atish.patra@wdc.com>
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/err.h>
  11 #include <linux/kvm_host.h>
  12 #include <asm/sbi.h>
  13 #include <asm/kvm_vcpu_sbi.h>
  14
  15 static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu)
  16 {
  17         struct kvm_cpu_context *reset_cntx;
  18         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
  19         struct kvm_vcpu *target_vcpu;
  20         unsigned long target_vcpuid = cp->a0;
  21
  22         target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
  23         if (!target_vcpu)
  24                 return SBI_ERR_INVALID_PARAM;
  25         if (!target_vcpu->arch.power_off)
  26                 return SBI_ERR_ALREADY_AVAILABLE;
  27
  28         reset_cntx = &target_vcpu->arch.guest_reset_context;
  29         /* start address */
  30         reset_cntx->sepc = cp->a1;
  31         /* target vcpu id to start */
  32         reset_cntx->a0 = target_vcpuid;
  33         /* private data passed from kernel */
  34         reset_cntx->a1 = cp->a2;
  35         kvm_make_request(KVM_REQ_VCPU_RESET, target_vcpu);
  36
  37         kvm_riscv_vcpu_power_on(target_vcpu);
  38
  39         return 0;
  40 }
  41
  42 static int kvm_sbi_hsm_vcpu_stop(struct kvm_vcpu *vcpu)
  43 {
  44         if (vcpu->arch.power_off)
  45                 return SBI_ERR_FAILURE;
  46
  47         kvm_riscv_vcpu_power_off(vcpu);
  48
  49         return 0;
  50 }
  51
  52 static int kvm_sbi_hsm_vcpu_get_status(struct kvm_vcpu *vcpu)
  53 {
  54         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
  55         unsigned long target_vcpuid = cp->a0;
  56         struct kvm_vcpu *target_vcpu;
  57
  58         target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
  59         if (!target_vcpu)
  60                 return SBI_ERR_INVALID_PARAM;
  61         if (!target_vcpu->arch.power_off)
  62                 return SBI_HSM_STATE_STARTED;
  63         else if (vcpu->stat.generic.blocking)
  64                 return SBI_HSM_STATE_SUSPENDED;
  65         else
  66                 return SBI_HSM_STATE_STOPPED;
  67 }
  68
  69 static int kvm_sbi_ext_hsm_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
  70                                    struct kvm_vcpu_sbi_return *retdata)
  71 {
  72         int ret = 0;
  73         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
  74         struct kvm *kvm = vcpu->kvm;
  75         unsigned long funcid = cp->a6;
  76
  77         switch (funcid) {
  78         case SBI_EXT_HSM_HART_START:
  79                 mutex_lock(&kvm->lock);
  80                 ret = kvm_sbi_hsm_vcpu_start(vcpu);
  81                 mutex_unlock(&kvm->lock);
  82                 break;
  83         case SBI_EXT_HSM_HART_STOP:
  84                 ret = kvm_sbi_hsm_vcpu_stop(vcpu);
  85                 break;
  86         case SBI_EXT_HSM_HART_STATUS:
  87                 ret = kvm_sbi_hsm_vcpu_get_status(vcpu);
  88                 if (ret >= 0) {
  89                         retdata->out_val = ret;
  90                         retdata->err_val = 0;
  91                 }
  92                 return 0;
  93         case SBI_EXT_HSM_HART_SUSPEND:
  94                 switch (cp->a0) {
  95                 case SBI_HSM_SUSPEND_RET_DEFAULT:
  96                         kvm_riscv_vcpu_wfi(vcpu);
  97                         break;
  98                 case SBI_HSM_SUSPEND_NON_RET_DEFAULT:
  99                         ret = SBI_ERR_NOT_SUPPORTED;
 100                         break;
 101                 default:
 102                         ret = SBI_ERR_INVALID_PARAM;
 103                 }
 104                 break;
 105         default:
 106                 ret = SBI_ERR_NOT_SUPPORTED;
 107         }
 108
 109         retdata->err_val = ret;
 110
 111         return 0;
 112 }
 113
 114 const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm = {
 115         .extid_start = SBI_EXT_HSM,
 116         .extid_end = SBI_EXT_HSM,
 117         .handler = kvm_sbi_ext_hsm_handler,
 118 };