arch/riscv/kvm/vcpu_sbi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2019 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_linux_err_map_sbi(int err)
  16 {
  17         switch (err) {
  18         case 0:
  19                 return SBI_SUCCESS;
  20         case -EPERM:
  21                 return SBI_ERR_DENIED;
  22         case -EINVAL:
  23                 return SBI_ERR_INVALID_PARAM;
  24         case -EFAULT:
  25                 return SBI_ERR_INVALID_ADDRESS;
  26         case -EOPNOTSUPP:
  27                 return SBI_ERR_NOT_SUPPORTED;
  28         case -EALREADY:
  29                 return SBI_ERR_ALREADY_AVAILABLE;
  30         default:
  31                 return SBI_ERR_FAILURE;
  32         };
  33 }
  34
  35 #ifndef CONFIG_RISCV_SBI_V01
  36 static const struct kvm_vcpu_sbi_extension vcpu_sbi_ext_v01 = {
  37         .extid_start = -1UL,
  38         .extid_end = -1UL,
  39         .handler = NULL,
  40 };
  41 #endif
  42
  43 static const struct kvm_vcpu_sbi_extension *sbi_ext[] = {
  44         &vcpu_sbi_ext_v01,
  45         &vcpu_sbi_ext_base,
  46         &vcpu_sbi_ext_time,
  47         &vcpu_sbi_ext_ipi,
  48         &vcpu_sbi_ext_rfence,
  49         &vcpu_sbi_ext_srst,
  50         &vcpu_sbi_ext_hsm,
  51         &vcpu_sbi_ext_experimental,
  52         &vcpu_sbi_ext_vendor,
  53 };
  54
  55 void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
  56 {
  57         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
  58
  59         vcpu->arch.sbi_context.return_handled = 0;
  60         vcpu->stat.ecall_exit_stat++;
  61         run->exit_reason = KVM_EXIT_RISCV_SBI;
  62         run->riscv_sbi.extension_id = cp->a7;
  63         run->riscv_sbi.function_id = cp->a6;
  64         run->riscv_sbi.args[0] = cp->a0;
  65         run->riscv_sbi.args[1] = cp->a1;
  66         run->riscv_sbi.args[2] = cp->a2;
  67         run->riscv_sbi.args[3] = cp->a3;
  68         run->riscv_sbi.args[4] = cp->a4;
  69         run->riscv_sbi.args[5] = cp->a5;
  70         run->riscv_sbi.ret[0] = cp->a0;
  71         run->riscv_sbi.ret[1] = cp->a1;
  72 }
  73
  74 void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
  75                                      struct kvm_run *run,
  76                                      u32 type, u64 reason)
  77 {
  78         unsigned long i;
  79         struct kvm_vcpu *tmp;
  80
  81         kvm_for_each_vcpu(i, tmp, vcpu->kvm)
  82                 tmp->arch.power_off = true;
  83         kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
  84
  85         memset(&run->system_event, 0, sizeof(run->system_event));
  86         run->system_event.type = type;
  87         run->system_event.ndata = 1;
  88         run->system_event.data[0] = reason;
  89         run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
  90 }
  91
  92 int kvm_riscv_vcpu_sbi_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
  93 {
  94         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
  95
  96         /* Handle SBI return only once */
  97         if (vcpu->arch.sbi_context.return_handled)
  98                 return 0;
  99         vcpu->arch.sbi_context.return_handled = 1;
 100
 101         /* Update return values */
 102         cp->a0 = run->riscv_sbi.ret[0];
 103         cp->a1 = run->riscv_sbi.ret[1];
 104
 105         /* Move to next instruction */
 106         vcpu->arch.guest_context.sepc += 4;
 107
 108         return 0;
 109 }
 110
 111 const struct kvm_vcpu_sbi_extension *kvm_vcpu_sbi_find_ext(unsigned long extid)
 112 {
 113         int i = 0;
 114
 115         for (i = 0; i < ARRAY_SIZE(sbi_ext); i++) {
 116                 if (sbi_ext[i]->extid_start <= extid &&
 117                     sbi_ext[i]->extid_end >= extid)
 118                         return sbi_ext[i];
 119         }
 120
 121         return NULL;
 122 }
 123
 124 int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu, struct kvm_run *run)
 125 {
 126         int ret = 1;
 127         bool next_sepc = true;
 128         bool userspace_exit = false;
 129         struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
 130         const struct kvm_vcpu_sbi_extension *sbi_ext;
 131         struct kvm_cpu_trap utrap = { 0 };
 132         unsigned long out_val = 0;
 133         bool ext_is_v01 = false;
 134
 135         sbi_ext = kvm_vcpu_sbi_find_ext(cp->a7);
 136         if (sbi_ext && sbi_ext->handler) {
 137 #ifdef CONFIG_RISCV_SBI_V01
 138                 if (cp->a7 >= SBI_EXT_0_1_SET_TIMER &&
 139                     cp->a7 <= SBI_EXT_0_1_SHUTDOWN)
 140                         ext_is_v01 = true;
 141 #endif
 142                 ret = sbi_ext->handler(vcpu, run, &out_val, &utrap, &userspace_exit);
 143         } else {
 144                 /* Return error for unsupported SBI calls */
 145                 cp->a0 = SBI_ERR_NOT_SUPPORTED;
 146                 goto ecall_done;
 147         }
 148
 149         /* Handle special error cases i.e trap, exit or userspace forward */
 150         if (utrap.scause) {
 151                 /* No need to increment sepc or exit ioctl loop */
 152                 ret = 1;
 153                 utrap.sepc = cp->sepc;
 154                 kvm_riscv_vcpu_trap_redirect(vcpu, &utrap);
 155                 next_sepc = false;
 156                 goto ecall_done;
 157         }
 158
 159         /* Exit ioctl loop or Propagate the error code the guest */
 160         if (userspace_exit) {
 161                 next_sepc = false;
 162                 ret = 0;
 163         } else {
 164                 /**
 165                  * SBI extension handler always returns an Linux error code. Convert
 166                  * it to the SBI specific error code that can be propagated the SBI
 167                  * caller.
 168                  */
 169                 ret = kvm_linux_err_map_sbi(ret);
 170                 cp->a0 = ret;
 171                 ret = 1;
 172         }
 173 ecall_done:
 174         if (next_sepc)
 175                 cp->sepc += 4;
 176         if (!ext_is_v01)
 177                 cp->a1 = out_val;
 178
 179         return ret;
 180 }