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/csr.h>
  13 #include <asm/sbi.h>
  14 #include <asm/kvm_vcpu_sbi.h>
  15
  16 static int kvm_sbi_hsm_vcpu_start(struct kvm_vcpu *vcpu)
  17 {
  18         struct kvm_cpu_context *reset_cntx;
  19         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
  20         struct kvm_vcpu *target_vcpu;
  21         unsigned long target_vcpuid = cp->a0;
  22
  23         target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
  24         if (!target_vcpu)
  25                 return -EINVAL;
  26         if (!target_vcpu->arch.power_off)
  27                 return -EALREADY;
  28
  29         reset_cntx = &target_vcpu->arch.guest_reset_context;
  30         /* start address */
  31         reset_cntx->sepc = cp->a1;
  32         /* target vcpu id to start */
  33         reset_cntx->a0 = target_vcpuid;
  34         /* private data passed from kernel */
  35         reset_cntx->a1 = cp->a2;
  36         kvm_make_request(KVM_REQ_VCPU_RESET, target_vcpu);
  37
  38         kvm_riscv_vcpu_power_on(target_vcpu);
  39
  40         return 0;
  41 }
  42
  43 static int kvm_sbi_hsm_vcpu_stop(struct kvm_vcpu *vcpu)
  44 {
  45         if (vcpu->arch.power_off)
  46                 return -EINVAL;
  47
  48         kvm_riscv_vcpu_power_off(vcpu);
  49
  50         return 0;
  51 }
  52
  53 static int kvm_sbi_hsm_vcpu_get_status(struct kvm_vcpu *vcpu)
  54 {
  55         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
  56         unsigned long target_vcpuid = cp->a0;
  57         struct kvm_vcpu *target_vcpu;
  58
  59         target_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, target_vcpuid);
  60         if (!target_vcpu)
  61                 return -EINVAL;
  62         if (!target_vcpu->arch.power_off)
  63                 return SBI_HSM_STATE_STARTED;
  64         else if (vcpu->stat.generic.blocking)
  65                 return SBI_HSM_STATE_SUSPENDED;
  66         else
  67                 return SBI_HSM_STATE_STOPPED;
  68 }
  69
  70 static int kvm_sbi_ext_hsm_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
  71                                    unsigned long *out_val,
  72                                    struct kvm_cpu_trap *utrap,
  73                                    bool *exit)
  74 {
  75         int ret = 0;
  76         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
  77         struct kvm *kvm = vcpu->kvm;
  78         unsigned long funcid = cp->a6;
  79
  80         switch (funcid) {
  81         case SBI_EXT_HSM_HART_START:
  82                 mutex_lock(&kvm->lock);
  83                 ret = kvm_sbi_hsm_vcpu_start(vcpu);
  84                 mutex_unlock(&kvm->lock);
  85                 break;
  86         case SBI_EXT_HSM_HART_STOP:
  87                 ret = kvm_sbi_hsm_vcpu_stop(vcpu);
  88                 break;
  89         case SBI_EXT_HSM_HART_STATUS:
  90                 ret = kvm_sbi_hsm_vcpu_get_status(vcpu);
  91                 if (ret >= 0) {
  92                         *out_val = ret;
  93                         ret = 0;
  94                 }
  95                 break;
  96         case SBI_EXT_HSM_HART_SUSPEND:
  97                 switch (cp->a0) {
  98                 case SBI_HSM_SUSPEND_RET_DEFAULT:
  99                         kvm_riscv_vcpu_wfi(vcpu);
 100                         break;
 101                 case SBI_HSM_SUSPEND_NON_RET_DEFAULT:
 102                         ret = -EOPNOTSUPP;
 103                         break;
 104                 default:
 105                         ret = -EINVAL;
 106                 }
 107                 break;
 108         default:
 109                 ret = -EOPNOTSUPP;
 110         }
 111
 112         return ret;
 113 }
 114
 115 const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_hsm = {
 116         .extid_start = SBI_EXT_HSM,
 117         .extid_end = SBI_EXT_HSM,
 118         .handler = kvm_sbi_ext_hsm_handler,
 119 };